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[Display omitted] • A high-stable and long lifespan cathodes, guest ions Mn2+ or Zn2+ pre-inserting in NaV 6 O 15 , was prepared. • Guest ions pre-insertion improves charge transfer kinetics and surface reaction kinetics, enhancing electrochemical performance. • Due to the larger ionic radius of Zn2+, ZNVO cathode is more stable and has a wider tunnel space than that of MNVO. • At a current density of 5 A g-1, ZNVO exhibited a capacity of 113.7 mAh g-1 after 5000 cycles without capacity fading. Vanadium-based compounds, characterized by diverse crystal structures, exhibit high theoretical capacities, and are regarded as potential cathode materials for aqueous zinc-ion batteries. Despite this, their development has been hindered by the sluggish diffusion of zinc ions and inadequate structural stability. In this study, we fabricated a stable monoclinic NaV 6 O 15 nanorod via a simple hydrothermal synthesis. Mn2+ or Zn2+ ions are introduced into the crystal lattice to augment the interlayer spacing of NaV 6 O 15 , thereby enhancing the diffusion kinetics of Zn2+ ions. After pre-intercalating guest ions (Mn2+/Zn2+), the material experiences a morphological evolution from nanorods to nanobelts, which correlates with an expansion of the specific surface area and a proliferation of electrochemically active sites. This morphological alteration is associated with a marked enhancement in reversible capacity, reaching 278.1, 340.4, and 363.9 mAh/g for NVO, MNVO, and ZNVO, respectively, at 0.2 A/g. Furthermore, pre-intercalating guest ions not only expanded the interlayer spacing but also conferred structural robustness, leading to a pronounced enhancement in Zn2+ mobility and cyclability. Remarkably, the ZNVO cathode demonstrated a capacity retention of 118.4 % after 5000 cycles at a high current density of 5 A/g. Additionally, ex-situ XRD and XPS analyses elucidate that the Zn2+ storage in ZNVO is governed by the Zn2+ insertion/de-insertion mechanism. Our research offers a paradigm for the development of cathode materials for aqueous zinc-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • TiO2/MoSe2 nanocomposite shows enhanced electrochemical capacitance over pure TiO 2. • Hydrothermal synthesis forms high ECSA TiO 2 nanotubes with MoSe 2 for energy storage. • TiO2/MoSe2 exhibits tenfold higher capacitance than pristine TiO 2 nanotubes. This study presents the hydrothermal synthesis of a novel TiO 2 nanotubes/MoSe 2 nanocomposite and investigates its enhanced electrochemical capacitance properties. The composite material was fabricated through a hydrothermal method, embedding MoSe 2 onto TiO 2 nanotubes. The resulting composite, termed Ti/TiO 2 /MoSe 2 , exhibited significantly improved electrochemical capacitance compared to TiO 2 nanotubes alone. The synthesized composite was comprehensively characterized using solid-state physics techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). These analyses provided detailed insights into the structural and chemical composition of the TiO 2 /MoSe 2 nanocomposite. The investigation revealed that the TiO 2 /MoSe 2 nanocomposite displayed superior electrochemical performance, as determined by various electrochemical methods. Notably, the composite exhibited a capacitance approximately 10 times higher than that of pristine TiO 2 nanotubes. These findings underscore the significant enhancement in energy storage capabilities achieved through the hydrothermal synthesis of TiO 2 /MoSe 2. The observed enhancement in capacitance positions the TiO 2 /MoSe 2 nanocomposite as a promising candidate for high-performance energy storage applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pure and mixed BFO phases were prepared by a single-pot hydrothermal synthesis process. • The mineralizer type plays a critical role in the BiFeO 3 crystal phase purity. • Constructing dual Z-Scheme heterojunction through one-pot synthesis. • Dual heterostructure m-BFO showed outstanding stability and reusability efficiency. This study proposes a novel approach for preparing bismuth ferrite (BiFeO 3 , BFO) with controlled crystal phase purity and morphology via a one-pot hydrothermal process using specific mineralizers (NaOH or KOH). The effects of these mineralizers on the crystal purity and photocatalytic efficiency of the catalyst were investigated. The XRD results revealed that KOH produced pure BFO, whereas NaOH yielded mixed-phase BFO (m-BFO) with secondary phases, including Bi 2 O 3 and Bi 2 Fe 4 O 9. SEM analysis revealed that m-BFO exhibited a flake-like structure assembled into cubes, whereas pure BFO consisted of irregularly shaped agglomerated nanoparticles. The photocatalytic efficiency of the two catalysts was evaluated for the degradation of 4-nitrophenol (4-NP). The results showed that m-BFO exhibited outstanding photocatalytic degradation performance (92%) for 4-NP compared with pure BFO (22%). The enhanced photocatalytic efficiency of m-BFO was attributed to the construction of a dual-heterojunction Z-scheme within its structure and the presence of abundant surface oxygen vacancies. This study provides valuable insights into the synthesis of efficient dual-heterojunction Z-scheme photocatalysts via one-pot hydrothermal synthesis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal synthesis of 2D nanosheets assembled MoSe 2 flowers. • Controlled oxidation of MoSe 2 to convert into MoSe 2-x O y. • Au/MoSe 2-x O y /Au exhibited filamentary type bipolar resistive switching. • Coexistence of MoSe 2 and MoO x (x < 3) enhanced memristive performance. • Valance change mechanism was dominant due to presence of MoOx in MoSe 2. The current study shows an improvised resistive switching in oxygenated MoSe 2 (MoSe 2-x O y) thin film. 2D nanosheets assembled nanoflower morphology of MoSe 2 was synthesized with hydrothermal route and then treated with thermal oxidation process at 300⁰C in presence of 0, 0.5, 5 and 20 % of oxygen. The coexistence of MoSe 2 and MoO x in each samples was investigated with various spectroscopic techniques. The conversion to MoO x was maximum in 20 % O 2 treated sample while other samples were converted partially. Au/MoSe 2-x O y /Au structured devices were fabricated on SiO 2 /p-Si substrate and tested for resistive switching study. Among all four devices, 5 % O 2 treated MoSe 2-x O y exhibited excellent filamentary type bipolar resistive switching with very low SET and RESET voltages of + 0.84 V and −0.79 V, respectively. The device showed I ON /I OFF ratio ∼50 (at read voltage: 0.5 V) with excellent retention (106 s) and endurance (100 cycles) characteristics with minimum cycle-to-cycle variation. The resistive switching mechanism was explained with valance change conducting filament formation/rupture model and the trap-controlled space charge limited current behavior. Rich transport properties of 2D-chalcogenide (MoSe 2) and classic oxygen vacancy migrated switching of metal oxide (i.e. MoO x), were simultaneously important for achieving high performance memristive behavior in 5 % O 2 treated MoSe 2. [ABSTRACT FROM AUTHOR]

A novel Ag/Bi 2 MoO 6 /ZnO heterojunction was prepared using a two-step microwave-assisted hydrothermal method to photocatalytic degradation of LFX in water. [Display omitted] • Ag/BMO/ZnO heterojunction with Ag as the electronic accelerator pump was constructed. • Ag/BMO/ZnO shows superior photocatalytic degradation efficiency ∼86.4 % toward LFX. • The accelerated transfer and retarded recombination for charges are the main reason. • The 1O 2 the predominant role in the degradation process of LFX. • The possible degradation pathway was proposed by identifying the intermediates. The fluoroquinolone antibiotics, as a category of emerging refractory organic pollutants, have triggered intensive attention due to their persistent ecotoxicology for aquatic environments. Herein, a novel Ag/Bi 2 MoO 6 /ZnO (Ag/BMO/ZnO) heterojunction was prepared using a two-step microwave-assisted hydrothermal method for photocatalytic degradation of levofloxacin (LFX). The optimal Ag/BMO/ZnO delivers higher photocatalytic degradation efficiency toward LFX reaching 86.4 %, which is 3 times and 7 times higher than those of neat Bi 2 MoO 6 and ZnO, respectively. This can mainly be attributed that the existence of heterojunction between Bi 2 MoO 6 and ZnO promotes the transmission of photogenerated charges (e−/h+). Furthermore, the introduction of Ag nanoparticles serves as an electron accelerator pump, which can also effectively accelerate the transport and separation of the photogenerated e−/h+. Both of these indirectly retard the recombination of e−/h+. The radical capture assays demonstrate that 1O 2 , OH, h+ and O 2 – are responsible for the the degradation of LFX and the 1O 2 is the primary reactive oxygen species (ROS). Moreover, based on the identification of degradation intermediates via the liquid-chromatography-mass spectrometry (LC-MS) technique, the possible degradation routes of LFX were plausibly inferred. In conclusion, this work provides a new perspective toward antibiotics removal by developing novel heterojunction photocatalysts anchored with precious nanoparticles. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hydrothermal synthesis combined with atomic layer deposition strategy for synthesizing NiO x @Co 3 O 4 nanoneedles on carbon cloth. • By introducing Ni species, the OER performance of the material in alkaline seawater is enhanced, and atomic-level controllable optimization of the Ni-O-Co interface is achieved. • The obtained NiO x @Co 3 O 4 heterojunction catalyst exhibiting extremely low overpotential (235 mV @ 10 mA cm−2) and outstanding stability (300 h) in alkaline seawater environments. In seawater electrolysis for hydrogen production, the competition between chlorine evolution and oxygen evolution reaction (OER) at the anode limits its hydrogen yield and system stability. To address this, we optimized the anode material by modulating the surface electronic structure of the active sites of Co 3 O 4 using atomic layer deposition (ALD) technology. By introducing the atomic layers of NiO x species, this approach results in the synthesis of a NiO x @Co 3 O 4 /Carbon cloth (CC) heterojunction, which serves as an effective oxygen evolution reaction electrocatalyst for high-performance seawater electrolysis. Adjusting the deposition cycles creates unique material interfaces that facilitate the transformation of reaction intermediate. The NiO x @Co 3 O 4 /CC heterostructure demonstrates superior catalytic performance over single-phase materials, which is attributed to its unique Ni-O-Co interface, showing low overpotentials of 204 mV in alkaline freshwater and 235 mV in seawater solutions at 10 mA cm−2, 285 mV in alkaline freshwater and 329 mV in seawater solutions at 100 mA cm−2. In addition, the incorporation of NiO x endowed the material with enhanced overall durability and corrosion resistance, reducing Cl-related species adsorption. After 300 h of chronoamperometric testing, the voltage remained stable, indicating its potential as an ideal electrocatalyst for seawater electrolysis under alkaline conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface facet engineering of ZnIn 2 S 4 was achieved via supercritical hydrothermal synthesis. • Transformation from flower-like to hexagonal plate morphology enhances NO gas sensing. • Hexagonal ZnIn 2 S 4 exhibits a significant increase in the (003)/(011) facet ratio. • Enhanced NO sensing performance due to optimized surface interaction with ZnIn 2 S 4 facets. In this study, we investigate the novel application of ZnIn 2 S 4 as an NO gas detection device by precisely modulating its surface facets through crystal growth control in a supercritical water environment. The supercritical hydrothermal synthesis successfully transforms ZnIn 2 S 4 from a flower-like structure into a hexagonal plate morphology, driven by the preferential growth of the basal plane (003) surface facet. This morphological control, which is unattainable in a subcritical environment, is evidenced by a substantial increase in the (003)/(011) facet ratio from 0.52 to 1.98 with rising temperature. NO detection results indicate that this surface morphology modification significantly accelerates sensor response, attributed to enhanced interaction between the ZnIn 2 S 4 surface and NO gas, as well as reduced diffusion limitations compared to the flower-like morphology. The hexagonal plates exhibit a remarkably fast response time of approximately 25 s, in contrast to 181 s for the flower-like counterpart. These findings underscore the crucial role of surface facet engineering in optimizing the gas-sensing properties of ZnIn 2 S 4 , highlighting its potential for advanced gas sensor applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The multilayer Ti 3 C 2 T x @MoS 2 composite coating was prepared by hydrothermal and drop coating methods. • The stable tribofilm was formed during the friction process after surface treatment. • The composite coating exhibited a low friction coefficient and a high service life. • The enhanced performance was attributed to the frame support of Ti 3 C 2 T x and the lubrication of MoS 2. To reduce wear and energy loss during the movement of miniaturized devices such as wearable devices and MEMS, and to address the inherent limitations of individual categories of solid lubricating materials, a new MXene-based composite solid lubricating material was designed. In this study, Ti 3 C 2 T x @MoS 2 composites were successfully prepared via hydrothermal synthesis, with MoS 2 nanosheets grown uniformly on the surface and interval of the multilayer Ti 3 C 2 T x. The composites were deposited as a solid lubricant coating on silicon substrates using a drop coating method. Tribological behavior was evaluated by ball-on-disk reciprocating and rotating tribometer, respectively. The results revealed that the friction coefficients of the multilayer Ti 3 C 2 T x @MoS 2 composite coatings were reduced by 75%, 69%, and 58%, respectively, compared to the multilayer Ti 3 C 2 T x , MoS 2 , and their mechanical mixtures. Moreover, this study proposed the excellent wear resistance of the multilayer Ti 3 C 2 T x @MoS 2 composite coatings was attributed to the synergistic lubrication of Ti 3 C 2 T x and MoS 2. MoS 2 was enriched in the wear track, and the tribofilm formed during friction process played the role of friction reduction and lubrication. In comparison, the multilayer Ti 3 C 2 T x had an excellent effect on the wear resistance and structural support. [ABSTRACT FROM AUTHOR]

[Display omitted] • PNGN was synthesized by hydrothermal approach. • PANI/PNGN 15% composite synthesized by in-situ polymerization method. • The sensor has shown sensing response ∼810 %, detection limit of 0.012 ppm. • Response time and recovery time are 21 s and 56 s. • PANI/PNGN 15% exhibits a remarkable specific capacitance of 750.41 F g−1 at 5 Ag−1. In the pursuit of developing advanced materials with multifunctional capabilities, the integration of polymers and graphene-based materials has garnered significant attention. In the quest for the synergy between polyaniline (PANI) and phosphorus, nitrogen dual co-doped graphene (PNGN) has emerged as a promising avenue for multifunctional applications in supercapacitors and gas sensing devices. The PANI/PNGN 15 % nanocomposites were synthesized by a combination of hydrothermal processing and in-situ polymerization techniques. The synthesized nanocomposites were characterized using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies. The PANI/PNGN 15 % nanocomposite sensor has shown sensing response values of ∼810 %, the response time of 21 s, recovery time of 56 s, and a detection limit of 0.082 ppm. The PANI/PNGN 15 % nanocomposite achieved a remarkable specific capacitance of 750.41 F g−1 at a current density of 5 A g−1. Moreover, the symmetrical supercapacitor exhibits remarkable rate capability, achieving (∼82.14 % at 5 Ag−1), while also maintaining excellent cycling stability. The synergistic effects of PANI and PNGN contribute to the development of high-performance devices, paving the way for advancements in the fields of supercapacitors and gas sensing technologies. [ABSTRACT FROM AUTHOR]

Sb-derived heterostructures, including Sb 2 O 3 /SnO 2 heterostructure and Sb 2 S 3 /SnS 2 heterostructure, were prepared by a one-step hydrothermal method using exfoliated Sb nanoflakes as Sb source. The as-synthesized Sb 2 S 3 /SnS 2 heterostructure photocatalyst exhibited excellent photocatalytic activity. [Display omitted] • Sb nanoflakes were used to prepare Sb 2 O 3 /SnO 2 and Sb 2 S 3 /SnS 2 heterostructures. • The slow release of Sb3+ ions from Sb nanoflakes led to uniform heterostructures. • Sb 2 S 3 and SnS 2 formed the type-II heterojunction. • The Sb 2 S 3 /SnS 2 heterostructures exhibited superior photocatalytic activity. Antimony (Sb) based compounds such as Sb 2 O 3 and Sb 2 S 3 have shown promises in electronics, catalysis and sensing devices. Their functional performances can be further improved by integration with other materials to from composites or heterostructures, which however, usually require tedious procedures with poor morphology control. Herein, we realized direct hydrothermal synthesis of Sb 2 O 3 /SnO 2 heterostructures and Sb 2 S 3 /SnS 2 heterostructures by using liquid-phase exfoliated two-dimensional (2D) Sb nanoflakes as precursors. Compared to directly using SbCl 3 salt as the reactant, using the Sb nanoflakes enabled the slow release of Sb3+ ions which benefited the better controlled nucleation and growth of Sb 2 O 3 (or Sb 2 S 3) acting as growth templates for the further deposition of SnO 2 (or SnS 2). As a demonstration, the as-prepared Sb 2 S 3 /SnS 2 heterostructures were employed for photocatalytic methylene blue (MB) degradation, which exhibited a faster degradation rate compared to Sb 2 S 3 or SnS 2 alone. Our work offers an alternative strategy with elemental 2D materials as precursors for the preparation of heterostructured functional materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The MnF 2 @NC composite, consisting of micro-nanostructured pores and comprising MnF 2 nanoparticles encapsulated within a nitrogen-doped carbon shell, is achieved through a cost-effective and one-step fluorination strategy. • As anode for LIBs, the MnF 2 @NC electrode exhibits exceptional cycling performance and rate capability. MnF 2 , an intriguing anode material for lithium-ion batteries (LIBs), has garnered significant attention due to its high theoretical capacity. However, its commercial viability is impeded by issues such as volume expansion and poor conductivity. In this study, we present the development and fabrication of MnF 2 @NC microspheres with micro-nanostructured pores, comprising MnF 2 nanoparticles encapsulated within a nitrogen-doped carbon shell. This was achieved through a combination of hydrothermal synthesis and fluorination techniques. The MnF 2 @NC composite exhibits a high level of porosity, effectively mitigating the significant volume expansion of MnF 2 and facilitating efficient charge transport. Moreover, the incorporation of nitrogen-doped carbon shell enhances the overall structural and promotes electrical conductivity. Leveraging these inherent characteristics, the MnF 2 @NC electrode demonstrates exceptional electrical conductivity and superior long-term stability. The MnF 2 @NC electrode serves as an anode for LIBs, exhibiting a remarkable reversible capacity of 991.2 mAh/g at 0.1 A/g, exceptional cycle performance with a capacity retention of 872.2 mAh/g after 700 cycles at 1.0 A/g, and outstanding rate capability surpassing the reported outcomes of MnF 2 -based composite anodes. These results unequivocally demonstrate the suitability and potential applicability of MnF 2 @NC as high-capacity anodes for LIB. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiO nanoparticles hydrothermally synthesized and calcined at 400 °C and 500 °C. • Metallic nickel clusters close to surface evidenced by EPR. • Ni clusters decrease in 400 °C calcined NiO after 2 h air annealing at 500 °C. • Ni clusters increase in 400 °C calcined NiO after 2 h vacuum annealing at 500 °C. • CO sensing properties dependant on the thermal history of the NiO samples. The outstanding properties exhibited by the p-type NiO nanostructures can be greatly affected by morpho-structural and defect characteristics with constructive or competing effects. We have conducted an in-depth study on NiO nanoparticles obtained by hydrothermal synthesis and submitted to various thermal treatments, to monitor the evolution of their structural properties and the effect of the thermal history on their CO sensing. Correlated electron paramagnetic resonance and analytical transmission electron microscopy investigations evidenced an amount of up to 1 % metallic nickel clusters close to surface in the NiO nanoparticles calcined at 400 °C and 500 °C for 8 h. Subsequent annealing in vacuum and in air of the sample calcined at 400 °C resulted in different size distributions and morphology of the NiO nanoparticles and an increase/decrease of the nickel phase, respectively. Comparative CO sensing tests on the two pristine samples and on the sample calcined at 400 °C and further annealed in air at 500 °C for 2 h showed an increase in the baseline resistance of the later due to the decrease of free charge carriers induced by the dissolution of the nickel clusters. The overall CO sensing results show a strong dependence on the samples thermal history. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface modification of cellulose has improved synthesis of piezoelectric ZnO. • The cellulose@ZnO composite has excellent dielectric and piezoelectric property. • Output voltage and current is elevated to be 25.6 V and 1100 nA, respectively. • The flexible piezoelectric composite has conspicuous strain sensing performance. While the existed researches about cellulose based piezoelectric composite focused on the direct growth of ZnO on surface of cellulose based paper or membrane, this paper reports a ZnO based piezoelectric composite fabricated by growing ZnO in the cellulose nanofibril (CNF) dispersion substrate via two-step hydrothermal synthesis. After CNF was controllably oxidized to endow with appropriate carboxyl groups and size, it was used as a template and dispersant for in-situ polymerization of ZnO to be CNF@ZnO. Zn2+ is preferentially fixed on the scattered CNF for its active hydroxyl and carboxyl groups which serve as a uniform nucleation for the self-assembly of ZnO, so that it has a preferential orientation with optimal phase structure, one-dimensional rod-like structure, excellent dispersity, low interface energy and interfacial compatibility. Thus the assembled 4CNF/4CNF@ZnO composite membrane has a large elevation in the dielectric properties and piezoelectric performance. Moreover, the 4CNF/CNF@ZnO piezoelectric composite vacuum-impregnated with PDMS exhibits better piezoelectric performance with the open-circuit voltage as high as 25.6 V and the short-circuit current of 1100 nA. It can supply to light LED and has high sensitivity to body movement, indicating its great potential in pressure sensors and generators. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal synthesis of multifunctional continuous solid solution photocatalyst. • Solid solutions enjoy magnetic, adsorption, and dual absorption, etc. • Solid solutions enjoy high efficiency of pollutant removal and CO 2 methanation. • Semiconductor bandgap was freely adjusted by the element ratios. Multifunctional continuous solid solutions Na 0.9 Mg 0.45 Ti 3.55 O 8 -Na 2 Fe 2 Ti 6 O 16 (NFMTO- x) were synthesized via a one-step hydrothermal method by controlling the ratio of Mg and Fe. The NFMTO- x continuous solid solutions share same monoclinic structure of space group C 2/ m and same morphology of long hexagonal nanosheets with Na 0.9 Mg 0.45 Ti 3.55 O 8 (NMTO) and Na 2 Fe 2 Ti 6 O 16 (NFTO). XPS and EDX results reveal five elements Na, Mg, Fe, Ti, and O in the continuous solid solutions to confirm the change in Mg and Fe contents. The NFMTO- x continuous solid solutions enjoy dual absorption, significantly expanding their visible light response in comparison with pure NMTO. The organic pollutant methylene blue (MB) was effectively degraded through the NFMTO- x adsorption and photocatalysis, which exhibits higher performances than the pure NMTO and NFTO. Effective adsorption towards dyes is an important prerequisite to promote photocatalytic effectivity. LC-MS and TOC tests at different times reveal that MB dye was effectively mineralized to some degradation intermediates. NFMTO- x samples also have a certain capacity for CO 2 methanation, converting CO 2 to CO and CH 4. The magnetic properties let us easily collect the powders from water after photodegradation for recycling utilization. The electron spin resonance identified O2− as the important active group in photocatalytic degradation. This research provides a significant multifunctional material used in water purification. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) have become a potential alternative to photovoltaic devices, which can convert solar energy into electrical energy. As an essential component of DSSCs, counter electrode (CE) materials play an important role in determining the performance of DSSCs. Thus, research should seek for a cost-effective and high-activity CE materials. In this work, we explored an efficient, low-cost (platinum (Pt)-free) CE made of hybrids of In 2.77 S 4 nanoparticles and reduced graphene oxide (RGO) for DSSCs. In 2.77 S 4 -RGO hybrids were facilely synthesized via a one-step hydrothermal approach without template or complicated precursor. Especially during synthesis, glacial acetic acid was added to prevent the precipitation of In3+ ions. Thus, free In3+ and S2− ions can readily absorb onto the graphene oxide (GO) surface by electrostatic forces. Finally, In 2.77 S 4 nanoparticle-doped GO hybrids were obtained under hydrothermal conditions. Based on electrochemical measurement in cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization curve tests, the as-prepared mesoporous In 2.77 S 4 -RGO hybrids exhibited remarkable electrocatalytic properties, charge–transfer capabilities, and electrochemical stabilities. As a result, the DSSCs assembled with In 2.77 S 4 -RGO hybrid CE exhibited a powder conversion efficiency of 6.72%, which is superior to that with Pt CE (6.30%). These findings suggest that In 2.77 S 4 -RGO hybrids can be used as a promising alternative CE in DSSCs. Unlabelled Image • In 2.77 S 4 -RGO hybrids were synthesized via a one-step hydrothermal approach. • The electrocatalytic activity of In 2.77 S 4 -RGO was attributed to synergistic effects. • The PCE of In 2.77 S 4 -RGO hybrids CE (6.72%) is superior to that of Pt CE (6.30%). • In 2.77 S 4 -RGO hybrids can be used as a promising alternative CE in DSSCs. [ABSTRACT FROM AUTHOR]

In present work, SnO 2 nanoparticles were synthesized using simple hydrothermal process, and then a novel PbO 2 /SnO 2 electrode was successfully fabricated using obtained SnO 2 nanoparticles for electrochemical oxidation of 3-chlorophenol (3-CP). The microstructure, element distribution, crystal structure and chemical composition of samples were characterized by the analytical techniques including SEM, EDS, XRD and XPS. The electrochemical performances of electrodes were evaluated using LSV and CV measurements. The ·OH radicals generation capacity of electrodes was determined using terephthalic acid as trapping agent. Moreover, the PbO 2 /SnO 2 electrodes were applied in the electrochemical degradation of 3-CP in aqueous solution. The results show that the doping of SnO 2 nanoparticles reduced the grain size of PbO 2 crystal and improved the content of O ads on the surface of electrode. In contrast with the pure PbO 2 electrode, the PbO 2 /SnO 2 -1.0 electrode (the concentration of SnO 2 in electroplating solution was 1.0 g/L) exhibited higher oxygen evolution potential, stronger direct oxidation capacity and ·OH radicals generation capacity, and superior electrochemical activity for degradation of 3-CP. The intermediates formed in electrochemical degradation of 3-CP were revealed by HPLC and a plausible degradation pathway was proposed. Furthermore, PbO 2 /SnO 2 -1.0 electrode also showed a high reusability for 3-CP degradation. Unlabelled Image • PbO 2 /SnO 2 composite anode was successfully fabricated for electrochemical oxidation. • Electrocatalytic properties of PbO 2 /SnO 2 anode were evaluated. • The degradation intermediates of 3-CP were identified and pathway was elucidated. [ABSTRACT FROM AUTHOR]

The development of sustainable energy conversion and storage systems is on demand to ease the energy needs and restrict environmental pollution. Here, we account a unique multifunctional flake-like CoS deposited over the flexible carbon cloth (CoS@CC) by a facile hydrothermal technique. The single-phase hexagonal structured CoS@CC with high crystallinity was identified through the XRD analysis. The morphological feature portrays the uniform distribution of flake-like CoS over carbon cloth. The electrocatalytic properties of the prepared flake-like CoS (CoS@CC) suggests improved electroactivity of requiring minimal overpotentials of 280 mV (OER) and 264 mV (HER) to accomplish a pre-eminent current density of 20 mA cm−2. In addition, a lab-scale water splitting system was projected to achieve a current density of 10 mA cm−2 with a low cell voltage of 1.65 V. In view to driving the fabricated water splitting system, a flexible (CoS@CC||rGO) supercapattery was fabricated to deliver an improved specific energy of 38 Wh kg−1 at a superior specific power of 533 W kg−1. Therefore, the prepared CoS@CC electrode with improved flexibility, useful catalytic activity, expressive kinetics, and resilient strength serves as a multifunctional material for prospective energy conversion and storage systems. Unlabelled Image • Development of solitary cost-effective CoS@CC as binder-free multifunctional electrode • Understanding the surface activity of CoS@CC electrode in the electrocatalytic and electrochemical analysis • The binder-free CoS@CC electrode shows superior catalytic activity with excellent durability. • The fabricated CoS@CC||rGO demonstrated improved energy density with better cyclic stability. • Sustainable multifunctional electrodes for efficient energy storage and water splitting systems [ABSTRACT FROM AUTHOR]

TiO 2 nanoparticles (NPs) are capable of inhibiting the growth of bacterial strains and are responsible for causing damages to the cancer cells. Pure TiO 2 , Aqua Rosa-modified TiO 2 and protein powder-modified TiO 2 NPs are synthesized using hydrothermal method. The particle size is found to be 7.5 nm for pure, 6.5 nm for protein-modified and 5.5 nm for Aqua Rosa-modified TiO 2 NPs using TEM analysis. UV spectra shows that the absorption peaks of the modified samples are blue shifted with respect to pure TiO 2 nanoparticles. The surface-modified nanoparticles show maximum growth inhibition against the pathogenic organisms. The research experiments exhibited highest anti-cancer activities for the surface modified TiO 2 NPs. • Pure Titanium dioxide (TiO 2 NPs), Aqua Rosa and Protein powder modified TiO 2 NPs were synthesized by hydrothermal method using Titanium tetra isopropoxide as precursor. • Antibacterial and anticancer activities of Pure TiO 2 , Aqua Rosa and Protein Powder modified TiO 2 nanoparticles were investigated. • Antibacterial activities were performed against five bacterial strains namely Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus mutans . • Anticancer activities for the samples were performed in KB Oral cancer cell line. • The modified TiO 2 NPs indicate a greater efficiency on anticancer and antibacterial properties when compared with the Pure TiO 2 NPs. [ABSTRACT FROM AUTHOR]

For the first time, C-ZnO/BiVO 4 heterostructured nanocomposite has been synthesized from BiVO 4 and carbon-doped ZnO nanoparticles. X-ray diffraction (XRD) study showed themonoclinic scheelite structure of BiVO 4 and the hexagonal wurtzite structure of ZnO in the C-ZnO/BiVO 4 composite. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) images revealed the spherical nanoparticles of size 20 to 30 nm for C-ZnO. The band gap of the ZnO has turned towards the visible region by doping with carbon as well as a composite formation with visible light active material BiVO 4. The chemical states of Zn, O, C and Zn, O, C, Bi, V species in C-ZnO, and C-ZnO/BiVO 4 composite respectively were confirmed by X-ray photoelectron microscopy (XPS) analysis. Also, the XPS spectra showed the significant peaks shift in the electronic states of Zn, O, and C for the heterojunction composite. The suppression of the electron-hole recombination rate was confirmed from the quenching of photoluminescence (PL) intensity for the composite. The adsorption study has performed, and the experimental results fit well with the Langmuir isotherm model for understanding the catalytic activity of the samples. The possible Z -scheme photocatalytic mechanism of the C-ZnO/BiVO 4 nanocomposite photocatalyst has proposed. The nanocomposite exhibited the enhanced catalytic activity with the higher degradation rate constant of 0.050 min−1 for 50 min irradiation of visible light compared with their counterparts. • C-ZnO/BiVO 4 nanocomposite has higher pseudo first order kinetic rate constant. • The band gap of ZnO can be tuned into visible light via the formation of composite. • The influence of C and BiVO 4 in ZnO and their catalytic performances against MB dye. • The formation of hetero-junction suppressed the electron–hole recombination rate. [ABSTRACT FROM AUTHOR]

As a direct Z -scheme photocatalyst, a two-dimensional/two-dimensional (2D/2D) Bi 2 O 2 CO 3 /Bi 4 O 5 Br 2 (BOC/BOB) heterostructure was fabricated by stacking the ultrathin nanosheets of Bi 2 O 2 CO 3 and Bi 4 O 5 Br 2 via a simple one-step hydrothermal synthesis process. The atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM) results show that the heterostructure was successfully formed by coupling the ultrathin nanosheets of BOC and BOB. By optimizing the content of BOC, we found that the 30% BOC/BOB composite can exhibit a superior photocatalytic activity (53.2%) for NO x removal under simulated solar light illumination, which is much higher than that of single-phase BOC (20.4%) or BOB (37.9%). The results from trapping experiments and DMPO-ESR spin-trapping measurements demonstrate that both O 2 – and OH are the main active species during the photocatalytic reaction process. According to the DFT calculations, a Z -scheme heterojunction is formed between the BOC and BOB ultrathin nanosheets, in which the photo-induced electrons in BOC are combined with holes in BOB. This process can effectively hinder the recombination of photo-induced charge carriers in the BOC/BOB nanocomposites and resulting in the enhancement of charge separation efficiency. This work may shed light on developing more efficient photocatalysts by designing the 2D/2D Z -scheme heterostructures using ultrathin nanosheets. Unlabelled Image • Comparative experimental and DFT study of Bi 2 O 2 CO 3 /Bi 4 O 5 Br 2 , Z-scheme heterojunction is performed. • Bi 2 O 2 CO 3 /Bi 4 O 5 Br 2 shows significantly enhanced photoatalytic activity for NO removal. • Both OH and O 2 – radical species play the critical role in the photocatalytic process. [ABSTRACT FROM AUTHOR]

The novel heterojunction photocatalysts that TiO 2 modified rod-like g-C 3 N 4 with different ratios were fabricated via one-pot hydrothermal treatment, which using tetrabutyl titanate and traditional bulk-like g-C 3 N 4 powder as raw materials. The results show that the particles of TiO 2 are well-distributed on the surface of rod-like g-C 3 N 4. The photocatalytic performances were evaluated through photoredox water splitting and rhodamine B degradation test under visible light irradiation. By investigating the effects of different scavengers, it displays that the h+ and O2– played major role in the photocatalytic reactions. The synergic effect between TiO 2 and rod-like g-C 3 N 4 lead to an improved photogenerated carrier separation and enhance photocatalytic activities. The intermediates of the photodegradation process were identified by HPLC and LC/MS methods. The particles of TiO 2 are well-distributed on the surface of rod-like g-C 3 N 4. The rod-like g-C 3 N 4 can present more active sites and provide a long-distance to accelerate the separation of photo-generated electrons and holes. Unlabelled Image • TiO 2 modified one-dimensional rod-like g-C 3 N 4 was synthesized though a one-pot hydrothermal method. • Photoredox water splitting and rhodamine B degradation test under visible light irradiation were evaluated. • The synergistic effect between the coupled semiconductors assumes an enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]

Selective removal of 137Cs and 90Sr from aqueous environments is essential for the volume reduction and ultimate safe storage of nuclear waste. This study introduces a facile one-pot hydrothermal synthesis of Dual-cation form of TitanoSilicate (DTS, M 3 HTi 4 O 4 (SiO 4) 3 , M = Na+ and K+) for the effective and simultaneous removal of Cs+ and Sr2+. DTS showed enhanced adsorption capacities (469 mg/g for Cs+ and 179 mg/g for Sr2+) and the adsorption kinetics were extremely fast with around 98% and >99% removal achieved within 1 min from a dilute Cs+ and Sr2+ solution, respectively. Moreover, DTS indicated the superior selectivity for both Cs+ and Sr2+ due to the dual-cation incorporation in the structure. In groundwater, the distribution coefficients (K d at V/m = 1000 mL/g) for DTS were high for both Cs+ (1 ppm, 2.9 × 105 mL/g) and Sr2+ (1 ppm, 1.0 × 105 mL/g), and even in seawater DTS maintained a Cs+ (1 ppm) K d value as high as 4.9 × 104 mL/g. Remarkably, DTS is synthesized as a membrane with graphene oxide for continuous removal of the radionuclides, which is extremely beneficial to purifying a large volume of contaminated water. Unlabelled Image • Dual-cation form of DTS was synthesized via a facile one-pot hydrothermal route. • DTS showed superior Cs+ and Sr2+ adsorption capacities with very fast kinetics. • Even in real-water systems, DTS exhibited high selectivity for Cs+ and Sr2+. • DTS was used as a membrane with GO for continuous separation of Cs+ and Sr2+. [ABSTRACT FROM AUTHOR]

The photocatalytic activity of TiO 2 polymorphs has been frequently debated in literature. Numerous studies reported that rutile TiO 2 exhibits low photocatalytic activity, and it is generally accepted that rutile has lower photoactivity than the anatase phase. Herein, we studied the photocatalytic activity of phase-pure rutile TiO 2 nanoparticles prepared via microwave-assisted hydrothermal method (MW-R NPs). The syntheses were performed with relatively short reaction time (1−3 h) at 180 °C using a microwave digestion system. The samples were characterized in detail and then tested in the photodegradation of methyl orange (MO). We demonstrate that the photodegradation of MO with MW-R NPs is highly efficient in the presence of H 2 O 2. By employing 4.4 mM H 2 O 2 , ~90% of total decolorization was achieved after 2 min of UV-A irradiation. At the same experimental conditions, MO degradation with Degussa P25 TiO 2 was only ~7%. The superior photoactivity of MW-R NPs was related to the effective photogeneration of O 2 •− radicals as revealed by EPR investigation. These rutile nanoparticles are excellent photocatalysts in the presence of H 2 O 2 , signifying that this oxygen source react easily with the photogenerated holes on the MW-R NPs, and thus the interfacial charge transfer lead to the formation of a large amount of O 2 •− radicals. Unlabelled Image • Microwave-assisted hydrothermal synthesis of phase-pure rutile nanocrystallites • Extremely fast photocatalytic degradation of MO in the presence of H 2 O 2 • Effective capturing of photogenerated holes by H 2 O 2 on the rutile nanocrystallites • The crucial role of O 2 •− radicals in the photodegradation of MO is pointed out. [ABSTRACT FROM AUTHOR]

A highly three-dimensional CdIn 2 S 4 deposited TiO 2 (CdIS/TONR/FTO) heterostructured photoanode has been fabricated via a two-step hydrothermal process to enhance the photoelectrochemical (PEC) performance. In this work, bare TiO 2 nanorods are grown successfully on the fluorine-doped tin oxide (FTO) substrate via a hydrothermal method (TONR/FTO), and a second-step hydrothermal synthesis is used to grow CdIn 2 S 4 flower nanostructured layer over the top surface of the bare TONR/FTO. Structural, morphological, optical, and elemental analysis of CdIS/TONR/FTO heterostructure photoanode is investigated in detail. PEC performances are studied in 0.2 V versus Ag/AgCl in mixed sulfide-based electrolyte for various concentrations of CdIn 2 S 4 deposited on photoanodes. The photocurrent density for optimized (×4)-CdIS/TONR/FTO heterostructure photoanode is observed to be three times higher than that of the bare TONR/FTO photoanode. This excellent PEC performance is ascribed to the way that the deposited CdIn 2 S 4 layer and TiO 2 nanorods synergistically allow the absorption of a wide portion of the solar spectrum under back illumination, and provide efficient separation of the electron-hole pairs in the photoanode architecture. The EIS and IMPS analysis also reveal the significance of CdIn 2 S 4 layer that provides the lowest charge-transfer resistance at the interface and high electron-transfer rate in CdIS/TONR/FTO photoanode. Mainly, the deposited CdIn 2 S 4 layer significantly broadens the optical absorption capacity, and provides efficient electrons-holes transfer that reduces the recombination losses of the charge carriers. The proposed charge transfer mechanism in CdIS/TONR/FTO heterojunction is well studied. Unlabelled Image • Three-dimensional CdIS/TONR/FTO heterostructure photoanode is fabricated for PEC. • Three times higher photocurrent density observed for CdIS/TONR/FTO than bare sample. • Excellent PEC performance due to absorption of wide portion of the solar spectrum • Provides efficient separation of the electron-hole pairs in the photoanode. • Also, reduces the recombination losses of the charge carriers in photoanode. [ABSTRACT FROM AUTHOR]

Boron-doped mesoporous graphene (BMG) was synthesized via a hydrothermal process (BMG-h), utilizing the soft-template route tri-block co -polymer P123. To control the porous structure and boron configuration (BCO 2 and BC 2 O) of the graphitic domain, the obtained BMG-h was calcined at 1000 °C (BMG-c). The structural and compositional changes of the BMG were investigated by XRD, Raman, XPS, and N 2 adsorption-desorption isotherm measurements. The materials obtained have high BET specific surface area of up to 1102 m2 g−1 for BMG-c, and 997 m2 g−1 for BMG-h. With the heat treatment, there was an increase in specific surface area, and a decrease in oxygen contents. Herein, calcination was introduced to control the boron configuration. From the XPS survey spectra, the atomic composition of the BMG-h was C (70.6 at%), O (16.4 at%), and B (12.9 at%), while that of the BMG-c was C (73.3 at%), O (15.1 at%), and B (11.5 at%). From B1 s fitting analysis, BMG-h was dominant in the BCO 2 configuration. However, on heat treatment, BCO 2 peak reduction occurs during the thermal process, thus BC 2 O was prevalent in the graphene lattice of the BMG-c samples. We successfully controlled the specific surface area and configuration of boron in mesoporous graphene. BMG-h has more pseudo-capacitance behavior than BMG-c, because of the high boron and oxygen contents. Therefore, the control of porous structure and the boron configuration of BMG played an important role in providing the good specific capacitance of 336 F g−1 for the BMG-h, and 169 F g−1 for BMG-c, at a specific current density of 0.1 A g−1. Unlabelled Image • Hydrothermal synthesis of boron doped mesoporous graphene (BMG) using boric acid precursor. • The obtained BMGs show high specific surface area of 1102 m2 g-1 for BMG-c, and 997 m2 g-1 for BMG-h • The various boron configurations (BCO 2 and BC 2 O) contribute to electrochemical performance differently. • BMG electrodes exhibited enhanced specific capacitance, (336 F g-1 and 169 F g-1) for the BMG-h, and BMG-c, at a specific current density of 0.1 A g-1. [ABSTRACT FROM AUTHOR]

Li-ion batteries discover its way in developing new electrodes with recent advancements. In regardless, the new electrode materials necessity is to fulfill the high voltage operation with high current rate for Li-ion batteries. Hence, LiCo x V 2 O 5 (x = 0.1, 0.3 and 0.5) were synthesized by one pot hydrothermal synthesis followed by post calcination. The powder X-ray diffractometer explains the formation of LiCo x V 2 O 5 (x = 0.1, 0.3 and 0.5) with more than two phases as the cobalt concentration increases with increased grain size. FE-SEM and HR-TEM studies of the as-synthesized materials shows the formation of sphere and rod like morphologies. Cyclic voltammograms reveal an excellent redox peaks for Co and V, the redox peaks were observed between 2.0 and 4.5 V. LiCo 0.1 V 2 O 5 material delivered high reversible capacity of 147mAh/g especially at high current density as well as withstand stable discharge capacity up to 50 cycles. The charge-discharge cycling of LiCo 0.1 V 2 O 5 cathode materials at various rates 0.5C, 1C, 2C, 3C and 4C delivered specific discharge capacities of 147mAh/g, 129mAh/g, 113mAh/g, 98mAh/g and 85mAh/g with 96% columbic efficiency. Also it shows the lower charge transfer resistance with less interfacial properties, which contributed to the improved rate capability with stable cycling. Thus this material serves as promising cathode material for rechargeable Li-ion batteries. • One pot hydrothermal method gives rod and shape morphologies enhances the electrochemical properties. • LiCo 0.1 V 2 O 5 shows improve rate capability with stable and fast cycling. • It delivered high reversible capacity with long cycle life especially at high current rates. • Lower charge transfer contributed to the improved high rate capability with stable cycling. [ABSTRACT FROM AUTHOR]

Various metal-doped TiO 2 nanofibers were prepared by hydrothermal synthesis followed by the thermal treatment in air. An array of metal dopants including Ag, Au, Co, Cr, Cu, Fe, Ni, Pd, Pt, Y, and Zn, were respectively doped into TiO 2 NFs to acquire the visible-light photocatalytic activity. Considering the photodegradation results under visible-light illumination, Ag doped TiO 2 NFs was chosen to study further. Then, the optimal doping level and calcination process were studied systemically to obtain the highly visible light active Ag doped TiO 2 NFs. As the Ag doping concentration increased up to 5.00 mol%, anatase to rutile phase transition was observed. Meanwhile, based on the consistent results of synchrotron X-ray spectra, element analysis, and morphological observation, Ag 2 O was detected and located on the surface of as-synthesized Ag doped TiO 2 NFs. Thus, the photodegradation of methyl orange by using 5.00 mol%-Ag doped TiO 2 NFs calcined at 600 °C performed the highest visible-light photodegradation activity. Moreover, it also showed the excellent disinfection against E. coli and S. aureus under visible light due to the synergistic effect of Ag 2 O and photo-induced reactive oxygen species (ROS) formed by TiO 2 photocatalyst. The synthesized Ag doped TiO 2 NFs makes large-scale and convenient fabrication possible, and it has tremendous practical potentials in the photodegradation of environmental pollution and disinfects bacteria behavior. Unlabelled Image • Ag-TiO 2 NFs is synthesized by a single-step hydrothermal method. • Ag dopant promotes the phase transform to rutile/anatase mixing phase. • Ag 2 O precipitates on TiO 2 surface as doping concentration up to 5.00 mol%. • Ag-doped TiO 2 NFs shows great disinfection activity against E. coli and S. aureus. • Ag 2 O and photo-induced ROS contribute to the synergistic effect on disinfection. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are porous materials with highly ordered structures, and find application in various fields such as gas transportation and catalysis. In the present study, Al-based MOFs (MIL-96(Al)) were chosen as supports for α-MnO 2 because of their large specific surface area, excellent thermal stability, and environmental friendliness. Different loadings of α-MnO 2 (5%, 10%, and 15%) were anchored to MIL-96(Al) via a one-step process of hydrothermal synthesis, and all the samples were characterized by XRD, ICP-AES, SEM, TEM, and XPS. The results show positive synergistic effects between the reactants and the support. Structurally, α-MnO 2 is evenly dispersed on the surface of MIL-96(Al). Unlike common supports such as Al 2 O 3 and SiO 2 , MIL-96(Al) is not static during the process of loading. The reactant KMnO 4 modifies the surface of the support by destroying its organic ligands and forming erosion-induced holes, which help improve the dispersion of α-MnO 2. In terms of mercury removal, MIL-96(Al) exposes more active sites of α-MnO 2 by even dispersion of the latter, further enhancing the chemical adsorption and catalytic oxidation of α-MnO 2. The mercury removal efficiency of the sample MM-15 is 1.55 times that of pure α-MnO 2. XPS analysis was performed to determine the mechanism of Hg0 removal by α-MnO 2 -MIL-96(Al), and the capture agent was determined to be a combination of chemical adsorbent and catalyst. The Hg0 is oxidized to HgO by α-MnO 2 -MIL-96(Al), while Mn4+ is reduced to Mn3+, and α-MnO 2 can also catalyze the reaction between O 2 and Hg0. We believe that our research can introduce new avenues for effective understanding of the removal of heavy metals that threaten human health. Unlabelled Image • α-MnO 2 -MIL-96(Al) is more effective than pure α-MnO 2 for the removal of Hg0. • The synergistic effects between the reactants and the support are positive. • This capture agent is a combination of a chemical adsorbent and a catalyst. [ABSTRACT FROM AUTHOR]

Hierarchical porous α-Fe 2 O 3 /TiO 2 nanorod@core-shell microspheres were synthesized by a facile one-step hydrothermal approach without templates or surfactants. The as-obtained α-Fe 2 O 3 /TiO 2 nanorod@core-shell microspheres had an average diameter of 3.5 μm. Porous nanorods, with an average length of 1.5 μm, were randomly grown on the core-shell microsphere surfaces. The morphology, microstructure, and composition of the α-Fe 2 O 3 /TiO 2 heterostructures were characterized by various analytical techniques. Changes in the morphology and composition of the microspheres had an effect on the final gas sensing performance. Gas sensors based on the porous nanorod@core-shell α-Fe 2 O 3 /TiO 2 microspheres exhibited an excellent gas-sensing performance, with markedly enhanced responses in comparison with the pristine α-Fe 2 O 3 sensor. The response of the porous nanorod@core-shell α-Fe 2 O 3 /TiO 2 microspheres to 20 ppm acetone was approximately 34, which was 2.7 times higher than that of pure α-Fe 2 O 3 at 220 °C. Furthermore, the sensor could be easily recovered to its initial state following a short exposure to fresh air. The remarkably enhanced acetone-sensing performance was attributed to the unique porous nanorod@core-shell microsphere morphology, the strong interfacial interaction between TiO 2 and α-Fe 2 O 3 , and the presence of α-Fe 2 O 3 /TiO 2 heterojunctions. Thus, the prepared porous nanorod@core-shell α-Fe 2 O 3 /TiO 2 microspheres sensors showed an outstanding performance in acetone detection. • Novel sphere/rod-like α-Fe 2 O 3 /TiO 2 were synthesized using a facile hydrothermal method without templates or surfactants. • Gas sensors based on α-Fe 2 O 3 /TiO 2 microspheres exhibited excellent gas sensitivity comparison with the pristine α-Fe 2 O 3 sensor. • The strong interfacial interaction between TiO 2 and α-Fe 2 O 3 can enhance acetone-sensing performance. [ABSTRACT FROM AUTHOR]

The ternary complex photocatalysts of BiOIO 3 /g-C 3 N 4 /MoS 2 by solvent-exfoliation method was synthesized for the first time. In the typical procedure, the BiOIO 3 /g-C 3 N 4 was obtained via hydrothermal synthesis technique, and then the BiOIO 3 /g-C 3 N 4 /MoS 2 photocatalysts were prepared via ultrasonic solvent-exfoliation method from bulk commercial MoS 2 in the alcohol solution. The samples of BiOIO 3 /g-C 3 N 4 /MoS 2 were analyzed by PL, XRD and other characterization analysis methods. The photocatalytic activity of the as-prepared samples was investigated by removing gas phase mercury irradiation under visible light. The as-prepared BCM-0.3 exhibits excellent photocatalytic performance, being with the highest efficiency of 70.58%. Owing to the electronic channels of field-effect, an internal electric field was formed through the corresponding band-gap engineering, improving photocatalytic reaction. Besides, the excellent activity of the ternary photocatalysts BiOIO 3 /g-C 3 N 4 /MoS 2 is attributed to heterostructure between BiOIO 3 /g-C 3 N 4 and MoS 2 , which enlarges spectral response and improved separation efficiency of charge carriers, and MoS 2 -composing, which provides more active sites for catalytic oxidation. In addition, the as-prepared samples with excellent photocatalytic performance also offer a perspective insight into the hydrogen evolution, CO 2 conversion and degradation of organic pollutants. • The ternary compound photocatalyst of BiOIO 3 /g-C 3 N 4 /MoS 2 by solvent-exfoliation method was synthesized for the first time. • The as-prepared ternary nanocomposite exhibits more excellent photoactivity compared with BiOIO 3 /g-C 3 N 4. • The possible photoinduced charges transfer mechanism and photocatalytic reaction mechanism were proposed. [ABSTRACT FROM AUTHOR]

Carbonate intercalated layered Zn, ZnNi and ZnCu hydroxides were synthesized by a facile hydrothermal method for the visible light driven photocatalytic methylene blue dye degradation. The crystalline phase, surface states, optical and morphological properties were studied by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) measurements. The XRD measurement demonstrated that all the synthesized materials were in a regular layered structure. Optical spectra of the samples were revealed that layered ZnNi hydroxide showed the visible light absorption property. The photocatalytic activities of the prepared layered materials examined by the degradation of methyl blue (MB) dye solution under visible light illumination. Among the prepared layered hydroxide, ZnNi hydroxide exhibited the 90% removal rate for MB under visible light illumination. The enhanced photocatalytic activity of ZnNi hydroxide is due to combined visible light absorption nature and hierarchical flower-like structure with a large number of active sites. Moreover, the ZnNi hydroxide has very good recyclability until remain active after the complete fourth degradation cycle. Unlabelled Image • Carbonate intercalated layered hydroxides were prepared by hydrothermal method. • ZnNi layered double hydroxide showed the highest dye degradation activity under visible light illumination. • The enhanced photocatalytic activity of ZnNi layered double hydroxide is due to visible light absorption nature [ABSTRACT FROM AUTHOR]

Abstract Tungsten oxide has attracted considerable attention as a typical photochromic material. Herein, a simple route for the synthesis of tungsten oxide quantum dots (WO 3-x QDs) was demonstrated which was accomplished by the hydrothermal treatment of ammonium tungstate hydrate in the present of polyvinyl pyrrolidone (PVP). This photochromic material can rapidly undergo a color change reaction under the irradiation of ultraviolet or solar light. More importantly, the bleaching can be completed in a dark environment for 5 min and the cycle stability is excellent. The ultra-small size, existence of oxygen deficiency, and the surface modification by PVP are attribute to fast photochromic performance, excellent reversibility and cycling stability of WO 3-x QDs. Highlights • Tungsten oxide quantum dots were synthesized via a facile hydrothermal method. • The surface modification serves to improve the reversibility and cyclability of the materials. • This photochromic material can rapidly undergo a color change reaction under UV light irradiation. • The aqueous dispersion of WO 3-x QDs showed excellent reversibility and cycling stability. [ABSTRACT FROM AUTHOR]

Abstract Bismuthoxyhalides photocatalysts (BiOX, X = Cl, Br, I) were prepared using solvothermal crystallization method. The influence of the synthesis temperature (120 °C, 140 °C, 160 °C) and duration (3 h, 24 h, 48 h) on the structural (crystal size, phase composition etc.), morphological (crystal shape), optical (bandgap values) parameters and on the resulting photocatalytic activity were investigated. The samples were characterized by the means of X-ray diffractometry (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the synthesized materials was evaluated under visible- (≥ 400 nm) and UV light (≈ 365 nm) by degrading methyl orange and Rhodamine B (RhB). The results pointed out the importance of the crystallization temperature and duration in achieving the highest photocatalytic activity, showing that the lowest temperature and the shortest duration time resulted the highest removal yields. Furthermore, a possible degradation mechanism was elaborated based on a direct hole oxidation approach and the detected degradation intermediates. Graphical abstract Unlabelled Image Highlights • The hydrothermal crystallization time tunes the efficiency of BiOX photocatalysts. • High synthesis temperature (160 °C) resulted Bi0, which inhibited the photoactivity. • The degradation products were identified, and direct hole oxidation mechanism was suggested. • The UV and the visible light degradation mechanism result different intermediate products. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A facile microwave-assisted method grows CuO nanocrystals on rGO nanosheets uniformly. • CuO@rGO nanocomposites are selectively response to H 2 S at low temperatures. • The amounts of CuO nanocrystals highly influence their H 2 S-sensing properties. • The synergistic effect of CuO and rGO species enhances the H 2 S-sensing property. Abstract Hierarchical CuO@rGO nanostructures, consisting of CuO nanoparticles (NPs) and reduced graphene oxide (rGO) nanosheets, were prepared with a normal-pressure microwave-assisted in-situ growth process. In the CuO@rGO composites, CuO NPs with a size range of 4–11 nm are uniformly anchored on rGO surfaces. In contrast, CuO particles of large and non-uniform distribution in the CuO-doped rGO nanosheets (CuO/rGO) were prepared by a conventional hydrothermal method. The CuO@rGO sensors show high response and selectivity to H 2 S (1–10 ppm) at low operating temperatures (50–150 °C). The mass ratio of copper acetate to graphene oxide during preparation (6–10) is found to highly influence the gas-sensing properties, and the 8-CuO@rGO sample shows the highest H 2 S-sensing performance at 100 °C. Compared with pristine CuO nanocrystals, the 8-CuO@rGO composite exhibits considerably enhanced gas-sensing performance, such as good response, high selectivity and low optimal temperature. The improved H 2 S-sensing performance of the CuO@rGO composites can be attributed to the synergistic effect in components and their hierarchical nanostructure. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • La-doped p-type ZnO (La:ZnO) NWs were synthesized by a hydrothermal method. • Their physical and chemical properties are systemically investigated. • La-doping can improve piezoelectric performance by electron screening effect. • La:ZnO nanogenerators are good candidates for power sources in electronic devices. Abstract In recent years, energy harvesting has attracted considerable attention as a promising method to convert waste energy to useful energy. In particular, piezoelectric energy harvesters are of significant interest, because they have a simple structure and can be used to harvest energy regardless of weather or other environmental conditions. In accordance with the miniaturization trend of electronic devices driven by low power, piezoelectric nanogenerators (PENGs) using various nanostructured materials are being developed. Among them, ZnO nanowires (NWs) are most widely used for the use of PENGs. However, while research on n-type ZnO NWs is extensive, studies on p-type ZnO NWs are insufficient owing to their poor stability. In this study, La-doped p-type ZnO (La:ZnO) NWs were synthesized by a hydrothermal method to expand the applications of p-type ZnO and determine their potential as PENGs. XRD analysis showed that La3+ ions was well doped without the formation of any secondary phases and caused a change in the lattice parameter when compared to that of undoped ZnO. XPS analysis was performed to investigate the surface elemental compositions of La:ZnO NWs, and the morphology of La:ZnO NWs was investigated using SEM and TEM. We further studied the piezoelectric output performance of undoped and La-doped ZnO NWs, and found that La:ZnO NWs showed improved piezoelectric output performance as a result of electron screening effect of the p-type semiconductor. [ABSTRACT FROM AUTHOR]

Highlights • Proposed an effective hydrothermal phosphatization method with a new phosphorus source. • Prepared NiCoP/NF electrodes with enhanced area capacitance. • Synthesized Fe x PO y /IF electrode as a potentially candidate for anode. • Assembled a battery-supercapacitor hybrid device. Abstract It is a challenge to build a hybrid energy storage system by combining the power of supercapacitors with the energy of batteries. In this work, an effective and promising phosphatized method using aluminium phosphide as phosphorus source was proposed to prepare metal phosphides. The introduction of water vapor in phosphatized process not only participates in the reaction, but also accelerates the etching and phosphatization of electrode, which promotes the formation of characteristic architecture. Then, NiCo and Fe-based electrodes were synthesized through hydrothermal phosphatization. The NiCoP/nickel foam (NiCoP/NF) electrodes which have favorable electrochemical performance at high current densities achieved a high areal capacity (19.90 F cm−2 at 50 mA cm−2) and favorable cycling stability (capacity retention of 92% at a high current density of 50 mA cm−2 after 2000 cycles). Furthermore, we successfully built NiCoP/NF//Fe x PO y /IF battery-supercapacitor hybrid system with advanced electrochemical performance. The device possesses a high areal capacity of 6.28 F cm−2, a maximum volumetric energy density of 56.11 mW h cm−3 and power density of 0.642 W cm−3. These results confirm that the phosphatized method is promising for the preparation of metal compounds, and the battery-supercapacitor hybrid system effectively combine the merits of supercapacitors and batteries, indicating the Fe-based electrode as a potentially candidate for next generation anode for hybrid systems. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • GdPO 4 hierarchical hollow spheres were fabricated via a template-directed approach. • The phase structure, morphology, and formation process were investigated in detail. • The sample reveals good biocompatibility, high drug loading capacity and sustained release patterns. • The sample exhibits multimodal imaging functionality for combined optical and MRI. • The samples may be applied in drug delivery, cell imaging, and disease diagnosis. Abstract Well-defined GdPO 4 hierarchical hollow spheres have been synthesized via a novel template-directed synthesis approach with 3-aminophenol-formaldehyde resin spheres as template. The core-shell structured precursor was firstly prepared by a homogeneous precipitation and subsequent hydrothermal route. Finally, the GdPO 4 hollow spheres were obtained after an annealing process in air. The phase structure, morphology, and formation process were also investigated in detail. Moreover, the as-synthesized GdPO 4 hollow spheres show good biocompatibility and excellent drug loading and sustained drug release ability. Interestingly, the lanthanide activator ions doped GdPO 4 hollow spheres exhibit multimodal imaging functionality for combined optical and magnetic resonance imaging (MRI). Due to the well-defined hollow structure, good biocompatibility, luminescence properties, positive magnetic signal-enhancement ability, and drug loading/release patterns, the as-obtained GdPO 4 samples may be potentially applied in fields of bioimaging, drug delivery, and disease diagnosis. Furthermore, this novel synthetic strategy may pave a critical way for the preparation of other similar lanthanide orthophosphate functional materials with perfect hollow spherical structure, tunable particle sizes, and good physicochemical properties. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Urchin-like hollow sphere shaped ZnSn(OH) 6 particles were synthesized by 2-step hydrothermal method. • Zn 2 SnO 4 /SnO 2 phase were obtained by annealing process at 800 °C. • Rod-shaped SnO 2 were located outside of hollow sphere. • We conducted photocatalyst and quartz crystal microbalance (QCM) experiments. Abstract In this paper, we successfully synthesized urchin-like hollow sphere shaped ZnSn(OH) 6 by a 2-step hydrothermal synthesis process. During the synthesis process, the sphere shape was used as a template and formed based on Pearson's hard and soft acid and base (HSABs) theory. The rod shape on the outside of sphere is SnO 2 , it was characterized by energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Raman spectrum. The crystal phase of ZnSn(OH) 6 with different shape changes to Zn 2 SnO 4 /SnO 2 through annealing process at 800 °C. Finally, we measured photocatalyst and quartz crystal microbalance (QCM) based on the advantages of composite material and morphology-modulation. As a result, urchin-like hollow sphere shaped Zn 2 SnO 4 /SnO 2 achieved the best efficiency in all applications. [ABSTRACT FROM AUTHOR]

Highlights • Boron doped LiZr 2 (PO 4) 3 Li-ion electrolyte has been achieved via hydrothermal synthesis. • Boron doping mainly happens on the Zr-site of Li 1+x Zr 2-x B x (PO 4) 3. • Rietveld refinement confirmed phase purity can be up to x = 0.05 in Li 1+x Zr 2−x B x (PO 4) 3. • Phase transition undergoes from triclinic to rhombohedral if heated from 25 to 100 °C. Abstract Boron doped LiZr 2 (PO 4) 3 electrolyte was successfully synthesized via facile hydrothermal synthesis. Our results show that boron doping mainly happens on the Zr-site of Li 1+x Zr 2-x B x (PO 4) 3 not the P-site of Li 1+6x Zr 2 (P 1−x B x O 4) 3. Rietveld refinement of the unit-cell parameters was performed, and it was verified by consideration of Vegard's law that it is possible to obtain phase purity up to x = 0.05 in Li 1+x Zr 2−x B x (PO 4) 3. This corresponds with phases present in the XRD data, which shows the additional presence of the low temperature (monoclinic) phase for the powder sintered at 1200 °C for 12 h of compositions with x ≥ 0.075. The compositions inside the solid solution undergo the phase transition from triclinic to rhombohedral when heating from 25 to 100 °C. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • NiMoO 4 nanorods have been synthesized via facile and scalable hydrothermal route. • Time and temperature have been optimized for best electrochemical properties. • Specific capacitance of 594 F/g has been obtained for optimized NiMoO 4 electrode. • NiMoO 4 //activated carbon asymmetric supercapacitor device has been fabricated. • An energy density of 18 Whkg−1 and power density of 704 Wkg−1 have been achieved. Abstract NiMoO 4 nanorods of different properties were synthesized via facile and scalable hydrothermal route by varying the reaction time and temperature and the effect of synthesis parameters on their electrochemical performances was investigated. Optimization of the synthesis parameters was carried out based on the electrochemical performance. Experimental analysis revealed that NiMoO 4 nanorods synthesized at 150 °C for 6 h showed optimum electrochemical performance with specific capacitance, as high as 594 Fg−1 at 1 Ag−1 current density due to greater mesoporous nature and optimum crystallinity index. NiMoO 4 //activated carbon asymmetric supercapacitor device was fabricated using the optimized NiMoO 4 nanorods and characterized for the electrochemical performances. Specific capacitance of 66 Fg−1 was obtained for the fabricated supercapacitor device at 1 Ag−1 current density and 56% retention of the specific capacitance was observed after 1000 cycles. An energy density of 18 Whkg−1 and power density of 704 Wkg−1 were achieved at 1 Ag−1 current density which offer great promise for supercapacitor application of this material. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Cs-doped α-Bi 2 O 3 has been successfully synthesized by hydrothermal process. • Undoped and Cs-doped α-Bi 2 O 3 has a crystallographic phase of monoclinic form. • Cs-doped α-Bi 2 O 3 formed in microplates with high crystallization. • Cs-doped α-Bi 2 O 3 microplates are superior to that of undoped α-Bi 2 O 3. Abstract Cs-doped α-Bi 2 O 3 was synthesized via a facile hydrothermal reaction. The phase formations of the samples were investigated via X-ray powder diffraction (XRD) patterns and structural refinements. The samples present well-crystalized microplates with smooth surfaces and a thickness about 300 nm. The experiments revealed that the undoped and Cs-doped α-Bi 2 O 3 microplates could crystallized in a pure monoclinic phase. The band gap of α-Bi 2 O 3 could be reduced via the Cs-doping in the lattices. The photocatalytic activity on photo-degradation of methylene blue (MB) was significantly improved with the Cs-doping. The effective photocatalysis was discussed on the improved visible-light response, the enhanced dispersion in the valence band composed of hybrid orbitals of Bi6s, O2p and Cs3d, and the lowered electron–hole recombination. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The rHGO-decorated NiCo 2 O 4 nanowires were constructed on carbon fibers. • The rHGO/NiCo 2 O 4 @CF exhibited hierarchical interpenetrating network structure. • The rHGO enhanced the electrochemical properties of rHGO/NiCo 2 O 4 @CF. • The rHGO/NiCo 2 O 4 @CF//AC supercapacitor delivered excellent performance. Abstract The hierarchical interpenetrating reduced holey graphene oxide (rHGO)-decorated NiCo 2 O 4 nanowires were constructed on carbon fibers (rHGO/NiCo 2 O 4 @CF) by a hydrothermal synthesis. Benefiting from the abundant nanopores and good conductivity of rHGO, the rHGO/NiCo 2 O 4 @CF delivered excellent specific capacitance of 1178 F g−1 at 1 A g−1 as supercapacitor electrode and outstanding rate capability of 93.4% capacitance retention even at 10 A g−1. Furthermore, an asymmetric supercapacitor by using rHGO/NiCo 2 O 4 @CF as the positive electrode and activated carbon as the negative electrode has been assembled, which exhibited a high energy density of 74.88 Wh kg−1 with a power density of 799.9 W kg−1 and good cycle stability (82.7% capacitance retention after 5000 cycles). These exciting results are attributed to the hierarchical porous interpenetrating network architecture and the synergistic effect between rHGO and NiCo 2 O 4 nanowires. [ABSTRACT FROM AUTHOR]

Highlights • NiAl-layered double hydroxides are grown on Si substrate by hydrothermal method. • Growth mechanism of the NiAl-layered double hydroxides is investigated. • Band gap energy of the NiAl-layered double hydroxide is found to be 4.15 eV. Abstract We report on the growth mechanism of NiAl-based layered nanostructures on rigid substrates using a low-temperature hydrothermal method. NiAl-layered double hydroxide (LDH) structures were grown with various source concentrations and growth times. Structural and optical investigations showed that uniform NiAl-LDHs were grown on the substrates because Al(OH) 3 was sufficiently supplied from the aluminum thin film seed layer when the Ni source concentration was low and in the initial stage of the growth. However, a bilayer of NiAl-LDH and α-Ni(OH) 2 was formed when the Ni sources were sufficiently supplied and the growth time was long enough because of the deficient Al(OH) 3 sources at the growth front. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • TiO 2 nanocrystals terminated with predefined facets were synthesized hydrothermally. • Nanorods, nanocubes and nanosheets of TiO 2 were covered with Fe 2 O 3 nanoparticles. • TiO 2 @Fe 2 O 3 represents a multicomponent heterostructure with Fe-doped TiO 2. Abstract TiO 2 nanocrystals with well-controlled facets were synthesized using a hydrothermal method. Decreasing concentration of the bridging ligand allowed us to modify the morphology and shape in a sequence nanorods → nanocubes → nanosheets. The co-precipitation was used to cover TiO 2 nanocrystals with Fe 2 O 3 nanoparticles. Transmission Electron Microscopy TEM, Scanning Electron Microscopy SEM, X-ray diffraction XRD, Raman spectroscopy, electrophoretic light scattering ELS and optical spectrophotometry in uv/vis/nir ranges were applied for materials characterization. Band diagram, consisting of three-component heterojunction, was proposed based on the calculations of optical transitions between valence and conduction bands of TiO 2 @Fe 2 O 3 determined from the analysis of the reflectance spectra. The acceptor-type energy level (0.38–0.46 eV above the top of TiO 2 valence band) was attributed to trivalent iron ions incorporated into the titanium sub-lattice. [ABSTRACT FROM AUTHOR]

Highlights • CdS-MoS 2 -MXene composites were prepared via a simple hydrothermal method for the first time. • The composites exhibited greatly enhanced photocatalytic hydrogen evolution rate. • The synergetic effect of MoS 2 and Mxene contributed to the high activity. Abstract Water splitting under visible light irradiation over earth-abundant, inexpensive and high active catalysts is an effective and direct way to obtain renewable H 2 energy. Here, a kind of novel noble-metal-free composite photocatalyst with high hydrogen evolution performance was synthesized by a simple hydrothermal method. In the composite, MXene slice with excellent conductivity was used to promote the activity of CdS-MoS 2 catalyst. A prominent H 2 generation rate of 9679 μmol⋅g−1⋅h−1 for the ternary composite was obtained under the irradiation of visible light (λ ≥ 420 nm). It exhibited a great enhancement by a factor of 251.3% in comparison with CdS-MoS 2. The exceptional performance of CdS-MoS 2 -MXene was mainly arised from the high carrier mobility of MXene, which facilitates the separation of photoinduced electron-hole pairs. The present findings would provide a new direction towards exploring MXene-based composite photocatalysts with high photocatalytic performance in water splitting. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The NAHT of AC significantly increases its NOCO activity by ca. 85.0%. • The NAHT of AC leads to altering micropore size and N-doping simultaneously. • The 0.6–0.7 nm micropores and surface basicity of AC determine NO conversion. • The long stability of AC after NAHT ensures it with the ability of continuous NOCO. Abstract The nitric acid hydrothermal treatment (NAHT) of activated carbon (AC) was performed to greatly improve its activity of NO catalytic oxidation (NOCO) at room temperature by simultaneously altering pore size and N-doping. The activity was increased from 30.6% to 56.6% with the optimal nitric acid amount of 1.6 mL. Under this condition, the catalyst exhibited a more than 400 h stability, which is promising for a continuous NO removal. Characterization including SEM, TEM, XRD, Raman spectroscopy, N 2 adsorption/desorption, elemental analysis, H 2 -TPR, FT-IR, in-situ DRIFTS, and XPS revealed that micropore distribution in 0.6–0.7 nm was increased and N-containing functionalities like pyridinic, pyrrolic and quaternary N were introduced to AC surface by NAHT, both of which contributed to the promotion of NOCO activity. The mechanism of NOCO by AC after NAHT was proposed, including the nanoreactor effect of micropores and NO adsorption controlled by surface basicity. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Al 2 O 3 with porous surface structure and hydrophilic surface was fabricated. • Nano-rod-like HA coatings were obtained on Al 2 O 3 via hydrothermal synthesis. • The highest bonding strength of HA coatings on porous Al 2 O 3 is 18.3 ± 2.4 MPa. • HA crystals nucleate on the inwall of pores, epitaxially grow and cover on Al 2 O 3. • HA coated-Al 2 O 3 has excellent biological activity in vitro. Abstract Due to excellent mechanical properties and biocompatibility, A1 2 O 3 is considered as a promising biomaterial for biomedical applications. However, the inherent bio-inertness of A1 2 O 3 have limited its wider application. Although applying bioactive hydroxyapatite (HA) coatings on Al 2 O 3 is an effective method to improve surface bioactivity, the bonding strength between the HA coatings and the flat A1 2 O 3 substrate is low. In this study, Al 2 O 3 with micro-porous surface structure and hydrophilic surface was fabricated by anodic oxidation to improve the bonding strength between HA coatings and Al 2 O 3. Then, strong-bonding HA coatings were prepared on the porous Al 2 O 3 by hydrothermal synthesis. The results reveal the uniformity of pore distribution and the wettability of Al 2 O 3 surface are significantly improved with the increase of current density and oxidation time. When the porous Al 2 O 3 is prepared by anodic oxidation at 7 mA/cm2 for 4 h, the diameter of pores is 4.3–7.1 μm and the porous Al 2 O 3 has a contact angle of 42.2 ± 2.6°. Nano-rod-like HA coatings completely and uniformly cover the surface of Al 2 O 3 by hydrothermal synthesis at 180 °C for 24 h. The thickness of HA coatings is almost 30 ± 1.01 μm without delamination and/or cracking at the interface between HA coatings and Al 2 O 3. The highest bonding strength of HA coatings on porous Al 2 O 3 is 18.3 ± 2.4 MPa, which is higher than that of HA coatings formed on flat Al 2 O 3 by other methods. In addition, simulated body fluid (SBF) immersion tests indicate that HA-coated Al 2 O 3 possesses excellent biological activity in vitro. Hence, Al 2 O 3 with bioactive HA coatings could be a candidate biomaterial for biomedical applications. [ABSTRACT FROM AUTHOR]

Highlights • Two–dimensional g–C 3 N 4 /α–AgAl 0.4 Ga 0.6 O 2 p–n heterostructure is synthesized by phase transition under hydrothermal treatment. • Similar morphology of two phases yields large and close interfaces. • Improved photocatalytic and photoelectrochemical properties are attributed to efficient heterojunction. Abstract Design and preparation of two–dimensional heterostructure is an effective strategy to obtain enhanced photoelectrochemical and photocatalytic performances. Herein, two–dimensional g–C 3 N 4 /α–AgAl 0.4 Ga 0.6 O 2 p–n heterostructure is for the first time synthesized by phase transition method under hydrothermal treatment. It is found that the heterostructure shows the coexistence of two phases with high crystallinity. Platelet-like α–AgAl 0.4 Ga 0.6 O 2 and g–C 3 N 4 sheets couple each other face to face, resulting in the formation of close interfaces and efficient heterojunctions. UV–vis absorption of the heterostructure is modulated efficiently by controlling the phase component. When utilized as photocatalysts for MO degradation under visible light irradiation, the g–C 3 N 4 /α–AgAl 0.4 Ga 0.6 O 2 with a molar ratio of 0.75 exhibits the most excellent photocatalytic performance with a rate constant of 0.0227 min−1. The further investigation of the photoelectrochemical property including small diameter of the arc radius and maximum photocurrent indicates that the separation efficiency of electron–hole pairs is greatly improved through heterojunctions with two–dimensional coupling interfaces. Besides, the reaction kinetics and the photocatalytic mechanism related to the energy band are proposed for degrading organic pollutants. The results prove that the g–C 3 N 4 /α–AgAl 0.4 Ga 0.6 O 2 heterostructure has great potential application in photocatalysis for eliminating organic pollutants. [ABSTRACT FROM AUTHOR]

Highlights • Facilely and cost-effectively synthesis of carbon quantum dots (CQDs) based on simply hydrothermal treatment of lignin. • A novel switchable fluorescence nanosensor for Fe3+ ion and ascorbic acid. • Determining Fe3+ and AA in human biological samples by the prepared materials. • Cellular imaging and detecting Fe3+ and AA in bio-system by the proposed sensing platform. Abstract A facile and cost-effective route of fabricating carbon quantum dots (CQDs) was proposed via simply hydrothermal treatment of lignin. Because of abundant aromatic structure and functional groups derived from lignin, the prepared CQDs (LCQDs) showed unique chemical and optical property. A remarkable fluorescence quenching effect of Fe3+ on LCQDs was found, resulting from the formation of non-fluorescence complex between LCQDs and Fe3+. This "on-off" fluorescence CQDs nanoprobe for Fe3+ allowed a wide linear range of 50–650 μM with the limit of detection (LOD) as low as 196 nM. Besides, ascorbic acid (AA) was found to reduce Fe3+ to Fe2+, leading to the recovery of the LCQDs fluorescence and a good linearity in range of 0–350 μM with a LOD of 5.34 μM. Furthermore, this sensing platform was successfully used for Fe3+ and AA monitoring in biological samples and intracellular imaging without surface modification. [ABSTRACT FROM AUTHOR]