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[Display omitted] In recent years, the research on intrinsically safe aqueous zinc-ion batteries (AZIBs) has gained significant attention. However, the commercialization of AZIBs is hindered because of the formation of dendrites in them and undesired hydrogen evolution reaction (HER) at their anode. MXene is a promising two-dimensional material that can inhibit dendrite growth and undesired HER at the anode when used as a protective layer for the anode in AZIBs. MXene's surface functional groups play a crucial role in this protective function. However, the working mechanisms of these surface functional groups have not been thoroughly understood. Based on first-principles calculations and molecular dynamics simulation, we investigated the mechanisms of MXene with nine surface functional groups, including oxygen and halogen elements, as an anode protection layer. We checked their structural stability, electronic structure, adsorption energy, HER reaction free energy, Zn2+ diffusion energy barriers, coordination number of Zn2+- H 2 O and diffusion coefficients of Zn2+. The MXene species with -S and -O functional groups exhibit good electrical conductivity and greatly adsorb Zn2+. Conversely, MXene species with halogen-functional groups significantly inhibit HER reactions. MXene materials with -Se functional group have the best desolvation effect (ΔCN = 0.31), while those with -I end group have the fastest ability to diffuse zinc ion. This research provides a theoretical guidance for the design of MXene based anode protection layers, which can help to develop dendrite-free and low side-reaction AZIBs. [ABSTRACT FROM AUTHOR]

Carbon-based quantum dots (QDs), as a new type of zero-dimensional (0D) inorganic material, are favored by researchers because of their superior optical properties, good water solubility, and biocompatibility. Besides graphene QDs (GQDs), many new carbon-based QD materials with good quality and excellent performance have emerged in recent years, such as g-C3N4 QDs (CNQDs), MXene QDs (MQDs), and graphdiyne QDs (GDQDs). These carbon-based QDs will open up unprecedented new opportunities in the fields of materials science, energy and environmental photocatalysis. Regrettably, a comprehensive review of the relevant topics is lacking. This review focuses on the applications of emerging carbon-based QD materials in sustainable photocatalysis. Herein, the structural characteristics of carbon-based QDs are first depicted. On this basis, the preparation, modification, and photocatalytic mechanism of high-quality carbon-based QDs are comprehensively summarized. Subsequently, the latest research progress on typical carbon-based QDs in the field of sustainable photocatalysis is discussed categorically. Finally, the future developments and challenges of highly active carbon-based QDs are proposed insightfully. This review is expected to provide powerful scientific guidance for the design, fabrication, and application of carbon-based QD materials. [ABSTRACT FROM AUTHOR]

Research on 2D materials has recently become one of the hottest topics that has attracted broad interdisciplinary attention. 2D materials offer fascinating platforms for fundamental science and technological explorations at the nanometer scale and molecular level, and exhibit diverse potential applications for future advanced nano-photonics and electronics. The chemical vapor deposition (CVD) technique has shown great promise for producing high-quality 2D materials with superior electro-optical performance. However, it is difficult to synthesize continuous single-crystal 2D materials with large domain sizes and good uniformity due to the low vapor pressure of their precursors. It has been observed that the addition of selected synergistic additives to the CVD process under mild conditions can result in uniformly large-area and highly crystalline monolayer 2D materials with exceptional optical/electrical properties. Moreover, the 2D material-based devices chemically modified by synergistic additives can achieve superior performances compared to those previously reported. In this review, we compare several typical synergistic additive-mediated CVD growth processes of 2D materials, as well as their superior properties, and provide some perspectives and challenges for the future of this emerging research field. [ABSTRACT FROM AUTHOR]

The Co 3 O 4 /g-C 3 N 4 heterojunctions were prepared by a facile one-pot thermal decomposition technique. Compared with g-C 3 N 4 , it was found that Co 3 O 4 /g-C 3 N 4 heterojunctions possessed a higher Brunner-Emmet-Teller (BET) surface area, which was beneficial to the diffusion of aim molecules on the electrode surfaces. And the optimal Co 3 O 4 /g-C 3 N 4 heterojunctions exhibited a narrower band gap and a higher donor density, resulting in an excellent electrocatalytic activity for environmental phenolic hormones. Moreover, the Co 3 O 4 /g-C 3 N 4 heterojunctions were used for the electrochemical sensing of environmental phenolic hormones such as bisphenol A, pentachlorophenol, p -nitrophenol and octylphenol. All detection ranges reached three orders of magnitude, showing a lower limit of detection of 10 −9 mol L −1 . So, sensitivity and accurate determination of environmental phenolic hormones in real water samples may use this Co 3 O 4 /g-C 3 N 4 heterojunctions modified electrode. [ABSTRACT FROM AUTHOR]

Volcanic ash is frequently referenced as natural particles, yet few applications for wastewater purification and surface-enhanced Raman scattering (SERS) have been reported. Here, a unique micro/nanostructured nozzle-shaped volcanic ash was characterized. The natural volcanic ash had an ordered porous structure with an average diameter of 20 µm. Macropores with 200-nm pore size and 3–5-nm mesopores were homogeneously distributed on the surface of the volcanic ash. The volcanic ash provided an efficient water purification for simulated dye and livestock wastewater. The volcanic ash/silver nanoparticle hybrid also exhibited strong SERS. Moreover, the differing adsorption sequence of silver nanoparticles and probes on the surface of volcanic ash created distinctive enhancements. The micro/nanostructured volcanic ash was shown to be a promising water purifying agent and platform for SERS in environmental monitoring. [ABSTRACT FROM AUTHOR]

Volcanic ashes (VA) are often referenced as examples for natural particles, yet the application in sensors is only rarely documented. Here, a unique kind of micro/nano-structured shower-nozzle-like VA was explored. The natural VA showed an ordered porous structure with an average diameter of ca. 20 μm, and it was constituted by regular ca. 200 nm macroporous and ca. 4 nm mesoporous. The surface enhanced Raman scattering (SERS) activity of the VA was investigated by using crystal violet (CV) as a probe. It was found that shower-nozzle-like VA itself possessed a certain SERS response. Moreover, the VA/Ag nanoparticles hybrid exhibited a strong SERS enhancement effect with an enhancement factor of 8×10 8 . Meanwhile, cyclic voltammetry was applied to investigate the electrochemistry performance of the VA-dopamine-glassy carbon (VA-DA-GCE) modified electrode. It was found that the VA possessed high electrocatalytic activity to octylphenol. This good analytical performance makes micro/nano-structured shower-nozzle-like VA as promising SERS or electrochemical sensor for the detection of trace organic pollutants. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) substrates with high SERS activity and stability are important for SERS sensors. A facile method was developed to fabricate efficient and stable SERS substrates by combining Ag nanoparticles (NPs) and micro-scale sheeted graphitic carbon nitride (g-C 3 N 4 ). The g-C 3 N 4 /Ag NPs hybrid could provide a great number of hot spots and concentrated the analyte by the π–π stacking interaction between analyte molecules and g-C 3 N 4 , making a dramatic Raman enhancement. Moreover, the g-C 3 N 4 /Ag NPs hybrid uniformly immobilized Ag NPs on the surface and edges of g-C 3 N 4 sheets by an interaction between Ag NPs and g-C 3 N 4 , leading to much improved long-term stability. This could be explained in terms of the electron–donor effect of g-C 3 N 4 , which was further confirmed by density functional theory calculations. The inherent Raman enhancing effect of g-C 3 N 4 itself also contributed to the total SERS responses. Due to multiple enhancement contributions, the g-C 3 N 4 /Ag NPs hybrid exhibited a strong Raman enhancement effect for with an enhancement factor of 4.6 × 10 8 (evaluated by using crystal violet as a probe), and possessed wide adaptability from dyes, pesticides to bio-molecules. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C 3 N 4 ) has attracted worldwide attention, because of its promising potential applications and theoretical prediction of its unique properties. Herein, 1-, 2- and 4-layer g-C 3 N 4 nanosheets were synthesized in a well-crystallized form by controlling the intercalation time in a simple intercalation–exfoliation process. The electronic structures of the nanosheets were captured in their Raman spectra that clearly evolved with the layer number of the nanosheets for the first time. A clear correlation between the spectral properties and the layer number of the nanosheets was clarified by combining Raman spectra and the first-principles calculations. Raman vibrational modes of g-C 3 N 4 were assigned. The layer–layer deformation vibrations and related in-plane twisting vibrations or symmetrical stretching vibrations reflected the change in the electronic structure of the nanosheets with different layers. The results may shed light on brand-new opportunities for significant improvements in the synthesis, structure, electronic and optical properties of single-layer and ultrathin g-C 3 N 4 nanosheets toward desirable functional materials. [ABSTRACT FROM AUTHOR]

Abstract: β-In2S3 with 3D chrysanthemum-like superstructures has been successfully synthesized by a simple surfactantfree hydrothermal route. It was found that the effect of reaction temperature, sulfur source and solvent on the morphology and structure of In2S3 microspheres was obvious. The crystallization, morphology and composition of as-prepared β-In2S3 were characterized by XRD, SEM, Raman and EDS, respectively. It revealed that 3D chrysanthemum-like β-In2S3 was built from small 2D nanosheets with thickness of 40nm. Differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were applied to investigate the electrochemistry performance of product. It was found that the synthesized 3D chrysanthemum-like β-In2S3 possessed the high electrocatalytic activity. [Copyright &y& Elsevier]

Abstract: Wafer-like paramagnetic BiFeO3 were successfully fabricated via hydrothermal route without any dispersant or mineralizer. The obtained samples exhibited a rhombohedral single-phase and a narrow band gap of 2.05 eV. Its catalytic activity was investigated and it was found that the degradation efficiency of 10 mg L−1 Rhodamine B was above 90.5% over 1.0 g L−1 BiFeO3 within 10 mmol L−1 H2O2 at pH 5.7 and temperature 25 °C in 3 h under the visible-light irradiation. It was revealed that BiFeO3 possessed excellent reusability. The modified electrode of synthesized BiFeO3–chitosan–glassy carbon electrode could dramatically enhance the peak current in 1 mM K3[Fe(CN)6]/K4[Fe(CN)6] solution, suggesting its potential application in electrochemical analysis. [Copyright &y& Elsevier]

Abstract: Copper sulfide nanocrystals (CuS NCs) with different morphologies were synthesized via solvothermal method using copper acetate and sulfur chloride as precursors. Hereinto, CuS NCs with geometrical symmetry was prepared in 95% ethanol. The crystal structures were characterized by X-ray diffraction, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), electron diffraction (SAED), UV–vis and Fourier transform infrared spectroscopy (FT-IR). The typical nanostructure was constructed of eight intersectant nanoflakes with half hexagon shape. The influences of solvent, sulfur sources, water/ethanol volume ratio and reaction temperature on the morphology of products were investigated. Moreover, the possible formation process about geometrical symmetry-like CuS nanocrystals was proposed based on the time-dependent experiments. The electrode modified by CuS NCs of different morphologies showed excellent electrocatalytic activities to Methyl Orange (MO). The good analytical performance makes CuS NCs/chitosan/GC modified electrode (CuS NCs/CS/GCE) as promising electrochemical sensor for Methyl Orange. [Copyright &y& Elsevier]

Abstract: Nano BiFeO3 (BFO) with three different morphologies was successfully synthesized by different synthesis routes. Platelet-like BFO with antiferromagnetic behavior was synthesized by hydrothermal (HT) method. BFO nanoparticles and irregularly shaped BFO aggregation were synthesized by microwave-assisted sol–gel (MSG) method within citric acid (CA) and ammonia aqueous (NH3·H2O) solution, respectively. Both exhibited weak magnetism. Meanwhile, irregularly shaped BFO aggregation revealed relatively narrow band gap energy. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were applied to investigate the electrochemistry performance of BFO-chitosan-glassy carbon (BFO-CS-GCE) modified electrode. It was found that BFO nanoparticles possessed the highest electrocatalytic activity and potential application for electrochemical analysis. [Copyright &y& Elsevier]

Tellurium (Te), as an elementary material, has attracted intense attention due to its potentially novel properties. However, it is still a great challenge to realize high‐quality 2D Te due to its helical chain structure. Here, ultrathin Te flakes (5 nm) are synthesized via hydrogen‐assisted chemical vapor deposition method. The density functional theory calculations and experiments confirm the growth mechanism, which can be ascribed to the formation of volatile intermediates increasing vapor pressure of the source and promoting the reaction. Impressively, the Te flake‐based transistor shows high on/off ratio ≈104, ultralow off‐state current ≈8 × 10−13 A, as well as a negligible hysteresis due to reducing thermally activated defects at 80 K. Moreover, Te‐flake‐based phototransistor demonstrates giant gate‐dependent photoresponse: when gate voltage varies from −70 to 70 V, Ion/Ioff is increased by ≈40‐fold. The hydrogen‐assisted strategy may provide a new approach for synthesizing other high quality 2D elementary materials. [ABSTRACT FROM AUTHOR]

Near infrared (NIR) photodetectors based on 2D materials are widely studied for their potential application in next generation sensing, thermal imaging, and optical communication. Construction of van der Waals (vdWs) heterostructure provides a tremendous degree of freedom to combine and extend the features of 2D materials, opening up new functionalities on photonic and optoelectronic devices. Herein, a type‐II InSe/PdSe2 vdWs heterostructure with strong interlayer transition for NIR photodetection is demonstrated. Strong interlayer transition between InSe and PdSe2 is predicted via density functional theory calculation and confirmed by photoluminance spectroscopy and Kelvin probe force microscopy. The heterostructure exhibits highly sensitive photodetection in NIR region up to 1650 nm. The photoresponsivity, detectivity, and external quantum efficiency at this wavelength respectively reaches up to 58.8 A W−1, 1 × 1010 Jones, and 4660%. The results suggest that the construction of vdWs heterostructure with strong interlayer transition is a promising strategy for infrared photodetection, and this work paves the way to developing high‐performance optoelectronic devices based on 2D vdWs heterostructures. [ABSTRACT FROM AUTHOR]

[Display omitted] Tricobalt tetroxide (Co 3 O 4) has been developed as a promising photocatalyst material for various applications. Several reports have been published on the self-modification of Co 3 O 4 to achieve optimal photocatalytic performance. The pristine Co 3 O 4 alone is inadequate for photocatalysis due to the rapid recombination process of photogenerated (PG) charge carriers. The modification of Co 3 O 4 can be extended through the introduction of doping elements, incorporation of supporting materials, surface functionalization, metal loading, and combination with other photocatalysts. The addition of doping elements and support materials may enhance the photocatalysis process, although these modifications have a slight effect on decreasing the recombination process of PG charge carriers. On the other hand, combining Co 3 O 4 with other semiconductors results in a different PG charge carrier mechanism, leading to a decrease in the recombination process and an increase in photocatalytic activity. Therefore, this work discusses recent modifications of Co 3 O 4 and their effects on its photocatalytic performance. Additionally, the modification effects, such as enhanced surface area, generation of oxygen vacancies, tuning the band gap, and formation of heterojunctions, are reviewed to demonstrate the feasibility of separating PG charge carriers. Finally, the formation and mechanism of these modification effects are also reviewed based on theoretical and experimental approaches to validate their formation and the transfer process of charge carriers. [ABSTRACT FROM AUTHOR]

Although tremendous attempts have been made to transform vegetable oils into value-added chemicals, most of the known protocols still require cumbersome preparation procedures for the raw materials, high temperatures, and long reaction times, accompanied with encumbering economic costs and low energy efficiency. In this manuscript, a simple, scalable, and ultrafast method for the synthesis of fully bio-based internal emulsifiers is reported. Flow chemistry was applied to achieve a photo-click, thiol–ene reaction at room temperature by using a cysteine derivative and castor oil as natural raw materials. Conversion rates up to 92.0% were obtained, and the productivity of the internal emulsifier NACCO could reach 360.0 g h−1 with a custom flow chemistry setup. The fully bio-based internal emulsifier was further applied to synthesize waterborne polyurethanes with typical polyols. The bio-content of these waterborne polyurethanes could be as high as 90.0 wt%. Moreover, the films derived from waterborne polyurethanes exhibit superior thermophysical and mechanical properties to known solvent- and petroleum-based polyurethane films. The novel emulsifier, prepared via photo-click thiol–ene chemistry, bridges natural materials (amino acid derivatives and castor oil) and fossil-based products; this affords a green and sustainable strategy for the synthesis of waterborne polyurethanes, which will decrease our chemical dependence on fossil resources. [ABSTRACT FROM AUTHOR]

An ultrathin and uniform Sm 2 O 3 rare earth oxide functional coating is formed to enhance the lithium storage performance of high-voltage medium-nickel low-cobalt LiNi 0.6 Co 0.05 Mn 0.35 O 2 cathode. The multi-electron rare earth oxide functional coating improves electrode–electrolyte interfacial stability and bulk structural stability by acting as a physical passivation layer and charge compensation payer. [Display omitted] • An ultrathin and uniform Sm 2 O 3 rare earth oxide functional coating is obtained. • Sm 2 O 3 coating acts as a physical passivation layer and charge compensation payer. • Multi-electron Sm 2 O 3 coating enhances the interfacial lattice oxygen stability. • The interfacial, thermal, and bulk structural stability are improved. • An excellent high-voltage medium-nickel low-cobalt LiNi 0.6 Co 0.05 Mn 0.35 O 2 cathode. High-voltage medium-nickel low-cobalt lithium layered oxide materials have been recognized as a kind of promising cathodes to further promote the energy density of lithium-ion batteries (LIBs) due to their relatively high capacity, low cost, and improved safety. However, the high voltage induced bulk structure degradation and interfacial environment deterioration limit the performance liberation of this kind of cathodes. Here, an ultrathin and uniform Sm 2 O 3 rare earth oxide functional coating has been introduced to enhance the lithium storage performance of LiNi 0.6 Co 0.05 Mn 0.35 O 2 (NCM) cathode. On the one hand, this multi-electron Sm 2 O 3 function coating could increase the activation energy of surface lattice oxygen loss, improving the electrode–electrolyte interface stability; on the other hand, it delays the phase transition temperature and weakens the harmful H3 phase transition of NCM, improving its thermal stability as well as minimizing the mechanical degradation. These beneficial effects endowed by the Sm 2 O 3 coating imply that it could behave as both a physical passivation layer and a charge compensation payer. As a result, the 2%-Sm 2 O 3 @NCM delivers a higher capacity retention rate (97.3% vs 75.0% after 150 cycles) and a superior rate capacity (117 mAh g−1 vs 52 mAh g−1 at 5C) than the pristine NCM, making high-voltage lithium layered oxide one step closer to being a viable cathode. [ABSTRACT FROM AUTHOR]

2D carbides and nitrides of transition metals, also known as MXenes, are an emerging class of 2D nanomaterials that have shown excellent performances and broad application prospects in the fields of energy storage, catalysis, sensing, electromagnetic shielding, electronics and photonics, and life sciences. This unusual diversity of applications is due to their superior hydrophilicity and conductivity, high carrier concentration, ultra-high volumetric capacitance, rich surface chemistry, and large specific surface area. However, it is difficult to make MXenes with the desired surface functional groups that deliver high reactivity and high stability, because most MXenes are extracted from ceramics (MAX phase) by an etching process, where a large number of metal atoms are inevitably exposed on the surface, with other anions and cations embedded uncontrollably. The exposed metal atoms and implanted ions are thermodynamically unstable and readily react with trace oxygen or oxygen-containing groups to form the corresponding metal oxides or degrade chemically, resulting in a sharp decline in activity and loss of excellent physicochemical properties. The addition of certain synergistic additives during the intercalation and chemical modification of surface functional groups under non-hazardous conditions can result in stable and efficient MXene-based materials with exceptional optical, electrical, and magnetic properties. This review discusses several such methods, mainly additive-mediated intercalation and chemical modification of the surface functional groups of MXene-based materials, followed by their potential applications. Finally, perspectives are given to discuss the future challenges and promising opportunities of this exciting field. [ABSTRACT FROM AUTHOR]

Highlights: [•] A SERS substrate was synthesized by fixing Ag onto Fe3O4 magnetic particles. [•] The analysis of Raman insensitive GSH was achieved with Raman sensitive crystal violet as a probe. [•] The new method can determine GSH in the range of 50–700nmolL−1 with a detection limit of 40nmolL−1. [•] The proposed method has good selectivity and reproducibility for trace GSH detection in real samples. [ABSTRACT FROM AUTHOR]

To date, the piezoelectric field has been demonstrated as a promising approach to inhibit the recombination of photogenerated carrier in photocatalyst applications. Herein we propose a MoS 2 /Bi 4 O 5 Br 2 /PVDF-HFP piezo-photocatalytic film in the organic pollutants remediation. MoS 2 /Bi 4 O 5 Br 2 as the photocatalytic material is incorporated to poly (vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP) as the supporting layer via a simple phase transition method. The polarised electric field generated on PVDF-HFP and MoS 2 /Bi 4 O 5 Br 2 under aeration synergised with the built-in electric field formed between MoS 2 /Bi 4 O 5 Br 2 Z-scheme heterojunction to promote the interfacial charge transfer. The degradation rates of rhodamine B (RhB) and tetracycline hydrochloride (TC) under aeration and visible light irradiation in 60 min reached 98.9% and 92.2%, respectively. Meanwhile, density functional theory calculations (DFT) further demonstrated the effective charge separation and transfer induced by the Z-scheme charge transfer mechanism constructed by MoS 2 composite with Bi 4 O 5 Br 2 , as well as the synergistic effect of the double electric field in favour of suppressing carrier recombination. This work provides an interesting solution for effectively combining piezoelectric catalysis with photocatalysis. [Display omitted] • MoS 2 /Bi 4 O 5 Br 2 forms a Z-scheme heterojunction that retains a high redox capacity. • Piezoelectric field and built-in electric field synergistically enhance photocatalytic performance. • Utilizing aeration as the driving force to generate the piezoelectric effect is simple and energy efficient. • DFT calculations confirm the double electric field effect of the photocatalytic system. [ABSTRACT FROM AUTHOR]

AIE fluorophores have been developed as bioimaging probes due to their strong brightness at high concentration and increase of the photostability to promote highly recognizable cellular signaling. However, conventional AIE fluorescent probes for bioimaging just solely lighten the cells or tissues, suffering from the limitation of satisfying the requirement of disease diagnosis. Herein, we report an AIE-active bioprobe (TPP-Tba) for linear fluorescence response and qualitative detection of hydrogen peroxide (H2O2) and viscosity with a wide detection range and a low detection limit. TPP-Tba displays an impressive ability of distinguishing normal cells and pathological cells. Furthermore, fatty liver tissue can also be efficiently distinguished from normal liver tissue, attributed to the great H2O2 and viscosity dual-response as well as the specific targeting to mitochondria by TPP-Tba. Given the high sensitivity for H2O2 and viscosity, great biocompatibility, high specificity to mitochondria, and impressive ability of distinguishing normal tissue and pathological tissue, we envisage that this novel TPP-Tba probe would open a new window for designing novel bioprobes for disease diagnosis. [ABSTRACT FROM AUTHOR]

• Hollow materials are constructed by Kirkendall effect, GRR, and Ostwald ripening. • The fabrication of core-shell materials with tailored compositions is presented. • Three synthesis methods of LDHs are proposed. • Five strategies for improving the sensing performance are summarized. In this review, we present an overview of different methods for preparing Cu-based materials with a focus on the preparation of hollow structural materials using Kirkendall effect, Galvanic replacement reaction (GRR), and Ostwald ripening principles. We also discuss the design of complex hollow and core–shell structures using ion exchange, co-etching precipitation, sulfidation, self-template, one-pot, GRR, and ligand protection methods. Additionally, we review recent research on Cu-based LDHs and propose three synthetic strategies: hydrothermal, one-step coprecipitation, and electrodeposition. To enhance the electrochemical sensing performance of Cu-based materials, we suggest five strategies, such as maximizing specific surface area, constructing a heterogeneous structure, optimizing electronic configuration, decorating 3D porous binder-free electrodes, defect engineering. Furthermore, we highlight the advanced applications of Cu-based materials in human health management, such as glucose sensing, H 2 O 2 sensing, uric acid sensing, and dopamine sensing. Finally, we summarize the challenges encountered in the preparation of Cu-based materials and the application of biosensors and provide prospects for the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Au-θ-Al 2 O 3 /Au/PCN is prepared by co-design of active site and assembled structure. • The multiple internal electric fields are induced by electron diffusion effect. • The LSPR effect contributes to photocatalytic CO 2 R reaction. • Atomically dispersed Au atoms confined by oxygen vacancies provide active sites. • The photocatalytic CO 2 R performance is propelled dramatically. A new Au-θ-Al 2 O 3 /Au/PCN hybrid is fabricated by the collaborative design strategy of active site and assembled structure, which achieves highly efficient photocatalytic CO 2 reduction (CO 2 R) performance. The energy band structure of PCN is adjusted significantly owing to the strong coupling effect of Au-θ-Al 2 O 3 /Au nanosheets intercalated in PCN nanosheets. The result brings about up-shift of CB, VB and Fermi energy level overall and decrease of bandgap, which is in favor of harvesting visible light, exciting VB electrons and increasing reduction ability. In addition, the multiple built-in electric fields are induced by electron diffusion effect between structural units, due to the tight interface contact in the Au-θ-Al 2 O 3 /Au/PCN hybrid, which can effectively promote the separation of photoinduced charge carriers. Furthermore, the atomically dispersed Au atoms confined by the oxygen vacancies in Au-θ-Al 2 O 3 /Au can provide the plenty of effective active sites for CO 2 R reaction, and meanwhile, the localized surface plasmon resonance (LSPR) effect induced by Au nanoparticles on Au-θ-Al 2 O 3 /Au can improve the visible light response and produce abundant hot electrons to contribute to CO 2 R reaction. As a consequence, the average CO evolution rate of over the optimizing 10 %-Au-θ-Al 2 O 3 /Au/PCN hybrid (7.76 μmol g-1h−1) reaches up to 3.53 times than that of PCN (2.20 μmol g-1h−1) in the CO 2 R reaction, and maintains basically stable operation within 7 cycles of running, suggesting the superior activity and recyclability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ru(III)/TiO 2 can activate periodate for rapid oxidation of organic pollutants. • Homogeneous Ru(V) = O species were identified as the dominant oxidant. • Ru(III) catalysts can be recycled via reaction of Ru(V) = O with organic pollutants. • Ru(III)/TiO 2 - periodate was highly selective in degradation of organics. • Ru(III)/TiO 2 - periodate exhibited high anti-inference to complex water matrixes. Recently, metal catalysts have received much attention in periodate (PI) activation for production of reactive oxygen species to efficiently degrade organic contaminants, yet activation efficiency is cumbered with their sluggish catalytic cycle. In the study, TiO 2 supported Ru(III) catalysts (Ru(III)/TiO 2 , 0.45 wt% as Ru) were used to catalyze PI activation for oxidation of aqueous organic pollutants. Ru(III)/TiO 2 exhibited comparable performance with homogeneous Ru(III) for phenol degradation via PI activation at initial pH = 4, 7 and 10. Moreover, the Ru(III)/TiO 2 -PI system showed high selectivity for degradation of electron-rich organic contaminants. In comparison, benzoic acid and ibuprofen were hardly oxidized in the system. Scavenging tests, H 2 18O-isotope labeled methyl phenyl sulfoxide (PMSO) probe experiments, X-ray absorption near-edge structure spectra and Electron Spin Resonance analysis confirm formation of Ru(V) = O species as dominant oxidant in the process with little involvement of IO 3 , OH and O 2 −. The formed Ru(V) = O species were further confirmed to be water-soluble via analysis of Ru distribution between aqueous solution and TiO 2 surface. They can be reduced to Ru(III) species by reacting with organics, realizing the catalytic cycle of Ru(III) → Ru(V) = O → Ru(III) and self-recycle of Ru(III) onto TiO 2 surface. In addition, PI was decomposed in stoichiometry into IO 3 – without generation of undesired iodine species (i.e., HOI and I 2). This study advances understandings of PI activation mechanism by heterogeneous Ru(III) catalysts, and also provides a promising oxidation technology for wastewater purification. [ABSTRACT FROM AUTHOR]

Taking the advantage of the good matching of the valence and conduction bands of carbon nitride (g-C 3 N 4) and copper oxide (CuO), we successfully fabricated a two-dimensional (2D) step-scheme heterojunction of g-C 3 N 4 /CuO via hydrothermal and pyrolysis techniques. The potential of applying this heterojunction in a high-performance electrochemical sensor for environmental hormone nonylphenol (NP) detection was investigated. An amperometric analysis resulted in a linear response on the g-C 3 N 4 /CuO modified sensor for NP ranges from 3.00 × 10−8 to 5.12 × 10−6 mol L−1 with a detection limit (S/N = 3) of 1.20 × 10−8 mol L−1. This excellent electrochemical performance could be attributed to a built-in electric field effect at the 2D step-scheme heterojunction interface, thereby boosting the interfacial charge transfer and improving the sensitivity of NP detection. The proposed sensor demonstrated a high selectivity for NP even in the presence of several common environmental hormones. This finding can be attributed to the unique electronic structure of NP molecule and its strong interaction with the 2D g-C 3 N 4 /CuO step-scheme heterojunction, as verified by density functional theory (DFT) calculations. This work provides new insights about the gradient energy band for fabricating highly-efficient electrochemical sensor, and paves the way for its potential applications in monitoring crucial environmental components. [ABSTRACT FROM AUTHOR]

• The heteroatom X (X = N, B, P, S) doping effect on the HER of M 2 C-MXenes (M = Ti, Mo) were systemtically studied. • The X doped M 2 CT 2 (M = Mo, Ti; T = O) exhibits remarkable electrocatalytic performance for HER. • The heteroatom doping improves the electrical conductivity of Ti 2 CO 2. • The N-doped Ti 2 CO 2 -MXene has improved electrocatalytic activity than the Pt (1 1 1). Half-reaction of water splitting is hydrogen evolution reaction (HER), which requires low cost and high activity catalysts. Two-dimensional (2D) transition metal carbon/nitrides (MXene) materials have shown great potential as highly efficient catalysts due to their excellent properties. In this work, the heteroatom X (X = N, B, P, S) doping effect on the HER of M 2 C MXene (M = Ti, Mo) with or without oxygen functional groups have been performed by well-defined density functional calculations (DFT). The X doped M 2 CT 2 (M = Mo, Ti; T = O) exhibited better HER catalytic activity than the X doped pristine M 2 C (M = Mo and Ti). Moreover, the calculated Gibbs free energies of hydrogen adsorption (ΔG H) indicate that the N-doped Ti 2 CO 2 has improved electrocatalytic activity than that of Pt(1 1 1). Additionally, based on the electronic structure of X-doped Ti 2 CO 2 , the electrical conductivity of N-doped Ti 2 CO 2 is higher than that of pristine Ti 2 CO 2. [ABSTRACT FROM AUTHOR]

Efficient catalyst with enhanced activity and high stability is important for chemical industry. Active species, support as well as their interaction play key roles on catalytic performance for supported heterogeneous catalysts. In this work, Pd Fe dual-metal nanoparticles (NPs) were anchored and confined in an interface of double-layered carbon nanotubes/nitrogen-doped carbon (CNT/NC) support to obtain a dual-metal CNT/PdFe/NC catalyst. The microstructure and composition of CNT/PdFe/NC catalyst were systematically characterized by transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD) and surface area analysis. Benefiting from the catalytically active tubular CNT/NC support, uniformly dispersed Pd Fe dual-metal NPs and unique confined structure, the CNT/PdFe/NC catalyst exhibited excellent catalytic activity for nitroarenes reduction reaction. The catalytic activity of the Pd Fe dual-metal NPs was much better than that of monometal counterparts (CNT/Pd/NC and CNT/Fe/NC), showing an enhanced synergetic effect. The catalytic turnover frequency (TOF) of the CNT/PdFe/NC catalyst amounted to 70.36 min−1 toward 4-nitrophenol (4-NP) reduction reaction, being superior to previously reported noblemetal-based catalysts. Furthermore, this catalyst also exhibited an excellent stability and reusability due to the intrinsic confined structure. This work provides valuable insights to rationally design and develop an efficient dual-metal catalyst. Unlabelled Image • An efficient Pd Fe dual-metal catalyst is developed via a facile encapsulating method. • The prepared dual-metal catalyst exhibits excellent activity for nitroarene reduction. • A confined structure is constructed to enhance the stability of catalyst. • The synergetic effect of support and Pd Fe dual-metal nanoparticles is investigated. [ABSTRACT FROM AUTHOR]

• A biochar cathode was fabricated via pyrolysis of recovered wood-waste. • Sulfathiazole (STZ) was degraded for the first time by electro-Fenton (EF). • Pyrophosphate (PP) was used as a novel alternative to conventional electrolytes. • H 2 O 2 was more stable in PP electrolyte than that of Na 2 SO 4. • STZ degradation pathway by EF was proposed. For the first time, a biomass-derived porous carbon cathode (WDC) was fabricated via a facile one-step pyrolysis of recovered wood-waste without any post-treatment. The WDC along with pyrophosphate (PP) as electrolyte were used in electro-Fenton (EF) at pH 8 for sulfathiazole (STZ) treatment. The H 2 O 2 accumulation capacity of WDC was optimized via the following parameters: pyrolysis temperature, applied current and electrolyte. Results showed that the WDC cathode prepared at 900 °C achieved the highest H 2 O 2 accumulation (13.80 mg L−1 in 3 h) due to its larger electroactive surface area (28.81 cm2). Interestingly, it was found that PP decreased the decomposition rate of H 2 O 2 in solution as compared to conventional electrolyte, which resulted in higher H 2 O 2 accumulation. PP allowed operating EF at pH of 8 due to the formation of Fe2+-PP complexes in solution. Moreover, Fe2+-PP was able to activate oxygen to produce OH. In this way, the degradation of STZ took place through four main pathways: 1) via OH from the Fe2+-PP complex, 2) via OH from EF reactions, 3) via surface OH at the boron doped diamond electrode (BDD) and 4) via SO 4 - from BDD activation. Finally, microtox tests revealed that some toxic intermediates were generated during WDC/BDD/PP EF treatment, but they were removed at the end of the process. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) exhibited huge application potential in electrochemical analysis field, how to facilely and effectively boost the electrochemical sensing activity of MOFs materials still face enormous challenges. In this work, core-shell Co-MOF (Co-TCA@ZIF-67) polyhedrons with hierarchical porosity was easily synthesized via simple chemical etching reaction by selecting thiocyanuric acid as the etching reagent. Benefiting from the introduction of mesopores and thiocyanuric acid/Co2+ complex on the surface of ZIF-67 frameworks, the property and functions of the pristine ZIF-67 was seriously tailored. Compared with the pristine ZIF-67, the as-resulted Co-TCA@ZIF-67 nanoparticles displayed greatly enhanced physical adsorption capacity and electrochemical reduction activity toward the antibiotic drug furaltadone. As a result, a novel furaltadone electrochemical sensor with high sensitivity was fabricated. The linear detection range was from 50 nM to 5 μM with sensitivity of 110.40 μA−1 μM−1 cm−2 and detection limit of 12 nM. This work demonstrated chemical etching strategy is truly a facile and effective way to modify the electrochemical sensing performance of MOFs-based materials, and we believed the chemically etched MOFs materials will play a stronger role in terms of food safety and environmental conservation. [Display omitted] • Co-MOF with unique core-shell structure and hierarchical porosity was easily prepared. • Core-shell Co-MOF exhibited remarkably enhanced physical adsorption ability. • Robust electrochemical sensing platform with high sensitivity and selectivity. • Simple strategy for guiding the synthesis of other MOFs-based sensing materials. [ABSTRACT FROM AUTHOR]

Highlights • Ultrathin (UT) g-C 3 N 4 with an average thickness of 2 nm was prepared by thermolysis. • The UT-g-C 3 N 4 /Ag hybrids were fabricated via a photo-assisted reduction method. • UT-g-C 3 N 4 /Ag/GCE exhibited good electrochemical activity for sensing of l -tyrosine. • A reliable sensing technique was proposed in commercialized l -tyrosine tablets. Abstract Ultrathin (UT) g-C 3 N 4 with a thickness of ∼2 nm was prepared via a facile thermal exfoliation method using bulk g-C 3 N 4 as precursor. The UT-g-C 3 N 4 sample obtained exhibited a large specific surface area of 192.9 m2·g−1. The UT-g-C 3 N 4 /Ag hybrids were fabricated by a photo-assisted reduction technique. The morphology, microstructure and composition of the UT-g-C 3 N 4 /Ag hybrids were systematically characterized by transmission electron microscopy (TEM), aberration-corrected scanning transmission electron microscopy (STEM), STEM-energy dispersive X-ray (EDX) spectrometry, atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS). Based on electrochemical impedance spectroscopy (EIS) results, the optimal UT-g-C 3 N 4 /Ag hybrids displayed a faster electron transfer rate in comparison of UT-g-C 3 N 4 and bulk g-C 3 N 4. Moreover, in the presence of a phosphate buffer solution (pH = 6.0), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) results showed that the UT-g-C 3 N 4 /Ag hybrids coated on glassy carbon electrode (denoted as UT-g-C 3 N 4 /Ag/GCE) exhibited excellent electrochemical properties for l -tyrosine detection. It is observed that the electrochemical response of was linear in the concentration range of 1.00 × 10−6 to 1.50 × 10−4 mol L−1 with a limit of detection (S/N = 3) of 1.40 × 10−7 mol L−1, superior to the other reported sensors. The developed UT-g-C 3 N 4 /Ag/GCE sensor was employed for l -tyrosine detection in commercial l -tyrosine tablet samples, and the recovery of 97.2–99.3% was observed. This proposed g-C 3 N 4 -based electrochemical sensor provides a rapid and sensitive sensing method for l -tyrosine detection in real samples. [ABSTRACT FROM AUTHOR]

In this paper, a novel, fully bio-based emulsifier has been successfully prepared from epoxidized soybean oil and glutaric acid through a solvent-free and self-catalysis method. The effects of reaction time and carboxyl : epoxy molar ratios on the structures of the emulsifier were systematically investigated. This novel emulsifier exhibits properties similar to those of dimethylolpropionic acid (DMPA) and dimethylolbutanoic acid (DMBA), with hydroxyl groups serving as crosslinking agents and the carboxylic acid group acting as an ionic segment. In order to validate the robustness of this emulsifier, a series of anionic, waterborne polyurethane dispersions were prepared from typical polyols (vegetable oil- and petroleum-based). The structure of this emulsifier and its good compatibility with bio-based polyols confer the resulting dispersions excellent storage stability and high solid content (up to 45%). The prepared waterborne polyurethane films exhibited higher toughness and thermal stability than traditional solvent-based polyurethane films and waterborne polyurethane films prepared from DMPA and DMBA. Moreover, a high bio-based content of up to 74% was achieved for the prepared polyurethanes. This new environmentally friendly, liquid emulsifier, prepared using a solvent-free and self-catalysis synthetic route, can potentially replace typical petroleum-based emulsifiers for the production of waterborne polyurethanes. [ABSTRACT FROM AUTHOR]

Ternary heterojunctions g-C3N4/ZnS/CuS with different morphologies were constructed. The g-C3N4/ZnS/CuS (hexagonal-nanosheets) exhibited the largest photocurrent, the best photocatalytic and electrochemical activity, which revealed the influence discipline of different morphologies on photoconductivity, photo/electro-catalytic activity. It indicated that this heterojunction can be used as an excellent photoconductor device, a high-efficiency photo/electro-catalyst.Graphical Abstract: [ABSTRACT FROM AUTHOR]

A facile sensor based on two-dimensional (2D) g-C 3 N 4 /CuO nanocomposites was proposed for electrochemical detection of dopamine (DA). The 2D g-C 3 N 4 /CuO nanocomposites were fabricated by a pyrolysis technique using melamine and cupric acetate monohydrate as precursors. The 2D g-C 3 N 4 /CuO nanocomposites prepared have a larger conductivity and a narrower band-gap than that of pure g-C 3 N 4 , resulting in higher electrochemical activity for sensing of DA. The response of this sensor is linear over the range of 2.00 × 10 −9 to 7.11 × 10 −5  mol L −1 with a detection limit of 1.00 × 10 −10  mol L −1 . The ultra-high sensitivity can be attributed to an electron transfer process on the surface of the sensor, where the 2D g-C 3 N 4 /CuO is a powerful electron donor and the oxidized DA quinone functions as an efficient electron acceptor, as confirmed by density functional theory (DFT) calculations. The sensor showed a high selectivity to DA over common interfering biological small molecules (including glucose, uric acid and ascorbic acid), as the DA quinone possesses the most positive electrostatic potential and the smallest electron-injection-barrier between the 2D g-C 3 N 4 /CuO and DA quinone, which was also supported by DFT calculations. The proposed novel sensor provides a facile yet ultra-sensitive electrochemical sensing method for detecting trace DA in real biological samples. [ABSTRACT FROM AUTHOR]

The construction of high-quality graphitic carbon nitride (g-C 3 N 4 )-based heterojunctions remains a grand challenge. Herein, the ternary heterojunctions of g-C 3 N 4 /ZnS/CuS has been fabricated via a facile three-step process: the polymerization of melamine, the loading of ZnS nanoparticles (NPs), and further deposition of hexagonal CuS nanosheets. Compared with pure g-C 3 N 4 , there is an extended visible-light absorption over 500–800 nm for g-C 3 N 4 /ZnS/CuS, which enables the possible utilization of low-energy visible light. Moreover, ZnS NPs interface layers and hexagonal CuS nano-sheets can be both utilized as electron co-catalysts to markedly improve the separation efficiency of the photo-generated electrons and holes and decrease interface transfer resistance, resulting in highly efficient photocatalytic activity for degradation of Rhodamine B (RhB) and significantly enhanced photoconductivity in an all-solid-state device. This work can be helpful for developing other effective hetero-structured photocatalysts and photoelectrical devices. [ABSTRACT FROM AUTHOR]

The rational fabrication of an efficient photocatalyst with optimal interface engineering remains a huge challenge for the enhancement of photocatalytic perpformance. Herein, a sequence of multidimensional nanocomposites with different spatial interfaces, including point, and line or face-contact surface are controllable designed by horizontal growing diverse dimensional (0D, 1D,2D and 3D) copper sulfide (CuS) on 2D graphitic-carbon nitride (g-C 3 N 4) nanosheets. Physical and photochemical measurements demonstrate that the formation of an extraordinary 2D/2D face-to-face contact interface can not only enhance the specific surface area, visible light utilization, and photo-excited charge separation efficiency, but also elevate the density and lifetime of photo-generated carriers. The results of ultraviolet photoemission spectroscopy (UPS) and density functional theory (DFT) calculation also confirm that charge transfer tends to occur in face-to-face contact. Among the types of nanocomposites considered, 2D/2D g-C 3 N 4 /CuS has the smallest electron transfer barrier (Ф Be) between active species, thereby displaying the maximum photocatalytic apparent rate constant, which is about 12 times larger than that of pristine g-C 3 N 4. Most importantly, this work systematically investigates the relationship between microscopic interface structure and photocatalytic activity from the perspective of the optical, and electrical and energy levels, providing a new insight on the rational design of desired interface engineering towards efficient photocatalysts. [Display omitted] • 2D/xD g-C3N4/CuS nanocomposites with different spatial interfaces were fabricated. • 2D/2D g-C3N4/CuS nanocomposite displays the optimal photocatalytic performance. • The concentration, lifetime and separation-efficiency of photogenerated carriers were tested. • The energy barrier between active species and catalysts was analyzed by UPS and DFT. • The photocatalytic mechanism of 2D/2D g-C3N4/CuS nanocomposites is proposed. [ABSTRACT FROM AUTHOR]

Nickel oxide and nickel co-doped graphitic carbon nitride (NiONiGCN) nanocomposites were successfully prepared by thermal treatment of melamine and NiCl2 ⋅ 6H2O. NiONiGCN nanocomposites showed superior electrochemical catalytic activity for the oxidation of octylphenol to pure GCN. A detection method of octylphenol in environmental water samples was developed based at NiONiGCN nanocomposites modified electrode under infrared light irradiation. Differential pulse voltammetry was used as the analytic technique of octylphenol, exhibiting stable and specific concentration-dependent oxidation signal in the presence of octylphenol in the range of 10 nM to 1 µM and 1 µM to 50 µM, with a detection limit of 3.3 nM (3S/N). [ABSTRACT FROM AUTHOR]

Correction for 'Additive-mediated intercalation and surface modification of MXenes' by Jing Zou et al., Chem. Soc. Rev., 2022, DOI: 10.1039/d0cs01487g. [ABSTRACT FROM AUTHOR]

[Display omitted] • HA changed photo-degradation pathways of bromophenols. • HA depressed hydrolysis of organic radicals. • HA activation induced formation of OH, NO 2 and NH 2. • HA triggered formation of nitro byproducts from photolysis of bromophenols. Photolysis of bromophenols and nitrogen cycle are two common processes in the natural water bodies. In the study, effect of hydroxylamine (HA), an intermediate of nitrogen cycle, on UV photolysis of bromophenols in the aqueous solution was investigated under different conditions. It was found that HA presence not only changed formation of reactive species, also varied degradation pathways of 2,4,6-tribromophenol (TBP). During photolysis of TBP, carbon-centered radicals (C), H and e aq − were produced, while new radicals of OH, NO 2 and NH 2 were produced after addition of HA. Moreover, the added HA greatly inhibited hydrolysis of C via the reaction between them, thereby depressing formation of hydroxylated intermediates (e.g., monohydroxylated 2,6-dibromophenol), and improving debromination of TBP in UV/HA/TBP system. It is worth noting that two new nitro/amino byproducts of concern were detected in UV/HA/TBP system. They are proposed to be generated from the combination of C with NO 2 and NH 2. Furthermore, nitro/amino byproducts were one of the major sink pathways of HA in UV/HA/TBP system. This is the first article to demonstrate the formation of nitro/amino byproducts form photodegradation of phenolic compounds in the presence of HA, and to clarify reaction mechanism for generation of OH, NO 2 and NH 2 from HA activation during photolysis of bromophenols in the aqueous solution. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reactive species in Cu-catalyzed persulfate activation are summarized. • Cu-catalyzed radical/nonradical persulfate activation pathways are elaborated. • Uncertainties on role of Cu-catalysts in persulfate activation are explicated. • Controversies over persulfate activation mechanism are discussed. Persulfate-based Advanced oxidation processes (AOPs) have gained a lot of attentions in organic decontamination in the past decades. Copper (Cu)/persulfate is an interesting coupling system due to its versatile activation pathways with formation of multiple radical and nonradical species. Thus, in the review, the generation mechanisms of various reactive species in Cu/persulfate system are analyzed and summarized. Firstly, the general activation mechanisms of Peroxydisulfate (PDS) and Peroxymonosulfate (PMS) catalyzed by Cu are summarized, and formation processes of four types of free radicals (SO 4 −, OH, SO 5 − and O 2 −) and three types of non-radicals (Cu(III), surface activated PDS/PMS and 1O 2) in the system are compared. Moreover, the role of copper ions and copper oxides in generation of these reactive species is discussed in details. Finally, the concluding remarks and perspectives for future research on Cu/persulfate AOPs are proposed. The review provides a comprehensive and deep insight into the formation and reaction mechanisms of radical and nonradical species, points out current controversies over reaction mechanisms involved in the Cu-persulfate-based AOPs, and proposes a guideline for future research and engineering application of persulfate. [ABSTRACT FROM AUTHOR]

[Display omitted] • UV irradiation can degrade and debrominate bromophenols. • Hydrogen radicals (H•) and e aq − were generated from photolysis of bromophenols. • Contribution rate of e aq − in TBP degradation was 35.8%-40% at pH 0 4–11. • Photo-degradation pathways of 2,4,6-tribromophenol were proposed. • Effect of water matrices and photolysis of TBP in actual water were checked. Photolysis and debromination of bromophenols were widely investigated previously. However, the role of reactive species especially hydrated electrons (e aq −) in their degradation was overlooked. Therefore, in the study, generation and role of the reactive species generated during the photolysis of bromophenols were identified and evaluated by using 2,4,6-tribromophenol (TBP) as a model at different pH values from 4 to 11 under anaerobic condition. It was found that photolysis of TBP solution under UV irradiation (254 nm) yielded organic radicals (C•), hydrogen radicals (H•) and e aq −. By using nitrite and monochloroacetic acid (MCAA) as scavengers of H•/e aq −, the role of UV direct photolysis, H• and e aq − in degradation of TBP was quantitatively assessed at different initial pH (pH 0) values. UV irradiation induced direct photolysis of TBP was mainly dependent on its molar absorbance coefficient (ε) at 254 nm. Contribution rate of UV irradiation to degradation of TBP was about 60% at pH 0 4, 7 and 11. Interestingly, the contribution rate of e aq − was high as 35.8%-40% at pH 0 4–11, while the contribution rate of H• was negligible (<2.5%) at these pH values. Accordingly, UV and e aq − induced degradation and debromination pathways of TBP under UV irradiation were proposed. This work gains deep insight into the photolysis process of bromophenols, and clarifies the important role of e aq − in photo-degradation of bromophenols. [ABSTRACT FROM AUTHOR]

A new electrochemical sensor was fabricated by modifying the glass carbon electrode surface with CuS nanocomposites and chitosan for the determination of pentachlorophenol. CuS nanocomposites obtained by a solvothermal method were composed primarily of CuS with hexagonal phase and Cu2Cl(OH)3with a tetragonal phase. The results indicated that CuS nanocomposites possessed good electrochemical activity. After optimizing the experimental conditions, the linear dependence of current vs. pentachlorophenol concentration was reached in a range from 1.88 × 10−6–7.50 × 10−5 mol/L pentachlorophenol, and the detection limit was 6.25 × 10−7 mol/L. The electrode displayed a high degree of stability and reproducibility. A new, simple, rapid, and highly sensitive electrochemical detection method of pentachlorophenol was established. [ABSTRACT FROM AUTHOR]

• The surficial oxygen vacancy on TiO 2 film was innovatively created by CaH 2 treatment. • The activity for benzene photodegredation was improved up to 340% after optimization. • The TiO 2 film exhibits superior stability and can utilize sunlight to degrade benzene. • Band bending occurs between surficial oxygen deficient layer and bulk TiO 2. • The p-n junction model was proposed based on the band bending of DFT results. Engineering the bulk and surface oxygen vacancy defects in titania (TiO 2) photocatalysts has been proved to bean efficient strategy to improve quantum efficiency. In this work, we report a facile and innovative method to manipulate surficial oxygen defects on TiO 2 films using calcium hydride (CaH 2) as a reducing agent. Surficial oxygen defect formation was verified by the combinations of electron paramagnetic resonance (EPR), Raman and UV–Vis absorption spectroscopy. The concentration of surficial oxygen vacancy defects could easily be tuned by varying the temperature and duration of the CaH 2 treatment. After optimization CaH 2 treatment conditions, the activity of TiO 2 films in photodegrading benzene under UV light was enhanced by as much as 340%. The mechanism of surficial oxygen vacancy defect enhancing photocatalytic performances of TiO 2 film was systematically investigated by density functional theory (DFT) calculations, which predict the existence of band bending modelled as a p-n junction between the bulk and the surface layer with oxygen vacancies, thus inhibiting electron-hole recombination, and enabling oxygen transport at different depths for the enhancement of photocatalytic properties. [ABSTRACT FROM AUTHOR]

• S-g-C 3 N 4 nanoflake with a large specific surface area of 189.26 m2 g−1 was prepared. • The proposed S-g-C 3 N 4 /GCE sensor exhibited excellent performance for Pb2+ detection. • The high selectivity can be attributed to a strong interaction via S Pb bond. • The strong interaction between S-g-C 3 N 4 interface and Pb2+ was confirmed by DFT. An optimum large specific surface area of sulfur-doped graphitic carbon nitride nanoflakes modified glassy carbon electrode (S-g-C 3 N 4 /GCE) is reported with promising lead ion (Pb2+) detection capability. This sensor was designed and fabricated using thermal polycondesation reaction. In terms of high selectivity Pb2+ performance, we noted that the sensor exhibited appreciable detection limit of 3.0 × 10−9 mol L−1 (S/N = 3) within the ionic specimen concentration range of 7.5 × 10−8 ~ 2.5 × 10−6 mol L−1 and 2.5 × 10−6 ~ 1 × 10−3 mol L−1. Corroborated by DFT calculations, we propose that the strong interaction of S-g-C 3 N 4 interface and Pb2+ plays an important role to generate the aforementioned sensing characteristics. In practice, we conceived high detection of Pb2+ ions that reside in lake-water and mineral samples in which percentage recovery of 88–103 can be obtained under high repetition rate. Thus, S-g-C 3 N 4 /GCE can be considered as sensitive and selective electrochemical sensor for a reliable detecting heavy metal ions in domestic sewage and industrial wastewater. [ABSTRACT FROM AUTHOR]

Considering their excellent chemical stability and conductivity, transition metal carbide and transition metal nitride coatings are adopted to protect metallic bipolar plates in this study. However, the inevitable adsorption of oxygen on these coatings in the cathodic environment of proton exchange membrane fuel cell (PEMFC) influences their chemical stabilities and conductivities. To asses this influence, first-principle calculations are conducted using CrN, TiC and TiN as examples. We show that in the case of CrN , CrO x ionic bonds are formed on CrN (111), and TiO x formed on TiC (111) and TiN (111) for the case of TiC and TiN, respectively. In addition, the overlapping in the electron density difference distribution of Cr O is more significant than that of Ti O (TiN) and Ti O (TiC). This suggests that CrN has a better chemical stability than TiN or TiC, and therefore, is more suitable for the protective coating of metallic bipolar plates, especially in the cathodic environment of PEMFC. Unlabelled Image • The effect of oxygen adsorption on CrN, TiN and TiC is studied by First principles. • CrO x and TiO x ionic bonds are formed on the surface of CrN, TiN and TiC. • The overlapping in the electron density of Cr O is more significant than Ti O. • CrN is more suitable for the protective coating of bipolar plates than TiN and TiC. [ABSTRACT FROM AUTHOR]

• Porous Ni, N-codoped C networks were prepared through an simple in-situ self-growth NaCl-templated strategy. • The as-synthesized Ni, N-codoped C networks exhibited abundant pores characterization with high specific surface area. • A novel non-enzymatic glucose sensor with excellent performance is developed basing the Ni, N-codoped C networks. • The strategy may provide guidance for the synthesis of other carbon-based materials. Carbon materials have received intensive attention due to their unique property in the field of electrochemical analysis. As transition metallic heteroatom and nitrogen-codoped carbon (M-N-C) materials commonly exhibit enhanced electrochemical activity for the tuned electronic structure, therefore, fabricating a novel structure of M-N-C material for electrochemical analysis is highly pursued. Herein, an in-situ self-growth NaCl-templated strategy is proposed to fabricate three-dimensional porous Ni, N-codoped carbon material (3D Ni-N-C). The as-obtained 3D Ni-N-C demonstrates superior electrochemical performance toward glucose oxidation and sensing, and a highly sensitive and selective non-enzymatic glucose sensor is subsequently developed for human serums with a wide linear range of 0.001–1.20 mM, low detection limit of 0.15 μM, and high sensitivity of 1181.0 μA mM−1 cm-2. It is believed that the unique structural properties of 3D Ni-N-C (abundant N-doped and Ni-N coordinated active sites, large surface area, open micro-porous structure) are conducive to the formation and exposure of highly catalytic centers and improvement of electron-transfer rate. [ABSTRACT FROM AUTHOR]

• A reed-derived biochar modified nickel-foam cathode was elaborated. • Sulfamerazine (SMR) was firstly degraded by electro-Fenton. • Fe2+- tetrapolyphosphate has a relative higher OH generation ability. • Absolute rate constant for oxidation of SMR by OH= (3.4 ± 0.09) × 109 M−1 s−1. • DFT suggested hydroxylation of SMR was dominant during its oxidation degradation. A nickel-foam cathode modified by a self-nitrogen-doped biochar derived from waste giant reed was synthesized. The fabricated cathode (B@Ni-F) proved to be with high oxygen reaction reactive (ORR) reactivity and H 2 O 2 selectivity (70.41%) owing to the enrichment of oxygen functional groups and pyridinic N when low-temperature pyrolyzed biochar was incorporated. The charge transfer resistance of B@Ni-F decreased to 7.18 Ω, which was 95.7 Ω for the original nickel-foam, proving by electrochemical impedance spectroscopy (EIS). Expectedly, Its H 2 O 2 accumulation improved 14 times, thus making it comparable with commonly used electrodes like carbon cloth and graphite plate. Subsequently, B@Ni-F cathode and iron-foam (Fe-F) catalyst were firstly used in the electro-Fenton (EF) process for sulfamerazine (SMR) degradation. Double-functional polyphosphate electrolytes including tetrapolyphosphate (4-TPP), tripolyphosphate (3-TPP), pyrophosphate (PP) and Na 3 PO 4 were compared with the conventional Na 2 SO 4 electrolyte in EF for SMR degradation. The absolute rate constant for oxidation of SMR by OH was determined to be (3.4 ± 0.09) × 109 M−1 s−1. SMR degradation enhancement in the presence of polyphosphate-based electrolytes is associated with bulk OH generation from Fe2+- polyphosphate ligand complexes via O 2 activation. The Fe2+-3-TPP complexes have relatively higher oxidation ability compared to Fe2+-PP, Fe2+-PO 4 species. A plausible SMR oxidation pathway is proposed based on the by-products detected by UPLC-MS/MS and density functional theory (DFT) calculations. The dominant SMR degradation pathway was hydroxylation of aniline residue of SMR, followed with the cleavage of S N and then breakage of aromatic rings. [ABSTRACT FROM AUTHOR]