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We report the ultrafast synthesis of WO 3 nanosheet array photoanode on fluorine-doped tin oxide-coated glass without a seed layer by microwave-assisted deposition route. The ultrafast microwave-assisted synthesis at various microwave deposition cycles resulted in tailored WO 3 morphologies with a monoclinic structure. The photoanode growth mechanism and effect of morphology tuning on the photoelectrochemical activities of WO 3 photoanodes were studied in detail. Under one sun irradiation, the microwave-assisted WO 3 photoanode prepared at four cycles (WO 3 -4 MW) exhibited a photocurrent density of 1.1 mA/cm2 at 1.0 V versus Ag/AgCl, whereas the WO 3 photoanode prepared at two cycles (WO 3 -2 MW) achieved 0.68 mA/cm2. Further, hydrogen treatment of optimum WO 3 -4 MW photoanodes at 300 °C, 20 min and exhibited a high photoelectrochemical (PEC) degradation efficiency of Orange II dye (∼99 %/180 min) and BPA (98.5 % in 30 min). Additionally, ∼97 % E. Coli bacterial PEC inactivation was achieved within 120 min over H 2 -WO 3 -4 MW under one sun illumination irradiation. Also, plausible charge recombination/separation processes in microwave-assisted WO 3 /FTO and H 2 -WO 3 -4 MW photoanodes were also reported. [Display omitted] • The WO 3 -4 MW was developed via a simple surfactant-free microwave- process. • A growth mechanism is proposed for WO 3 -4 MW photoanodes. • WO 3 -4 MW achieved two times photocurrent 1. 1 mA/cm2 than WO 3 -2 MW. • H 2 -WO 3 -4 MW exhibited 97 %, 98.5 % decomposition efficiency for E. coli - and -BPA pollutants. • The charge transfer processes in H 2 -WO 3 -4 MW photoanodes are well proposed. [ABSTRACT FROM AUTHOR]

The present study focuses on controlling the composition of microwave-fabricated tungsten oxide (WO 3) nanoparticles through annealing at 500 °C. The significance of annealing on the surface oxygen states and the photocatalytic performance of WO 3 nanoparticles were systematically investigated for the removal of organic pollutants and bacteria. The optimum photocatalyst, microwave-assisted WO 3 which was successively annealed for 6 h and Pt-loaded (Pt/WO 3 -M-6 h) demonstrated high photocatalytic performances in inactivation (99 %) against E. coli and S. aureus as well as in degradations of Orange II dye (93 %) and BPA (99 %) under one sun illumination for 180 min. The integration of WO 3 -M-6 having a moderate amount of surface oxygen defects and Pt loading could provide the most favorable environment in charge transfer by reducing the electron-hole recombination and as an electron collector, respectively. Detailed mechanisms have been proposed for the photocatalytic decomposition of organic pollutants and the photocatalytic disinfection of waterborne bacteria. [Display omitted] • WO 3 nanoarchitectures were developed via a simple surfactant-free microwave- process. • Correlation between crystalline structure and photocatalytic performance of WO 3 nanoarchitectures was studied in detail. • Pt/WO 3 -M-6 h exhibited 93 % orange II dye and 99 % BPA decomposition efficiency within 180 min • 99 % PC antibacterial activity was achieved for optimum Pt/WO 3 -M-6 h photocatalyst. • Two charge transfer processes during organic decomposition and E. coli inactivation are well proposed. [ABSTRACT FROM AUTHOR]

Microwave-assisted WO 3 photoelectrodes have been rarely studied in terms of their growth mechanism and photoelectrochemical (PEC) application for energy generation and waste water organic pollutants removal. Microwave-assisted rapid synthesis technique is proposed in the current study as a means of reducing the deposition time of tungsten oxide nanosheets on tungsten foil. XRD and PEC studies indicate that WO 3 -NS photoanodes with an active (002) plane exhibited optimal PEC performance, whereas (020) suffered from charge carrier separation during the prolongation of microwave cycles from 1 to 5. Under 1.5 G simulated sunlight, 100 mWcm2, the optimum WO 3 -MW-3 cycle photoanode has a maximum photocurrent density of 1.68 mA cm2 at 1.0 V vs. Ag/AgCl compared to the transparent conducting WO 3 /FTO substrates. The optimum morphology and large specific surface areas of WO 3 -NS's lead to enhanced charge separation in WO 3 -MW-3 cycle photoanodes. The WO 3 -MW-3 cycle photoanodes demonstrated 71 and 41 μmol of H 2 and O 2 evolution, respectively, within 180 min, while degradation of PEC orange II dye reached 98.5%. The microwave-induced systems can be used to produce a wide variety of nanostructured photoanodes for photovoltaics and electrocatalysis. Herein, for the first time, we successfully synthesized WO 3 nanosheets (WO 3 -NSs) on W foil within a short time period using microwave radiation and demonstrated the PEC stability for PEC water splitting and Orange II dye degradation under one-sun illumination without any surfactants. [Display omitted] • Highly stable microwave assisted WO 3 nanosheets photoelectrode was synthesized. • WO 3 -MW-3 cycle photoanode with (002) facets exhibited a photocurrent density of 1.68 mA cm−2 at 1.0 V vs. Ag/AgCl. • The WO 3 -PEC system was constructed for water splitting and orange II dye degradation. • Charge transfer mechanism in morphology-controlled microwave assisted WO 3 is well proposed. [ABSTRACT FROM AUTHOR]

The effects of the temperature and the presence of an interfacial buffer layer on the nanostructure of organic bulk heterojunctions (BHJs) based on copper phthalocyanine (CuPc) and fullerene (C60) systems were examined using real-time in situ X-ray measurements. The CuPc:C60 BHJ structures prepared without a buffer layer formed a standing-on configured γ-CuPc phase. Once formed, the γ-phase could be rendered thermally stable by post-annealing at 180°C. The insertion of a CuI buffer layer prior to the deposition of a CuPc:C60 BHJ layer induced the formation of a lying-down configured CuPc phase in the BHJ layer. The CuPc peak intensity and lattice parameters gradually increased upon thermal annealing. This increase in intensity appeared to be related to the strain at the interface between the CuPc:C60 and CuI layers. [ABSTRACT FROM AUTHOR]

Multi-component (ternary, quaternary, and beyond) bulk heterojunction (BHJ) active layers are considered one of the most effective ways of increasing the performance of organic photovoltaics (OPVs). Herein, an alternative sequential deposition method for the development of efficient multi-component OPVs without the need for the complex optimization steps typical for blend parameters is discussed. Simple sequential spin-coating of two binary donor:acceptor blends was applied to produce modified quaternary BHJ layers, making full use of the optoelectronic advantages offered by the two binary blends and their optimized morphological features. A combination of theoretical and experimental analyses revealed the occurrence of molecular reorganization during sequential deposition which facilitated self-optimized molecular stratification and cascade energy level alignment. By using expanded universality test to account for the diverse BHJ systems, this sequential deposition methodology creates new opportunities as an alternative fabrication platform to secure high-performance multi-component BHJ OPVs for versatile (i.e., indoor and outdoor) irradiation environments while overcoming many of the drawbacks of conventional manufacturing procedures. Image 1 • Alternative manufacturing process of organic photovoltaics (OPVs) is demonstrated. • Sequential spin-coating of two binary blends produces modified multi-component bulk heterojunction layers. • Performance is optimized for both indoor and outdoor light conditions without the need for fine-tuned blend optimization. • Sequential deposition is a universal platform to achieve optimization-free, high-performance multi-component OPVs. [ABSTRACT FROM AUTHOR]

Inevitable frictional heat, generated by friction, degrades output performance of polymer-based triboelectric nanogenerators (TENGs). To address this issue, we propose to take advantage of using shape memory effect of polyurethane (PU) as a triboelectric layer to not only operate TENG sustainably, but also realize self-boosting power generation performance of TENG by frictional heat. We found that frictional heat sufficiently leads to the glass transition of PU and this transformed PU at elevated temperature contributes to change key parameters, serving to improve performance of TENG, including dielectric constant, work function, and charge trap density. In this work we verified PU harness heat generated by friction and demonstrated 300% increase of the power-generating performance of PU-based TENG with experiencing the glass transition. In addition, we experimentally observed no further temperature elevation around 60 °C in TENG with a continuous rotating friction mode, which offers PU potential to be a promising triboelectric material for high performance TENGs. We demonstrate the self-boosted output performance of triboelectric nanogenerator (TENG) with polyurethane (PU) as a triboelectric polymer. Output perfomance of PU-based TENG can be significantly enhanced by the friction-heat-induced property change of PU such as dielectric constant, work function, and trap site density. In addition, we experimentally observed the output performance PU-based TENG is stable due to self-limited temperature increase up to 60 °C by glass transition in the continuous friction process. Image 1 • We introduce an intriguing approach to overcome a power degradation of triboelectric nanogenerators (TENGs) induced by a temperature rise due to friction heat. • Our findings show that polyurethane (PU) undergoes a glass transition at 55 °C, which gives rise to improve thereof dielectric constant, work function, and trap site density. • We confirmed that the output performance of PU-based TENG was improved by 300% during operating TENG without any help of additional device and temperature of PU-based TENG is self-stabilized around 60 °C after temperature increase up to around 80 °C in the free-standing rotation mode with the continuous friction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Slow crystallization for high oriented perovskite crystals in ambient air. • 18.56% of MAPbI 3 PV has been achieved under the optimal air-process condition. • Optimal device retained over 90% of initial performance after 914 h in dry air. Although the efficiency of inorganic-organic perovskite solar cells (PSCs) has increased significantly owing to intermediate phase induced slow crystallization using dimethyl sulfoxide (DMSO) as a co-solvent in N 2 -filled glovebox, PSCs are generally fabricated in ambient air via a fast crystallization process to protect the perovskite layer from H 2 O or O 2. In this study, we suggest a possibility of slow crystallization process for MAPbI 3 perovskite crystals via intermediate phase formation by adjusting the humidity of air at RH 20%–30%. We obtained high-quality perovskite grains by implementing the slow crystallization process using an antisolvent and the ratio of PbI 2 :MAI:DMSO in the precursor solution at RH 20%–30%. The amount and state of the intermediate phase inside the as-deposited film were analyzed by grazing incidence wide-angle X-ray scattering (GIWAXS) measurements. The deposited perovskite layer with the pure intermediate via extremely slow crystallization showed higher absorption, fewer grain boundaries, and suppressed defect recombination losses than the fast crystallized perovskite phase. Thus, we obtained higher stability and high power conversion efficiency of up to 18.56% in a p-i-n-structured MAPbI 3 -based perovskite solar cell under ambient air with RH 20%–30%. [ABSTRACT FROM AUTHOR]

A simple and effective strategy was used to fundamentally improve the performance of a heterostructured Ni(OH) 2 /CdS/ZnIn 2 S 4 /TiO 2 photoanode. TiO 2 nanorods grown hydrothermally on fluorine-doped tin oxide (FTO) and annealed at 500 °C yielded an optimal photocurrent density of ~988 μA cm –2 at 0.1 V vs. Ag/AgCl under simulated illumination conditions. The annealing process minimized the defects in TiO 2 and assisted in the formation of close contacts between the FTO and TiO 2 nanorods, which allowed for efficient electron transport. The stepwise introduction of ZnIn 2 S 4 and CdS on annealed TiO 2 enhanced absorption in the visible range and electron/hole separation in CdS/ZnIn 2 S 4 /TiO 2 . Additionally, the Ni(OH) 2 cocatalyst functioned in hole trapping and improved the stability of the photoelectrode through timely consumption of the photogenerated charges, particularly the holes. [ABSTRACT FROM AUTHOR]

Increasing multidrug-resistant pathogenic microbial around the world become a global problem, making it imperative to develop effective methods for bacterial inactivation in wastewater. In this study, we propose a multifunctional photoelectrochemical (PEC) system to successfully disinfect microbial cells and degrade orange (II) dyes. CoO x NP were synthesized by spin-coating onto hydrothermally synthesized TiO 2 nanorod arrays followed by electrodeposited NiFe-LDH to develop the NiFe-LDH/CoO x NP-TiO 2 NRs. Interestingly, spin-coated CoO x NP-TiO 2 NRs exhibited a 1.5-fold enhancement in photocurrent (1.384 mA/cm2) than pristine TiO 2 NRs (0.92 mA/cm2). A NiFe-layered double hydroxide (LDH) cocatalysts layer further exhibits the maximum photocurrent density of 1.64 mA/cm2 with IPCE of 84.5% at 1.0 V Ag/AgCl at 380 nm. Furthermore, NiFe-LDH/CoO x -TiO 2 NR photoanodes were effectually employed for photoelectrochemical bacteria disinfection and organic pollutant removals. With NiFe-LDH/CoO x -TiO 2 NR, 99% (120 min) bacterial inactivation and 99% (60 min) orange II dye decomposition efficiency was achieved. Superoxide radicals (−O 2 •), hydroxyl radicals (HO•), and holes (h+) played a critical role in the PEC degradation systems. Due to the synergy between NiFe-LDH cocatalyst and CoO x interlayer, surface water oxidation reactions were accelerated over NiFe-LDH/CoO x NP-TiO 2 NRs. The charge transport process in NiFe-LDH/CoO x NP-TiO 2 NRs photoanode-based PEC system was proposed in detail. Here, NiFe-LDH/CoOx NP-TiO 2 NRs were synthesized by three step approach and achieved 1.64 mA/cm2 further photocurrent density with 99% (120 min) bacterial inactivation and 99% (60 min) orange II dye decomposition efficiency under one sun illumination. [Display omitted] • Surface-tailored NiFe-LDH photoanodes were synthesized by successive spin coating and electrodeposition. • NiFe-LDH photoanodes exhibited 1.78 times photocurrent density (1.64 mA/cm2) than the TiO 2 NR. • Surface-tailored NiFe-LDH achieved 99% (120 min) bacterial inactivation. • The synergy between NiFe-LDH and CoO x led to 99% (60 min) degradation of orange II dye. • The charge transport process in NiFe-LDH/CoO x NP-TiO 2 NRs photoanode is studied in detail. [ABSTRACT FROM AUTHOR]

Here, we report the synergistic effect of dual TiO 2 layers to enhance the PEC performance of Zirconium-doped zinc ferrite (ZZFO) photoanode by improving the charge carrier density and suppressing the photogenerated charge recombination. The TiO 2 underlayer works as a blocking layer to remarkably suppress the back-injection of electrons from the fluorine-doped tin oxide (FTO) leading to reducing the bulk charge recombination. While interlayer TiO 2 improves the bulk charge transfer property of ZZFO photoanodes. The optimal TiO 2 double-layer modified ZZFO photoanode exhibits an enhanced photocurrent of 0.435 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE), which is 2.5 times higher than that of the ZZFO photoanode. The effect of each layer was deeply investigated by electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS) and time-resolved photoluminescence studies (TRPL) with the aim of gaining a clear picture of the interface modifications and their impact on the efficiency of the ZZFO photoanode. [Display omitted] • The effect of TiO 2 double-layer on Zr-doped ZnFe 2 O 4 photoanode is investigated. • Ti diffusion/doping effectively suppressed the charge recombination. • TiO 2 underlayer served as a barrier layer for electron back-injection. • TiO 2 interlayer promoted the spinel inversion structure to aid charge separation. • TiO 2 double-layer constructively improved the photoelectrochemical properties. [ABSTRACT FROM AUTHOR]

The optical glow of ceramics that becomes established during the constant state of flash, known as Stage III in flash sintering experiments, is investigated. The specimen temperature in this state is obtained from in situ experiments at the Pohang Light Source II. The measurements of the specimen temperature agree very well with the predictions from the black body radiation model. The optical emission spectrum from the specimen is measured from the visible into the deep infrared, and compared with black body radiation that would have been expected from Joule heating. It is concluded that the specimens radiate by electroluminescence, which is ascribed to electron–hole recombination of excitons. The phenomenon is likely the same as discovered by Nernst at the turn of the twentieth century. [ABSTRACT FROM AUTHOR]

Ex-situ doping into hematite films is carried out via a short-duration (∼60 s) microwave-assisted metal-ions attachment (MWMA) of tetravalent Zr4+ ion on the surface of FeOOH/FTO, followed by high temperature annealing (HTA) to fabricate Zr4+:Fe 2 O 3 /FTO photoanode for photoelectrochemical (PEC) water splitting. Compared to a simple dipping attachment without microwave irradiation, this MWMA allows a much larger amount of attached Zr4+-ions on the FeOOH precursor, leading to a properly doped photoanode of much higher PEC activity. The primary effect of Zr4+ doping is to improve the charge transport characteristics in the bulk of hematite. In addition, it also boosts charge injection efficiency at the semiconductor and electrolyte interface by forming an inadvertent passivation layer and promoting hole transfer via surface states. As a result, the Zr4+:Fe 2 O 3 /FTO photoanode shows a higher photocurrent density of 1.54 mA cm−2 at 1.23 V RHE under 1 Sun irradiation relative to undoped Fe 2 O 3 /FTO (1.02 mA cm−2) or Zr4+:Fe 2 O 3 /FTO (1.19 mA cm−2) prepared without MWMA. Microwave irradiation energized the suspended Zr4+ ions to give a higher coverage on the FeOOH film for effective doping of hematite photoanode. The Zr-doping improves not only bulk charge transport properties, but also boosts charge injection performance at the semiconductor-electrolyte interface by forming an inadvertent passivation layer and promoting hole transfer via surface states. [Display omitted] [ABSTRACT FROM AUTHOR]

Boron doping with an adequate concentration is highly desirable for alloy development because it profoundly improves the material's interface cohesion via interfacial segregation. However, scientific and applicable potentials of soluble boron that resides at the alloy internal grains are generally overlooked. Here we report a strategy for overcoming the typically low strengths of face-centered cubic high-entropy alloys (HEAs) through exploiting soluble boron instead of the interfacial boron. We find that soluble boron increases stress/strain field at the recrystallized HEA grain structure, leading to the generation of short-range order (SRO) in those deformation structure under load at 77 K. The highly increased degree of SRO at planar dislocation slip band that forms during straining, proved by electron microscopy and synchrotron X-ray diffraction, strengthens a typical non-equimolar Fe 40 Mn 40 Co 10 Cr 10 (at%) HEA, particularly increasing yield strengths by ∼32%, to ∼1.1 GPa compared to those of boron-free reference materials with similar grain sizes. The advent of deformation-induced SRO domains causes severe lattice distortion (specifically, contraction), leading to the increased cryogenic yield strength of ∼210 MPa, but generating micro-voids at grain boundaries. This study on deformation-induced SRO via boron advances the fundamental understanding of SRO impacts on HEA grains and mechanical properties at cryogenic temperatures, which may pave a general pathway for developing a wide range of ultrastrong alloys for cryogenic applications. Image, graphical abstract [ABSTRACT FROM AUTHOR]

In this study, in situ silver (Ag) - porous ZnO photocatalysts were synthesized via solvothermal and post-annealing treatment. The formation of the porous ZnO structure due to the removal of organic moieties from the inorganic–organic hybrids Ag-ZnS(en) 0.5 during the annealing process. The optimal Ag–ZnO photocatalyst showed excellent photocatalytic degradation activity, with 95.5% orange II dye and 97.2% bisphenol A (BPA) degradation under visible light conditions. Additionally, the photocatalytic inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) led to a 97% inactivation rate after 2 h under dark conditions. Trapping experiments suggest that the superoxide anion (▪O 2 −) radicals are the main active species to degrade the organic dye. The improved photocatalytic dye degradation activity and inactivation of bacteria were attributed to the synergistic effect of Ag and porous ZnO structure, increased surface area, and efficiently separated the photoexcited charge carriers. This work could provide an effective strategy for the synthesis of porous structures toward organic pollutant degradation and bacterial inactivation in wastewater. [Display omitted] • In situ porous Ag–ZnO photocatalyst is fabricated via solvothermal and post-heat treatment. • The optimal photocatalyst showed superior photocatalytic dye degradation and antibacterial activity. • Different active species are responsible for dyes degradation are discussed. • Lastly, photocatalytic dye degradation and antibacterial mechanism are well studied. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting by semiconductor photoanodes is limited by sluggish water oxidation kinetics coupled with serious charge recombinations. In this paper, an effective strategy of TiO 2 nanorod/nanotube nanostructured interface reconstruction, oxygen vacancies and surface modification were employed for stability and efficient charge transport in the photoanodes. Successive anodization and hydrothermal routes were adopted for the TiO 2 NR/NT photoanodes interface reconstruction, followed by Au nanoparticles/clusters (Au NP) loading and hydrogen treatment. This resulted in H–Au–TiO 2 NR/NT photoanodes. A three-dimensional structure of TiO 2 NR on TiO 2 NT/Ti foil nanotubes achieved the highest photocurrent density (1.42 mA cm−2 at 0.3 V vs. Ag/AgCl). The optimal oxygen vacancies and Au NP loading on TiO 2 NR/NT exhibited 1.62 mA cm−2 photocurrent density at 0.3 V vs. Ag/AgCl in H–Au–TiO 2 NR/NT photoelectrode, which is eight times higher than the TiO 2 NT/Ti foil. TRPL analyses confirm the hydrogen treatments to TiO 2 exhibited the emission lifetime (46 ns) in the H–Au–TiO 2 NR/NT photoanodes due to newly formed lower Ti3+-related trapped electron states and Au NP. The optimum H–Au (4)–TiO 2 NR/NT photoanodes achieved 95% photoelectrochemical (PEC) bacterial inactivation and effective PEC water splitting with (278 and 135.4) μmol of hydrogen and oxygen generation, respectively. In this study, oxygen vacancies combined with gold particles and interface reconstruction provide an innovative way to design effective photoelectrodes. [Display omitted] • H–Au–TiO 2 NR/NT photoanodes have been fabricated via anodization and post treatments. • TiO 2-x was efficaciously projected on TiO 2 NR/NT photoanode via hydrogenation. • Au NP and TiO 2-x synergism significantly accelerated the charge transfer in H–Au–TiO 2 NR/NT. • H–Au (4)–TiO 2 NR/NT exhibits an eight times photocurrent boost than TiO 2 NT/Ti foil. • H–Au (4)–TiO 2 NR/NT photoanodes achieved 95% bacterial inactivation and effective PEC water splitting. [ABSTRACT FROM AUTHOR]

Herein, we report the surface treatment on Zr4+/Al3+ codoped α-Fe 2 O 3 photoanode for high-performance photoelectrochemical water splitting. A high-temperature quenching exhibits the Zr4+/Al3+ codoping in α-Fe 2 O 3 photoanode without damaging morphology. The presence of Zr4+/Al3+ codoping shows a cathodic shift in onset potential, but lack of increment in photocurrent reveals the major role of passivation and the minimum doping effect of aluminum. Additionally, CoO x cocatalyst exhibits increment in photocurrent with the greater cathodic shift in onset potential than the pristine α-Fe 2 O 3 nanorods. The CoO x surface-reworked Zr4+/Al3+ codoped α-Fe 2 O 3 photoanode displays the highest photocurrent of 1.5 mA/cm2 at 1.23 V vs. RHE (76% increment over the pristine α-Fe 2 O 3) and 0.7 mA/cm2 at 1.0 V vs. RHE (102% increment over the pristine α-Fe 2 O 3). The systematic characterization carried out using x-ray diffraction and scanning electron microscopy confirms that after Zr4+/Al3+ codoping, and surface treatment, the crystalline structure, and morphology of the photoanodes remains unchanged. X-ray photoelectron spectroscopy confirmed the existence of Zr4+/Al3+ codopants in the hematite nanostructure. The electrochemical properties of the photoanode suggest that Al3+ and Zr4+ codoping, as well as surface treatment with CoO x , cocatalyst lowers charge transfer resistance across the FTO/hematite interface, and hematite/electrolyte interface. This designs not only lowers onset potential but also offers the blueprint for the development of an efficient catalyst for solar water oxidation. CoO x surface-reworked Zr4+/Al3+ codoped α-Fe 2 O 3 photoanode displays the 102% increment in PEC performance than pristine α-Fe 2 O 3 at 1.0 V vs. RHE. Image 1 • Zr4+/Al3+-codoped Fe 2 O 3 photoanode synthesized by hydrothermal method. • CoO x co-catalyst improves the OER kinetics via surface reworking. • Optimum photoanode exhibits 102% increase in photocurrent density than Fe 2 O 3. • The charge transfer mechanism in 6% Zr + 6% Al + 15 mM Co is also proposed. [ABSTRACT FROM AUTHOR]

Hydrothermal and wet impregnation methods are presented in this study for synthesizing CoO x (1 wt%)/Sn/Zr-codoped Fe 2 O 3 nanorod photocatalysts for the degradation of organic pollutants and deactivation of bacteria. A hydrothermal route was used to synthesize self-assembled rod-like hierarchical structures of Sn(0–6%) doped Zr–Fe 2 O 3 NRs. Additionally, a wet impregnation method was used to load CoO x onto the surface of photocatalysts (Sn(0–6%)-doped Zr–Fe 2 O 3 NRs). A series of 1 wt% CoO x modified Sn(0–6%)-doped Zr–Fe 2 O 3 NRs were synthesized, characterized, and utilized for the photocatalytic decomposition of organic contaminants, along with the killing of E. coli and S. aureus. In comparison with 0, 2, and 6% Sn co-doped Zr–Fe 2 O 3 NRs, the CoO x (1 wt%)/4%Sn/Zr–Fe 2 O 3 NRs photocatalyst exhibited an E. coli and S. aureus inactivation efficiencies (90 and 98%). A bio-TEM study of treated and untreated bacterial cells revealed that the CoO x (1 wt%)/4%Sn/Zr–Fe 2 O 3 NRs photocatalyst led to considerable changes in the bacterial cell membranes' morphology. The optimal CoO x (1 wt%)/Sn(4%) co-doped Zr–Fe 2 O 3 NRs photocatalyst achieved degradation efficiencies of 98.5% and 94.6% for BPA and orange II dye, respectively. As a result, this work will provide a facile and effective method for developing visible light-active photocatalysts for bacterial inactivation and organic pollutants degradation. [Display omitted] • In-situ Sn/Zr-codoped Fe 2 O 3 NRs catalyst has been developed via a hydrothermal approach. • The effect of Sn co-doping on the properties of Zr–Fe 2 O 3 NRs was systematically studied. • CoO x (1 wt%) catalysts were wet impregnated on the in-situ Sn/Zr-codoped Fe 2 O 3 NRs. • CoO x (1 wt%)/ in-situ Sn/Zr-codoped Fe 2 O 3 NRs achieved 90 and 98% E. coli and S. aureus inactivation efficiency. • Photo-Fenton reaction pushed 94.6%, 98.5% of orange II dye, and BPA degradation under λ ≥ 420 nm. [ABSTRACT FROM AUTHOR]

We found that micro-cells surrounded by nanowalls can be formed by a maskless wet-etching process on Si (100) surfaces possessing Laser Induced Periodic Surface Structure (LIPSS) by femtosecond laser irradiation. The LIPSS process could produce periodic one-dimensional micron scale ripples on a Si surface, which could be developed into micro-cells by a subsequent etching process. The solution etching conditions strongly affected both the micro-cell and nanowall shapes such as the height and the thickness of nanowalls. The tetramethylammonium hydroxide solution created thin nanowalls and the resulting micro-cells with a well-flattened bottom while the KOH solution formed thick walls and incomplete micro-cells. The bottoms of micro-cells surrounded by the nanowalls were considerably flat with a 3.10 nm surface roughness. A pentacene layer was deposited on the micro-cells of a Si surface to evaluate the film properties by grazing incidence wide angle x-ray scattering measurements. The pentacene film on the micro-cell Si surface showed a strong film phase, which was comparable to the film phase grown on the atomically flat Si surface. [ABSTRACT FROM AUTHOR]

In this paper, the influence of tetravalent dopants such as Si 4+ , Sn 4+ , Ti 4+ , and Zr 4+ on the hematite (α-Fe 2 O 3 ) nanostructure for enhanced photoelectrochemical (PEC) water splitting are reported. The tetravalent doping was performed on hydrothermally grown akaganeite (β-FeOOH) nanorods on FTO (fluorine-doped tin-oxide) substrates via a simple dipping method for which the respective metal-precursor solution was used, followed by a high-temperature (800° C) sintering in a box furnace. The photocurrent density for the pristine (hematite) photoanode is ∼0.81 mA/cm 2 at 1.23 V RHE , with an onset potential of 0.72 V RHE ; however, the tetravalent dopants on the hematite nanostructures alter the properties of the pristine photoanode. The Si 4+ -doped hematite photoanode showed a slight photocurrent increment without a changing of the onset potential of the pristine photoanode. The Sn 4+ - and Ti 4+ -doped hematite photoanodes, however, showed an anodic shift of the onset potential with the photocurrent increment at a higher applied potential. Interestingly, the Zr 4+ -doped hematite photoanode exhibited an onset potential that is similar to those of the pristine and Si 4+ -doped hematite, but a larger photocurrent density that is similar to those of the Sn 4+ - and Ti 4+ -doped photoanodes was recorded. The photoactivity of the doped photoanodes at 1.23 V RHE follows the order Zr > Sn > Ti > Si. The onset-potential shifts of the doped photoanodes were investigated using the Ab initio calculations that are well correlated with the experimental data. X-ray diffraction (XRD) and scanning-electron microscopy (FESEM) revealed that both the crystalline phase of the hematite and the nanorod morphology were preserved after the doping procedure. X-ray photoelectron spectroscopy (XPS) confirmed the presence of the tetravalent dopants on the hematite nanostructure. The charge-transfer resistance at the various interfaces of the doped photoanodes was studied using impedance spectroscopy. The doping on the hematite photoanodes was confirmed using the Mott-Schottky (MS) analysis. [ABSTRACT FROM AUTHOR]

Carbon-supported Pt and PtNi nanoparticles (NPs) were synthesized using a borohydride reduction method. Structural properties were studied by synchrotron X-ray diffraction (XRD) and the size/shape of the NPs was determined by transmission electron microscope (TEM). X-ray absorption spectroscopy with its two amendments; X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), has been employed to investigate the local electronic/atomic structure surrounding the Pt and Ni atoms. XANES results, at Pt L 3 -edge and Ni K-edge, have shown fractional oxidation of Pt and Ni atoms. The Pt3Ni1NPs have exhibited a lower bond distance of Pt–Ni shell and higher coordination number of Pt–Ni shells, indicating the alloy formation between Pt and Ni. We further have demonstrated that the Pt and PtNi NPs can serve as effective photocatalysts towards the degradation of water pollutant dye (methyl orange (MO)). By considering the interband charge-transfer of Pt (5d →6sp), a tentative mechanism is proposed to understand the photocatalytic degradation of MO dye molecules by Pt/PtNi NPs under the light irradiation. [ABSTRACT FROM AUTHOR]

The process of photoelectrochemical wastewater detoxification is limited by significant charge recombination, which is difficult to suppress with efficient single-material photoanodes. We demonstrated the effectiveness of hydrogen treatment in evaluating charge separation properties in WO 3-x /TiO 2-x NT/Ti foil heterojunction photoanodes. The influence of varying hydrogen annealing (200–400 °C) on the structural and photoelectrochemical properties of WO 3 /TiO 2 NS/NT heterojunction is studied systematically. Additionally, after hydrogen treatment of pristine WO 3 /TiO 2 NT/Ti foil photoanodes, substoichiometric H-WO 3-x /TiO 2-x NT-300 achieved the 1.21 mA/cm2 photocurrent density, which is 8.06 and 3.27 times than TiO 2 NT and WO 3 /TiO 2 NT. The hydrogen-treated H-WO 3-x /TiO 2-x NT-300 electrode exhibits 3 times greater bulk efficiencies than the WO 3 /TiO 2 NT electrode due to the production of oxygen vacancies at the interface. Additionally, optimum H-WO 3-x /TiO 2-x NS/NT-300 photoanode exhibited 93.8% E. coli and 99.8% BPA decomposition efficiencies. The present work shows the effectiveness of microwave-assisted H-WO 3-x /TiO 2-x NT heterojunction photoanodes for organic decomposition and antibacterial activity in a neutral environment without surface-loaded co-catalysts. Here, for the first time, we develop H-WO 3-x /TiO 2-x NT/Ti foil-based photoanodes by a simple microwave and anodization process. The optimum H-WO 3-x /TiO 2-x NT-300 exhibited 93.8% and 99.8% E. coli and BPA degradation in 180 min. Additionally, optimum photoanode achieved 8.06 times higher photocurrent density (1.21 mA/cm2) than TiO 2 NT. [Display omitted] • H-WO 3-x /TiO 2-x NT/Ti was developed via a simple surfactant-free microwave-process. • PEC performance is enhanced by cooperation of defects and TiO 2-x transport channels. • H-WO 3-x /TiO 2-x NT-300 displayed 8 times higher photocurrent density than TiO 2 NT. • 93.8% E. coli and 99.8% BPA decomposition efficiency within 180 min. • The charge transfer mechanism in H-WO 3-x /TiO 2-x NT-300 during PEC is well proposed. [ABSTRACT FROM AUTHOR]

Herein, we synthesized in-situ Zr-doped Fe 2 O 3 NRs photocatalyst by successive simple hydrothermal and air quenching methods. The synergistic roles of CoO x (1 wt%) and Zr-doping on bacteria inactivation and model organic pollutants over Fe 2 O 3 NRs photocatalyst were studied in detail. Initially, rod-like Zr ((0–8) %)-doped Fe 2 O 3 NRs were produced via a hydrothermal method. CoO x was loaded onto the Zr ((0–8) %)-doped Fe 2 O 3 NRs) surface by a wet impregnation approach. The Zr-doping conditions and CoO x loadings were judiciously optimized, and a highly photoactive CoO x (1 wt%)/Zr(6%)-doped Fe 2 O 3 NRs photocatalyst was developed. The CoO x (1 wt%) loaded Zr(6%)-doped Fe 2 O 3 NRs photocatalyst revealed 99.4% inactivation efficiency compared with (0, 4 and 8)% Zr-doped Fe 2 O 3 NRs, respectively. After CoO x (1 wt%)/Zr(6%)-doped Fe 2 O 3 NRs photocatalyst treatment, Bio-TEM images of bacterial cells showed extensive morphological deviations in cell membranes, compared with the non-treated ones. Additionally, the optimum CoO x (1 wt%)/Zr(6%)-doped Fe 2 O 3 NRs photocatalyst exhibited 99.2% BPA and 98.3% orange II dye degradation after light radiation for 3 h. This work will provide a rapid method for the development of photostable catalyst materials for bacterial disinfection and organic degradation. [Display omitted] • In-situ Zr-doped Fe 2 O 3 NRs photocatalyst has been developed via a hydrothermal approach. • CoO x loaded onto Zr ((0–8)%)-doped Fe 2 O 3 NRs) surface by a wet impregnation approach. • Synergistic roles of CoO x (1 wt%) and Zr-doping on bacteria inactivation and organic pollutants were studied in detail. • CoO x (1 wt%)/Zr(6%)-doped Fe 2 O 3 NRs revealed 99.4% E-coli and S. Aureus inactivation efficiency. • Optimum photocatalyst exhibited 99.2% BPA and 98.3% orange II dye degradation within 3 h. [ABSTRACT FROM AUTHOR]

Doping transition metals into 1-D nanostructures is of crucial importance for their application in photovoltaics and photoelectrochemical (PEC) systems; performance enhancements arise from both dopant incorporation and the 1-D nanostructures. Both in-situ and ex-situ doping methods have been demonstrated for 1-D hematite (α-Fe 2 O 3 ) nanostructures, with tin (Sn) as the dopant, for photoelectrochemical water oxidation. In-situ Sn-doped hematite photoanodes adopted a morphology consisting of nanocorals with the (104) plane as the preferred direction of crystal growth. As an alternative solution, ex-situ doping not only preserves the vertically-aligned nanorod morphology but also sustains the preferred orientation of the (110) axis, which is favorable for high conductivity in pristine hematite photoanodes. In-situ Sn-doping was carried out by the same method: Sn precursors were added and dissolved in ethanol during the hydrothermal synthesis. Ex-situ doping was carried out in two stages (during pre-deposition and during high temperature sintering). During pre-deposition, a defined amount of the Sn precursor was introduced near the surface region of the 1-D nanostructure, and the Sn content was controlled by changing the concentration of the precursor solution. In subsequent high temperature sintering (800 °C), the dopant atoms diffused into the hematite lattice to attain the desired doping profile. We found that ex-situ Sn-doping resulted in a 60% increase in the photocurrent while in-situ Sn-doping yielded an increase of only 20% in the photocurrent, as compared with pristine hematite photoanodes, at 1.4 V vs. RHE. The improvement in the photocurrent was caused by a combination of Sn dopants in the hematite, which act as electron donors by increasing the donor density, and better surface charge transfer kinetics, thereby enhancing the overall device performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • β-FeOOH was first prepared on FTO by microwave synthesis within few minutes. • Rapid recrystallization and poly-condensation induces Fe(OH) 3 nucleation on FTO. • Optimum thickness and high-temperature quenching were pivotal to Sn4+ diffusion. • 180 and 91 μmol of H 2 and O 2 generated over FTO/Fe 2 O 3 -1/Co-Pi photoanode. • MAHS strategy opens a novel way to synthesize visible light active photoanode materials. In this study, we describe for the first time the detonated ultrafast growth and functionalization of Iron (III) oxyhydroxide (FeOOH) nanorod array templates on a fluorine-doped tin oxide (FTO) substrate using a specially designed microwave-assisted cost-effective synthesis route. The rapid recrystallization and polycondensation in microwave-assisted synthesis (MAS) led to the controlled growth of ferric-hydroxide Fe(OH) 3 from the iron-hydroxo complex Fe(H 2 O) 3 (OH) 3 formed from hydrolyzed FeCl 3. Further, the dependence of a number of MAS cycles on the growth and evolution of β-FeOOH nanorod array templated photoanode was examined by high-resolution scanning electron microscopy. The formation mechanism with morphology-controlled FeOOH nanostructure was well discussed and verified. Further, high-temperature quenching (HTQ) transformed MAS akaganeite into hematite, and Sn4+ diffused from FTO substrate. Due to the synergistic impact of MAS growth and Sn4+ diffusion in the α-Fe 2 O 3 nanostructure, the optimum FTO/Fe 2 O 3 -1 photoanode achieved the highest photocurrent density (0.854 mA cm−2 at 1.23 V vs. RHE) related with other studied samples. The charge-transfer mechanisms in microwave-assisted Sn4+-diffused α-Fe 2 O 3 nanostructure photoanodes are also investigated. Additionally, the surface-modified FTO/Fe 2 O 3 -1 photoanode exhibited the 91 and 180 μmol of oxygen and hydrogen evolution during photoelectrochemical water splitting, respectively. This work opens a sustainable and feasible strategy for designing and regulating high-efficient novel functional photoanode materials for water splitting. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated thermal stabilization of Co2+-exchanged zeolite X (Coscanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and leaching tests. From SEM-EDX analysis, cobalt was dispersed randomly at ≤600°C, suggesting its presence as an extraframework cation in exchange sites. At ≥800°C, cobalt was locally concentrated with Al on the vitreous surface. Consistent with such observations, XRD data indicated that Coned the zeolite framework at ≤600°C, and that it became vitrified and transformed to nepheline (NaAlSiO4(s)) and cobalt aluminate (CoAl2O4(s)) at ≥800°C. Cobalt-K edge XAS was subjected to both X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) analyses. In XANES spectra, the pre-edge peaks and edge-shoulders, characteristic of 4-fold coordinated cobalt (e.g., CoAl2O4(s)), were not evident at ≤600°C, but such features were strong at ≥800°C. The EXAFS spectra of Co264;600°C lacked in the coordination shells beyond the first CoIn contrast, Co265;800°C showed the EXAFS spectra similar to CoAl2O4(s). Taken together, cobalt was likely present as 6-fold coordinated Co2+ in exchange sites at ≤600°C and mainly incorporated into a non-exchangeable CoAl2O4-like phase in both vitreous and crystalline forms at ≥800°C. In agreement with this proposition, leaching tests with concentrated CaCl2 solutions supported the greater stability of cobalt at ≥800°C. [Copyright &y& Elsevier]

Abstract: Indium-free and acid-resistant anatase Nb-doped TiO2 (NTO) electrodes are promising as economical substitutes for high-cost Sn-doped In2O3 (ITO) films used in organic photovoltaics. By rapid-thermal annealing under an ambient vacuum, an insulating amorphous NTO film of low transparency was changed dramatically into a transparent and conductive anatase NTO electrode. Metallic conductivity of the annealed NTO electrode could be attributed to formation of the anatase phase and activation of the Nb dopant. Based on synchrotron X-ray scattering and high-resolution transmission electron microscopy, the electrical properties of the NTO electrode could be correlated with the microstructure of the NTO film. The acid-stability of NTO film also supports its use as a substitute for ITO electrode. Unlike Ga:ZnO and Al:ZnO films, which were easily etched by acidic PEDOT:PSS solution, the NTO film was stable against this reagent. Importantly, the annealing temperature influenced the performance of the organic solar cell fabricated with the NTO electrode. This indicates that activation of Nb dopants and formation of the anatase phase play an important role in the extraction of carrier from the organic layer to the anode electrode. [Copyright &y& Elsevier]

Abstract: The ambient and high pressure structures of a partially cesium-exchanged K-gallosilicate with a zeolite LTL framework topology (Cs0.65K0.35–GaSi–LTL) was studied using synchrotron X-ray powder diffraction. In contrast to the cation distribution present in the aluminosilicate analogues, the larger cesium cations replace part of the potassium cations in the narrow 8-ring channel as well as in the main 12-ring channel of the gallosilicate LTL. Under hydrostatic pressures mediated by a pore-penetrating alcohol and water mixture, anomalous compression behavior is observed with a slight increase in the unit cell volume upon initial compression, i.e., 0.15% expansion at 0.44GPa. This is the result of the continuous increase of the a-axis length up to 2GPa and is found to be related to the gradual pressure-induced hydration (PIH) occurring inside the main 12-ring channel, where the water content increases from 15.9(1) H2O at ambient conditions to 26.7(1) H2O per formula unit at 2.83GPa. During PIH, part of the cesium cations along the main 12-ring channel migrate into the narrow 8-ring channel. Compared to the structural changes observed in K–GaSi–LTL, the degree of pressure-induced hydration and the accompanying cation migration is found to be diminished in Cs0.65K0.35–GaSi–LTL. [ABSTRACT FROM AUTHOR]

Here, we reported on planar perovskite solar cells (PSCs) which are free of the indium tin oxide (ITO) and electron transport layer (ETL) directly prepared on Nb-doped TiO 2-x (NTO) electrodes. By rapid thermal annealing of NTO film at a temperature of 600 °C under vacuum ambient, we obtained conductive anatase NTO electrodes that act as transparent electrodes and ETL simultaneously in ITO and ETL-free PSCs. The sputtered NTO electrode showed decreasing resistivity with decreasing temperature, indicating metallic conductivity. A planar NTO∖(FAPbI 3) 1-x (MAPbBr 3) x ∖Spiro-MeOTAD∖Au cell showed a power conversion efficiency of 12.50% and open-circuit voltage of 1.08 V in spite of the absence of ETL. The ITO and ETL-free PSC with an NTO electrode exhibited a higher open-circuit voltage of 1.08 V than did an ETL-free PSC with ITO electrode because of effective hole blocking by the NTO electrodes. Our results suggest that sputtered NTO film is a promising multi-functional electrode acting as ETL and transparent electrode simultaneously for achieving simply fabricated and cost-effective PSCs. Image 1 • Nb-doped anatase TiO 2-x (NTO) film which act as ETL and cathode simultaneously in perovskite solar cells (PSCs) is investigated. • The effect of film thickness on the electrical, optical, structural and morphological properties of NTO electrodes is analyzed. • The ETL and ITO-free PSC fabricated on 300 nm-thick NTO electrode exhibits the average PCE of 12.50%. [ABSTRACT FROM AUTHOR]