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CuBi2O4 is a promising p-type semiconductor material with a theoretical maximum current density of about 19.7 mA cm‒2. Although CuBi2O4 has a very high theoretical photocurrent, its poor charge transmission efficiency makes its actual photocurrent far less than its theoretical values. Herein, an in situ modification method is adopted to prepare a photocathode material with Ag as conductive channels. A metal–organic coating method is used to introduce Ag conductive channels, promoting the charge transmission between grains. Ag particles play the role of electrical connection, and improve the separation and transmission of carriers, so as to obtain enhanced photocurrent density. In situ formed Ag conductive channels significantly enhanced the PEC performance of CuBi2O4 photocathodes. [ABSTRACT FROM AUTHOR]

BiVO4 possesses a suitable band gap for photoelectrochemical (PEC) water splitting to produce hydrogen; however, the performance of BiVO4 is limited by several adverse factors. The bulk charge recombination and the slow surface water oxidation reaction of BiVO4 are main unfavorable factors. In view of these disadvantages, an Fe–Bi electrocatalyst is loaded on BiVO4 to improve the PEC performance of BiVO4. After modification, the onset potential of BiVO4 shifts negatively by 60 mV, and the saturated photocurrent is greatly increased. Systematic studies demonstrate that the Fe–Bi electrocatalyst not only enhances the bulk charge separation, but also accelerates the surface water oxidation rate of BiVO4 and greatly reduces the resistance of the reaction interface. [ABSTRACT FROM AUTHOR]

Developing efficient and low-cost electrocatalysts for hydrogen evolution reaction (HER) is important for hydrogen fuel production. In this study, we synthesized two different types of CoS 2 under low sulfur (LS) and high sulfur concentration (HS) conditions. Structural analysis results show that CoS impurity phase forms easily when the concentration of sulfur is low, while at high sulfur concentration the growth of CoS impurity phase is inhibited and leads to phase-pure CoS 2. Electrochemical investigation of HER performance reveals that the onset potential of CoS 2 (HS) electrode (ca. − 0.11 V vs. the reversible hydrogen electrode, RHE) is 30 mV anodic of the CoS 2 (LS) one (ca. − 0.14 V vs. RHE). At a specific current density of 10 mA cm−2 the required overpotential on CoS 2 (HS) electrode is only 163 mV, which is 40 mV less than the CoS 2 (LS) electrode. Electrochemical impedance spectroscopy (EIS) data further demonstrate that the charge transfer rate of CoS 2 (HS) electrode is faster than that of CoS 2 (LS) electrode towards HER. • CoS 2 electrocatalysts with two different nanostructures and stoichiometries are produced. • Sulfur concentration plays a key role in the synthesis of CoS 2. • High sulfur concentration is conducive to reducing the formation of sulfur vacancies. [ABSTRACT FROM AUTHOR]

Exploring cheap and efficient cocatalysts is particularly important for a photoanode during photoelectrochemical (PEC) water splitting. Herein, we demonstrate that composite CoOx/CuO cocatalyst could efficiently enhance the oxygen evolution activity of BiVO4. The onset potential of BiVO4 shifts negatively from 0.42 to 0.38 V vs. the reversible hydrogen electrode (RHE), and the photocurrent of BiVO4 increases from 0.42 mA cm−2 to 1.58 mA cm−2 at 1.23 V vs. RHE, which increases by about 3.76 times. It was confirmed by subsequent electrochemical and physical characterization that the charge separation and injection efficiency were improved, and the IPCE was also improved. Systematic studies indicate that composite CoOx/CuO cocatalyst exhibits better performance than the single CoOx or CuO cocatalyst for promoting the separation of electron‐hole, and accelerating the surface water oxidation reaction. [ABSTRACT FROM AUTHOR]

BiVO has emerged as a promising material for solar water splitting. The poor ability of charge transport and separation always limits its performance for photoelectrochemical water splitting. Herein, we coupled n-type BiVO with p-type LaFeO and LaCoO, achieving a photocurrent more than two times as high as bare BiVO at 1.23 V versus a reversible hydrogen electrode. Also, the onset potential was negatively shifted about 260 mV. The promotion of performance is mainly because the space charge layer in BiVO is broadened, and the band bend is enhanced, which facilitates the separation and transport of photo-generated charges. [ABSTRACT FROM AUTHOR]

Photoelectrochemical oxidation of methyl phenyl sulfide with water as the only oxygen source is achieved on Mo-BiVO 4 photoanode. Mo-BiVO 4 photoelectrode performs oxygen transfer reaction in PEC oxidation of MPS. [Display omitted] • Mo-BiVO 4 photoelectrode was applied to oxidation of methyl phenyl sulfide. • PEC oxygen atom transfer (OAT) reaction was achieved on Mo-BiVO 4 photoelectrode. • Isotopic labelling experiment with H 2 18O revealed oxygen atoms in MPSO were mainly from water. Photoelectrochemical (PEC) selective oxidation is an environment-friendly strategy to obtain value-added chemicals. Herein, we report the PEC oxidation of methyl phenyl sulfide (MPS) into methyl phenyl sulfoxide (MPSO) with 85.7 % selectivity and 36.2 % conversion on molybdenum doped bismuth vanadate (Mo-BiVO 4) photoelectrode under simulated sunlight illumination (AM 1.5 G, 100 mW cm−2). Isotopic labelling experiment with H 2 18O was conducted to clearly reveal that the oxygen atoms in the MPSO were mainly from water. Based on these results, the application of Mo-BiVO 4 has been extended to PEC selective oxidation. [ABSTRACT FROM AUTHOR]

• α-Fe 2 O 3 photoanode was modified by antimony. • Ethylene glycol was an excellent solvent for antimony treatment. • The α-Fe2O3 photoanodes combined with antimony post-treatment showed the best photoelectrochemical performance. The photoelectrochemical (PEC) performance of α-Fe 2 O 3 photoanode suffers from the high carrier recombination rate and the short hole diffusion distance. Enhancing its carrier transport is an important way to improve its performance. In this paper, α-Fe 2 O 3 films were synthesized by hydrothermal method and further optimized by ethylene glycol assisted antimony treatment. Antimony treatment can be divided into pre-annealing and post-annealing treatment. The photocurrent of hematite photoanode post-annealing treated by Sb dissolved in ethylene glycol photoanode can reach to 1.18 mA cm−2, which is 1.6 times higher than that of bare α-Fe 2 O 3 photoanode. The improvement of PEC performance is mainly attributed to the effective inhibition of carrier recombination by antimony treatment. In addition, the slope of the Mott-Schottky curves of Fe 2 O 3 can be obviously changed by antimony treatment, demonstrating the significant increase of carrier concentration. [ABSTRACT FROM AUTHOR]

Bismuth vanadate photoanodes often suffer from poor electron transport, which restricts their photoelectrochemical performance in water oxidation. Here, reduced graphene oxide sheets with excellent electronic conductivity are introduced to bismuth vanadate photoanode films to provide a channel for electron transport. As a result, the charge separation efficiency of the photoanode films increases from 59 to 78 % at 420 nm and 1.23 V (vs. the reversible hydrogen electrode) under back irradiation. In particular, the onset potential for photoelectrochemical water oxidation over reduced graphene oxide-bismuth vanadate photoanode films has a cathodic shift of approximately 120 mV in potassium borate electrolyte compared to bare bismuth vanadate photoanode films. [ABSTRACT FROM AUTHOR]

Environmental problems caused by waste are drawing growing concern worldwide. Such waste problems are even worse in many emerging markets, where waste is frequently mismanaged and thus causes significant environmental problems. To alleviate such waste problems and address stakeholders' growing environmental concerns, firms have launched recycling programs as one specific corporate social responsibility initiative. While past studies examine recycling programs from a technical perspective, very little research investigates the marketing benefits of such programs. This study draws on signaling theory to develop hypotheses about how firms can strategically design and market a recycling program to trigger positive consumer reactions. Using hierarchical linear modeling of survey data on mobile phone recycling programs across multiple brands, it finds that multiple strategic options of a recycling program (i.e., a product buyback program, product recycling convenience, and packaging recycling) differentially influence consumers' brand attitudes, which consequently affect brand loyalty. Furthermore, an analysis of contingency factors (i.e., brand switching risk, public self-consciousness) suggests that a product recycling program affects brand attitudes only when the brand switching risk is low, and that packaging recycling affects brand attitudes more for consumers with higher public self-consciousness. [Display omitted] • Recycling measures, as CSR types, improve consumers' brand attitudes and loyalty. • Packaging and product recycling measures influence consumer attitudes differently. • Packaging recycling is more effective in improving consumer attitudes. • Packaging recycling is more effective for publicly self-conscious consumers. • Product recycling measures are effective only if brand switching risk is low. [ABSTRACT FROM AUTHOR]

Developing a high-efficiency visible light photocatalyst is always a research hotspot in photocatalytic field. In this study, a novel Z-scheme photocatalyst WO 3 /g-C 3 N 4 with high efficient visible light photocatalytic activity was prepared via ball milling and heat treatment methods. The photocatalyst was characterized by X-ray powder diffraction (XRD), UV–vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron spin resonance (ESR), and photoluminescence (PL). The photocatalytic activity was evaluated by degradation of methylene blue (MB) and fuchsin (BF) under visible light illumination. The results showed that composite WO 3 /g-C 3 N 4 exhibits a much higher photocatalytic activity than a single g-C 3 N 4 . The rate constants of photocatalytic degradation of MB and BF for WO 3 (5.0 wt.%)/g-C 3 N 4 are 4.77 times and 3.84 times that of pure g-C 3 N 4 . The characterization results by physical and chemical methods demonstrated that composite WO 3 /g-C 3 N 4 is a typical Z-scheme photocatalyst. The enhancement of the photocatalytic activity may be attributed to the formation of the Z-scheme system between g-C 3 N 4 and WO 3 , which could result in the photoexcited electrons of g-C 3 N 4 and photoexcited holes of WO 3 participating in oxidation and reduction reactions, respectively. [ABSTRACT FROM AUTHOR]

A direct Z-scheme photocatalyst Bi 2 O 3 /g-C 3 N 4 was prepared by ball milling and heat treatment methods. The photocatalyst was characterized by X-ray powder diffraction (XRD), UV–vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface areas, photoluminescence technique (PL), and electron spin resonance (ESR) technology. The photocatalytic activity was evaluated by degradation of methylene blue (MB) and rhodamine B (RhB). The results showed that Bi 2 O 3 /g-C 3 N 4 exhibited a much higher photocatalytic activity than pure g-C 3 N 4 under visible light illumination. The rate constants of MB and RhB degradation for Bi 2 O 3 (1.0 wt.%)/g-C 3 N 4 are about 3.4 and 5 times that of pure g-C 3 N 4 , respectively. The migration of photogenerated carriers adopts a Z-scheme mechanism. The photoexcited electrons in the CB of Bi 2 O 3 and photogenerated holes in the VB of g-C 3 N 4 are quickly combined, so the photoexcited electrons in the CB of g-C 3 N 4 and holes in the VB of Bi 2 O 3 participate in reduction and oxidation reactions, respectively. O 2 − , OH and h + are the major reactive species for the Bi 2 O 3 /g-C 3 N 4 photocatalytic system. [ABSTRACT FROM AUTHOR]

Highlights: [•] g-C3N4-WO3 photocatalysts with different main parts of C3N4 or WO3 were prepared. [•] The band–band transfer for g-C3N4/WO3 and the Z-scheme for WO3/g-C3N4 were proposed. [•] The activity of g-C3N4/WO3 is not obviously increased compared with pure WO3. [•] The activity of WO3/g-C3N4 is increased greatly compared with pure g-C3N4. [ABSTRACT FROM AUTHOR]

Highlights: [•] A highly active Bi2O3/NaNbO3 photocatalyst was prepared by a facile ball milling. [•] The results revealed that Bi2O3/NaNbO3 is characteristic of Z-scheme photocatalyst. [•] The rate constant of RhB for Bi2O3/NaNbO3 is 6.3 times that of pure NaNbO3. [•] The e− in the CB of Bi2O3 and h+ in the VB of NaNbO3 are quickly combined. [•] The e− in the CB of NaNbO3 and h+ in the VB of Bi2O3 produce •O2 − and •OH, respectively. [ABSTRACT FROM AUTHOR]

Highlights: [•] h-BN/ZnO composite samples were prepared by ball milling process. [•] The photocatalytic activity and stability of ZnO could be substantially improved for cationic dyes’ degradation by coupling with h-BN. [•] The role of h-BN has been discussed to serve as holes-transfer promoter and attractive sites for cationic dyes’ adsorption. [ABSTRACT FROM AUTHOR]

Abstract: High activity hexagonal-BN (h-BN)/TiO2 composite photocatalysts were prepared by ball milling method. The structural and optical properties of the samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (DRS), and fluorescence emission spectra. The effect of the loading amount of h-BN and the ball milling time on the photocatalytic degradation of Rhodamine B (RhB) and methylene blue (MB) was investigated. The results indicated that the photocatalytic activity of TiO2 could be improved substantially by coupling with a proper amount of milled h-BN. The optimal loading amount of h-BN was found to be 0.5wt% and the milling time was 30min. Under this condition, the photocatalytic removal efficiencies of TiO2 for RhB and MB could be increased as high as 15 and 8 times. The role of the milling process and the mechanism for the enhancements was finally discussed in terms of creation of negatively charged h-BN surface and promotion the separation of photoinduced holes, respectively. [Copyright &y& Elsevier]

Interfacial charge transfer efficiency and electronic states of active sites are two essential issues to restrict catalytic activity of electrocatalysts for oxygen evolution reaction (OER). In this work, we show that although Au is recognized to be inert towards OER, the catalytic activity of Fe 3 O 4 catalyst for OER was highly boosted by coupling Fe 3 O 4 with Au to address these two issues. Here, Au nanoparticles were attached to hierarchical Fe 3 O 4 microsphere through electrochemical deposition, a mild and rapid approach that can be accomplished within 3 min and requires no sophisticated equipment. With the coupling of Au, interfacial charge transfer resistance of Fe 3 O 4 declined remarkably. On the other hand, oxidability of Fe sites and electron accepting capability of Au sites was elevated due to strong interaction between Au and Fe 3 O 4. Owing to these two merits induced by Au, Fe 3 O 4 exhibited enhanced catalytic activity for OER. The potential of Fe 3 O 4 to obtain 10 mA/cm2 decreased by 640 mV, the current density was amplified up to 2.5 fold at the potential of 2 V (vs SCE), and the Tafel slop was reduced by 146 mV/dec. This work shows that the catalytic activity of an earth-abundant electrocatalyst (Fe 3 O 4) for OER reaction was boosted by coupling it with OER-inert Au. It is found that the coupling of Au not only facilitated charge transfer efficiency of the catalyst, but elevated the oxidability of Fe sites and electron accepting capability of Au sites. Thereby, when coupled with Au, Fe 3 O 4 exhibited enhanced current density, reduced overpotential, and smaller Tafel slop. [Display omitted] • Enhance catalytic activity of Fe 3 O 4 for OER reaction via coupling of OER-inert Au. • Effectively promoted interfacial charge transfer with the decoration of Au. • Modify the state of Fe sites and Au sites by strong interaction of Au with Fe 3 O 4. • An easy-to-handle and rapid way to couple Au with hierarchical Fe 3 O 4 microspheres. [ABSTRACT FROM AUTHOR]

With the dramatic increase in the application of modern office equipment, such as laser printers and photocopiers, large amounts of waste toner powder are used and discarded, ending up in landfills around the world. As waste toner powder contains hazardous compounds that can seriously endanger both the environment and human health, it is urgent to deal with waste toner powder and convert it into high value-added products. In this work, we report, for the first time, visible-light-driven hydrogen production with waste toner activated by cheap Ni species (waste toner@Ni-species) as the photocatalyst. The Ni species adhered to the waste toner through in situ photoreduction, without sophisticated equipment. It is found that the Ni species were composed of metallic Ni and oxidized Ni, which worked in synergy to remarkably enhance the photocatalytic activity of the waste toner. Activated by the Ni species, the hydrogen evolution rate of the waste toner was accelerated by up to 62 times, and the apparent quantum efficiencies (AQEs) of the waste toner were boosted by up to 64 times. In addition, the waste toner@Ni-species exhibited a higher charge separation efficiency, faster interfacial charge transfer rate and ∼200 mV lower barrier for proton reduction than those of the pristine waste toner. In addition to these merits, the waste toner@Ni-species could be separated conveniently from the aqueous system using magnetic attraction, as the saturation magnetization and residual magnetism of the waste toner were improved with the assembly of the Ni species. The approach shown here indicates a simple and promising way to deal with waste toner by converting it to a cost-effective photocatalyst for producing clean energy. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is considered as a promising approach to storing renewable electricity in the form of hydrogen fuel. In this work, we report the design and electrocatalytic properties of chiral CuO@Ni with three dimensional (3D) continuous macroporous framework. With the chiral CuO@Ni as anode, the OER overpotential required to achieve the current density of 10 mA/cm2 was as low as 110 mV in 0.1 M KOH electrolyte, and the hydrogen production rate of water splitting reaction could reach 1070 nL/s. Moreover, the OER overpotential could be regulated easily by controlling the deposition time of chiral CuO layer on Ni. The high catalytic activity of chiral CuO@Ni for water splitting is closely associated with the Chiral-induced spin selectivity ( CISS ) effect, the large reactive area provided by its 3D macroporous structure, and the effective cooperation between chiral CuO and Ni foam that facilitated the transportation of spin aligned electrons from chiral CuO layer to Ni. The results shown in this work indicate a simple and promising strategy to improve the electrocatalytic activity of other chiral earth-abundant catalysts for water splitting. This work shows the design and properties of chiral CuO@Ni with three dimensional continuous macroporous framework. The chiral CuO@Ni exhibited lower OER overpotential and larger current density than many CuO-based catalysts. Its high catalytic activity for water splitting reaction is attributed to the CISS effect of chiral CuO, the large reactive area of its 3D porous structure, and the synergistic interaction between the chiral CuO and the Ni foam. Image 1 • Chiral CuO@Ni with three dimensional continuous macroporous framework. • Low OER overpotential (110 mV) to achieve 10 mA/cm2 current density. • Easy and effective way to enhance the activity of chiral earth-abundant catalyst. [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting is a promising approach to generating hydrogen from water. In order to enhance water splitting efficiency, it is essential to promote gas revolution from catalysts surface, reduce the over-potential of oxygen evolution (OER), and inhibit the production of the hydrogen peroxide by-product. To realize them, in this work, we take a cue from nature to promote water splitting activity of hollow porous Fe 3 O 4 microspheres (M−Fe 3 O 4) with the aids of hemoglobin. Hemoglobin monolayer was self-assembled on the surface of M−Fe 3 O 4 catalysts. It transported newly-generated oxygen molecules away from catalysts surface and exhibited chiral-induced spin selectivity ( CISS ) effect during OER reaction. Owing to the "helping hand" of hemoglobin, the OER onset potential of hollow porous Fe 3 O 4 microspheres reduced by 100 mV and the current density was enhanced 2 folds. The results indicate a new strategy for designing earth-abundant catalysts which combine the merits of oxygen transferring and CISS effect for electrocatalytic water splitting. Image 1 • Self-assembling hemoglobin monolayer on the surface of hollow Fe 3 O 4 microspheres. • Timely moving newly-generated oxygen molecules away from catalysts by HB layer. • Suppressing H 2 O 2 production by HB induced chiral-induced spin selectivity effect. [ABSTRACT FROM AUTHOR]

Interfacial charge separation is an essential issue to restrict catalytic activity of photocatalysts. In this work, we report a promising and easy-to-handle strategy to modulate the activity of a C 60 -based photocatalyst (C 60 @Pt) for visible-light-driven hydrogen evolution reaction (HER) with the coupling of magnetic substance that had weak ferromagnetism (Fe 3 O 4 microbeads as an instance). It is found that Fe 3 O 4 microbeads played a pivotal role in boosting photocatalytic activity and apparent quantum efficiency of C 60 @Pt for visible-light-driven HER, as the weak local magnetic field it induced around C 60 @Pt contributed to facilitating the separation of photo electrons from electron-donor in reaction system. This work shows a promising strategy to enhance photocatalytic activity of C 60 -based photocatalyst (C 60 @Pt as an instance) for visible-light-driven hydrogen evolution by coupling it with magnetic substance Fe 3 O 4 microbeads that had weak ferromagnetism. It is found that the Fe 3 O 4 microbeads played a pivotal role in enhancing photocatalytic activity of C 60 @Pt as the weak local magnetic field it induced around C 60 @Pt contributed to promoting the separation of photo-excited electrons from electron-donor. This strategy effectively boosted hydrogen evolution rate and AQE of C 60 @Pt. [Display omitted] • Modulate activity of C 60 -based photocatalyst via connecting weak magnetic substance. • Promote separation of photo-excited electrons by inducing weak local magnetic field. • AQE was boosted up to 2.5 times with the coupling of weak magnetic substance. • Hydrogen evolution improved up to 3.7 times when connecting weak magnetic substance. • Remarkably improve HER photocatalytic robustness of C 60 -based photocatalyst. [ABSTRACT FROM AUTHOR]

Herein, a ZnIn 2 S 4 -decorated attapulgite photocatalyst (ZnIn 2 S 4 /ATP) was successfully synthesized by a facile oil bath heating method. It shows superior reduction efficiency for the removal of Cr(Ⅵ). The improved photocatalytic performance is primarily attributed to the intercalation effect of ZnIn 2 S 4 and attapulgite (ATP), enhanced separation efficiency of photogenerated electron-hole pairs, and improved transport efficiency of photogenerated carriers. Moreover, insight into the photocatalytic mechanism demonstrates that •O 2 − and e− are the major active species in the photocatalytic reduction of Cr(VI) over ZnIn 2 S 4 /ATP. This work serves as a reference for integrating natural clay with semiconductors for photocatalytic wastewater treatment. [Display omitted] • Efficient visible-light-driven ZnIn 2 S 4 /attapulgite photocatalyst was fabricated. • ZnIn 2 S 4 /attapulgite shows superior photocatalytic efficiency for the removal of Cr(Ⅵ). • The improved photocatalytic performance is attributed to the high dispersion of ZnIn 2 S 4 on attapulgite. • O 2 − and e− are the active species for Cr(Ⅵ) reduction. [ABSTRACT FROM AUTHOR]

A composite photocatalyst (Bi3.84W0.16O6.24–Bi2WO6) containing Bi, W and O elements was prepared by a facile hydrothermal method. Various characterization methods such as X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy, scanning electron microscopy and transmission electron microscopy were employed to investigate the structure and optical properties. The activities of the samples were evaluated by the photocatalytic degradation of methylene blue under visible light irradiation. The results showed that when the pH of the precursor solution is 12.3, and a hydrothermal treatment at 140 °C for 20 h was used, the prepared sample shows the mixed phases of Bi3.84W0.16O6.24 and Bi2WO6. The Bi3.84W0.16O6.24–Bi2WO6 composite exhibited an enhanced photocatalytic activity compared with single Bi2WO6 or Bi3.84W0.16O6.24. The rate constant of Bi3.84W0.16O6.24–Bi2WO6 is about 5 times that of Bi2WO6. It is proposed that the increased photocatalytic activity may be attributed to the formation of a heterojunction between Bi3.84W0.16O6.24 and Bi2WO6, which suppresses the recombination of photoexcited electron–hole pairs. [ABSTRACT FROM AUTHOR]

Highlights: [•] Bi(OH)CrO4 excited by visible-light was synthesized by the hydrothermal method. [•] Only orthorhombic crystal was observed for preparation of Bi(OH)CrO4 at 180°C for 24h. [•] The Bi(OH)CrO4 prepared at 180°C for 24h has the most excellent photocatalytic activity. [•] OH and h+ are main reactive species of Bi(OH)CrO4 for MB decolorization. [ABSTRACT FROM AUTHOR]

• An interfacial Mo-S bond-bridged hierarchical S-scheme heterostructure is reported. • The Mo-S bonds can reinforce the separation and migration of photoinduced carriers. • The hierarchical heterostructure can benefit the CO 2 adsorption and activation. Developing highly-selective and efficient photocatalysts for converting CO 2 into carbon-based fuels by solar energy is desirable, whereas it is still a severe challenge. Herein, we present a unique interfacial Mo-S bond-bridged hierarchical S-scheme heterostructured photocatalysts, prepared by in-situ loading ZnIn 2 S 4 nanoflakes (ZIS-NFs) on the Bi 2 MoO 6 porous micro-spheres (BMO-PMs) assembled from numerous nanosheets. The interfacial Mo-S bonds can reinforce the separation and migration of photoinduced charge carriers via the S-scheme mechanism in the BMO@ZIS heterostructure. Besides, its hierarchical heterostructure can improve the visible-light response ability, and afford plenty of active sites so as to benefit the CO 2 adsorption and activation. Specifically, the combined results of experiment and density functional theory (DFT) calculations indicate that the fine heterostructure can not only convert the endoergic rate-determining step of bare ZIS (namely, CO 2 * hydrogenation to form COOH*) to an exoergic reaction process and lower the overall activation energy barrier, but also boost the desorption of CO* from the ZIS surface. As a result, in existence of H 2 O vapor without any sacrificial agents, the optimum photocatalyst (BMO@ZIS-0.4) manifests the outstanding CO 2 photoreduction activity, with a CO yield and selectivity of 23.11 μmol g−1h−1 and 93.1 %, respectively, higher than those of the most reported photocatalysts. This work offers an in-depth insight for fabricating the interfacial chemical bond-modulated hierarchical S-scheme heterostructure with a remarkable performance of CO 2 conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flower-like Cu-doped In 2 S 3 was constructed through a one-step hydrothermal method. • Cu-doping enhanced visible-light response and BET surface area of In 2 S 3. • Cu-doped In 2 S 3 exhibited excellent adsorption and catalytic degradation activity of Rhodamine B. • Superoxide ion radical was the main active substance in initiating the degradation of Rhodamine B. In 2 S 3 materials doped with different concentrations of copper ions (Cu-In 2 S 3) were designed and synthesized, which successfully improves the response to visible light, separation of carriers, and adsorption for rhodamine B of In 2 S 3. Cu-doping improves the photocatalytic activity of In 2 S 3 for dye removal. In 2 S 3 doped with 0.3% Cu2+ exhibits the highest photocatalytic activity for the degradation of rhodamine B. In addition, it shows high photocatalytic stability. The photocatalytic active species capture experiments show that the superoxide radical was the main active substance for the photocatalytic degradation of rhodamine B over 0.3% Cu-In 2 S 3. This study provides a valuable reference for the construction of In 2 S 3 -based photocatalytic materials. [ABSTRACT FROM AUTHOR]

• In 2 O 3 /CuBi 2 O 4 heterojunction photocathodes are in situ formed. • The In 2 O 3 /CuBi 2 O 4 photocathode exhibits a significantly enhanced photocurrent. • Charge transfer in the In 2 O 3 /CuBi 2 O 4 heterojunction is much better than the pure CuBi 2 O 4. As a promising material for solar water splitting, p-type CuBi 2 O 4 semiconductor has attracted much attention due to its unique advantages. However, the photoelectrochemical (PEC) activity of the CuBi 2 O 4 is far from satisfactory due to its less efficient carrier transport. In this study, a doped method is used to prepare a layer of indium oxide on the surface of CuBi 2 O 4 , that is, a new In 2 O 3 /CuBi 2 O 4 heterojunction thin film is prepared. We compare the performance of pure CuBi 2 O 4 and In 2 O 3 /CuBi 2 O 4 through electrochemical testing and several physical characterizations. The final experimental results show that indium oxide can improve the PEC properties of CuBi 2 O 4 by reducing the recombination of electrons and holes and improve the charge transport. [ABSTRACT FROM AUTHOR]

Graphical abstract One-step nitridation process of Ta foils with and without the assistance of CO 2 under ammonia flow. Abstract Metal nitrides are widely studied due to their outstanding physical properties, including high hardness, high thermal and chemical stability, low electrical resistivity etc. Generally, metal nitrides can be obtained from the direct reaction of metal and ammonia/nitrogen. However, some of the metal nitrides, such as Ta 3 N 5 , cannot be synthesized by direct nitridation of metals. To achieve Ta 3 N 5 , high-oxidation-state Ta precursors like Ta 2 O 5 , NaTaO 3 , TaS 3 , K 6 Ta 10.8 O 30 , Ta(N(CH 3) 2) 5 and TaCl 5 have to be employed, which is a time-consuming and laborious process with the possibility of introducing undesirable impurities. Here taking Ta 3 N 5 as an example, a facile carbonate-assisted one-step nitridation method is proposed, which enables the direct synthesis of high-oxidation-state metal nitride films from metal precursors under ammonia flow. The mechanism of the nitridation process has been studied, which carbon dioxide released from carbonates decomposition reacts with metallic Ta and assists the one-step conversion of metallic Ta to Ta 3 N 5. The as-prepared Ta 3 N 5 film, after modified with NiFe layered double hydroxide, exhibits promising water splitting performance and stability. This method avoids the preoxidation process of metal precursors in high-oxidation-state metal nitride synthesis, and may facilitate the direct fabrication of other important metal nitrides besides Ta 3 N 5. [ABSTRACT FROM AUTHOR]

[Display omitted] • Au/ZnIn 2 S 4 was constructed through a single photochemical method. • Au/ZnIn 2 S 4 exhibited excellent visible-light-driven catalytic debromination activity of BDE-47. • Electron transfer was the main step in initiating the dehalogenation of BDE-47. • SPR of Au and its affinity with BDE-47 co-improved the debromination of BDE-47 by ZnIn 2 S 4. 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) is a highly toxic organic pollutant. Owing to the high structural stability, BDE-47 is difficult to be naturally decomposed. In this study, Au nanoparticles decorated flower-like ZnIn 2 S 4 microspheres were successfully fabricated and applied for the rapid removal of BDE-47 driven by visible-light irradiation. It was revealed that 3 wt% Au-loaded ZnIn 2 S 4 (Au/ZnIn 2 S 4) has the highest removal rate for BDE-47 (0.90118 h−1). A study of the reaction path and mechanism shows that the bromine adjacent to the oxygen atom in BDE-47 tends to be removed via electron transfer. This is attributed to the band-gap excitation of ZnIn 2 S 4 , the surface plasmon resonance effect of the Au nanoparticles, and the Schottky junctions between them. Furthermore, density functional theory calculations show that the strong affinity between Au0 and the bromine atom adjacent to the oxygen atom in BDE-47 can lengthen the carbon–bromine bond and further weaken the bond upon the accumulation of electrons. This may be the main reason for the rapid debromination of BDE-47. This study provides a new perspective on the photocatalytic removal of moderately brominated polybrominated diphenyl ethers. [ABSTRACT FROM AUTHOR]

Understanding the photocatalytic reductive dehalogenation mechanism of halogenated aromatic pollutants is of great research value. However, the proton source in the photocatalytic dehalogenation process of representative halogenated aromatic pollutants by TiO 2 is not clear. In this study, the TiO 2 surface was modified by hydrochloric acid, sodium hydroxide, and sodium fluoride to obtain TiO 2 samples with different hydroxyl groups. It was found that the hydroxyl groups on the surface of TiO 2 affects the sequence of proton and electron transfer in dehalogenation. The abundance of hydroxyl groups on the surface of TiO 2 can accelerate the reductive dehalogenation process of representative halogenated aromatic pollutants. The kinetic solvent isotope effect was used to study the proton-coupled electron transfer process in the reaction. It shows that the enriching of protons on TiO 2 bridging oxygen (bridging hydroxyl groups) is conducive to the rapid step of protonation of the reactant, and subsequent proton and electron transfer. On the contrary, the bridging hydroxyl groups can be removed by reacting with strongly basic sodium hydroxide and sodium ions can occupy the bridging oxygen. The substitution of bridging oxygen by fluorine ions can also lead to the destruction of bridge hydroxyl groups. Significantly, the absence of bridging hydroxyl groups on titanium dioxide will lead to the dehalogenation of representative halogenated aromatic pollutants initiated by electron transfer. This study is helpful to understand dehalogenation reaction paths catalyzed by TiO 2. [Display omitted] • Regulation of surface hydroxyl groups on TiO 2 by acid, base, and NaF modification. • Debromination induced by proton transfer on TiO 2 with abundant bridging hydroxyls. • Debromination initiated by electron transfer on TiO 2 lacking bridging hydroxyls. [ABSTRACT FROM AUTHOR]

• An easy-to-handle way to boost charge transfer for α-Fe 2 O 3 rods by chiral monolayer. • Photocurrent density amplified up to 4 folds with the coupling of chiral monolayer. • Free charge carrier density enhanced by 61% with the coupling of chiral monolayer. • Charge transfer resistance reduced remarkably with the coupling of chiral monolayer. α-Fe 2 O 3 is an attractive semiconductor for solar energy conversion because of its narrow band gap, robustness and low cost, while its solar energy conversion efficiency is restricted due to poor electrical conductivity and high charge transfer resistance. In this work, we show an easy-to-handle way to deal with the drawback by coupling α-Fe 2 O 3 rods with chiral monolayer to facilitate charge transportation. It is found that with the coupling of chiral monolayer, charge migration resistance of α-Fe 2 O 3 was remarkably reduced, visible-light-driven photocurrent density was amplified up to 4 folds, and the free charge carrier density was enhanced by 61%. These enhancement could be related to the Chiral Induced Spin Selectivity effect of chiral monolayer on spin alignment of charge carriers. [ABSTRACT FROM AUTHOR]

Based on the difference of coordination structure between cubic and hexagonal phase, a facie method to control the growth of hexagonal NaYF 4 and NaYF 4 : Yb, Er powder was designed. By selecting the proper reaction precursor, adjusting the pH value and directly changing the F−/Y3+ molar ratio, the anion-cation ratio in the reaction system can reach high to meet the requirements of the hexagonal phase with high coordination ions, and finally the hexagonal powder can be directly obtained. In the whole process, neither any organic additives, nor high temperature and high pressure were involved, which is an environmentally friendly technology. It is found that the as prepared powder can emit red upconversion luminescence with a high R/G ratio, which is significantly different from the light emitted by the usually synthesized hexagonal phase. [Display omitted] • The hexagonal phase NaYF 4 and NaYF 4 : Yb, Er was synthesized by a green method. • The synthesis is at room temperature and ambient pressure without organic additives. • The product can emit red light with a high R/G ratio. • The growth mechanism based on the difference of coordination structures was proposed. Based on the structure difference between cubic and hexagonal phases, a facile method was designed for the synthesis of pure hexagonal phase β -NaYF 4 and β -NaYF 4 : Yb, Er powder at room temperature and ambient pressure. In the whole process, neither any organic additives, nor high temperature and high pressure were involved that indicated an environmentally friendly technology. The optimal synthesis conditions for hexagonal phase at room temperature is the pH value between 5.0 and 6.5, the amorphous Y (OH) 3 as Y precursor and the F−/Y3+ molar ratio equal to 6:1. A possible preparation mechanism based on the difference between the coordination structure of the hexagonal and the cubic phases was also proposed. It is found that the as prepared powder of the hexagonal phase can emit red upconversion luminescence with a high R/G ratio, which is significantly different from the light emitted by the usually synthesized hexagonal phase. This method can also provide a new perspective for studying the sustainable synthesis of rare earth compounds. [ABSTRACT FROM AUTHOR]

Ce2S3 photocatalysts were synthesized by a co-precipitation method using cerium nitrate and thioacetamide as raw materials. The samples were characterized by X-ray powder diffraction analysis, UV–visible diffuse reflectance spectroscopy, scanning electron microscopy, and differential thermal analysis. Photocatalytic reduction of nitrobenzene (NB) under UV or visible light illumination was used to evaluate the photocatalytic activity of the Ce2S3 samples. The result indicated that the sample prepared at 300°C for 12h exhibited the highest activity. For 140mL 8.13×10−4 mol/L of NB in methanol solvent, after illumination for 5h, about 43.9% and 34.7% of NB were reduced to aniline over the sample under UV and visible light irradiation, respectively. The effects of the catalyst amount, illumination time, and sorts of solvent on the photocatalytic performance were investigated specifically. The reduction process of NB over Ce2S3 was finally discussed. [ABSTRACT FROM AUTHOR]

In the paper, the effects of polyvinylpyrrolidone (PVP) concentration and chemical wet etching on morphologies and phase composition of CuSbS2 particles synthesized by microwave irradiation method were investigated. The phase structure, morphologies, and optical and photocatalytic properties were analyzed by using characterization techniques. The results showed that the morphology of as-prepared particles was spherical and the shape of particles etched in Na2S solution was tetragonal rod-like structure. The optical band gap of the particles with 1.5 g PVP after chemical etching was about 1.41 eV. The photocatalytic performance of CuSbS2 could be significantly improved after Na2S chemical etching. The amounts of PVP had an obvious influence on specific surface area of as-synthesized CuSbS2 particles. The CuSbS2 particles with 1.5 g PVP had the best photocatalytic performance after chemical etching treatment, and the C/C0 value reached 0.36. [ABSTRACT FROM AUTHOR]