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Aurivillius‐type compounds ((Bi2O2)2+(An–1BnO3n+1)2−) with alternately stacked layers of bismuth oxide (Bi2O2)2+ and perovskite (An−1BnO3n+1)2− are promising photocatalysts for overall water splitting due to their suitable band structures and adjustable layered characteristics. However, the self‐reduction of Bi3+ at the top (Bi2O2)2+ layers induced by photogenerated electrons during photocatalytic processes causes inactivation of the compounds as photocatalysts. Here, using Bi3TiNbO9 as a model photocatalyst, its surface termination is modulated by acid etching, which well suppresses the self‐corrosion phenomenon. A combination of comprehensive experimental investigations together with theoretical calculations reveals the transition of the material surface from the self‐reduction‐sensitive (Bi2O2)2+ layer to the robust (BiTiNbO7)2− perovskite layer, enabling effective electron transfer through surface trapping and effective hole transfer through surface electric field, and also efficient transfer of the electrons to the cocatalyst for greatly enhanced photocatalytic overall water splitting. Moreover, this facile modification strategy can be readily extended to other Aurivillius compounds (e.g., SrBi2Nb2O9, Bi4Ti3O12, and SrBi4Ti4O15) and therefore justify its usefulness in rationally tailoring surface structures of layered photocatalysts for high photocatalytic overall water‐splitting activity and stability. [ABSTRACT FROM AUTHOR]

Solar‐to‐hydrogen conversion is a sustainable way of producing renewable fuels, yet the efficiency is limited by the poor photo‐induced charge‐carrier separation on electrode surface. Developing active and stable hydrogen evolution photocatalysts is challenging and entails intelligent material structure design and tailoring. Here, a novel water dispersible supramolecular metal organic framework (SMOF) is employed as a general and high‐performance platform to encapsulate CdS quantum dots (QDs) for achieving highly improved solar‐induced H2‐production activity. Particularly, the CdS QDs@SMOF heterostructure exhibits an excellent H2 generation activity of 49.4 µmol h−1 (TOF = 47.0/h), exceeding those of most reported heterogeneous metal organic frameworks‐based photocatalytic systems. Advanced characterizations disclose that the strong electrostatic interaction and light‐induced charge transfer between SMOF and CdS QDs, combined with the high surface area, water dispersible nature, and abundant reactive centers synergistically contribute to this distinguished photocatalytic performance. The work not only demonstrates the water dispersible SMOF can serve as a versatile and effective platform supporting semiconductor to boost the photocatalytic H2‐production performance without co‐catalysts, but also paves avenues to the design and synthesis of SMOF‐based heterostructures for general catalysis applications. [ABSTRACT FROM AUTHOR]

Abstract: Although NiCoP has attracted much attention in the field of electrocatalysis, the study of its photocatalytic activity and mechanism have been somewhat limited. NiCoP/g‐C3N4, synthesized by simple one‐pot method, is a highly efficient photocatalyst for hydrogen production from water. NiCoP/g‐C3N4 exhibits a hydrogen evolution rate of 1643 μmol h−1 g−1, which is 21 times higher than that of bare g‐C3N4. The excellent performance is due to a combination of improved separation efficiency and effective charge transfer efficiency. The photogenerated charge behavior is characterized by the surface photovoltage (SPV), transient photovoltage (TPV), and photoluminescence spectroscopy. The photogenerated charge transport is investigated by electrochemical impedance spectroscopy and polarization curve. Moreover, the effective charge transfer efficiency was measured according to the mimetic apparent quantum yield. SPV and TPV measurements, whereby 10 vol % of a triethanolamine–water mixture was added into the testing system, were taken to simulate the real atmosphere for photocatalytic reaction, which can give rise to the photogenerated charge transfer process. A possible photocatalytic mechanism was also proposed. This study may provide an efficient theoretical basis to design transition metal phosphide cocatalyst‐modified photocatalysts. [ABSTRACT FROM AUTHOR]

Bimetallic materials hold promise for improving catalyst activity, yet little is known about the photocatalytic mechanism that these systems undergo during photocatalytic reaction that lead to efficient catalyst. Herein, we synthesized g-C3N4 combined with PtNi x, which shows much higher photocatalytic activity than that of pure g-C3N4 and achieves the highest H2 evolution rate of 8456 μmol h−1 g−1 for 2.5 % PtNi x/g-C3N4. The excellent photocatalytic activity resulted from the enhanced charge-separation efficiency compared to the pristine g-C3N4, which was proved by surface photovoltage, photoluminescence, and transient photovoltage spectra. Electrochemical impedance spectroscopy in the dark further confirms the ability of charge transfer of 2.5 % PtNi x/g-C3N4 is superior to that of pure g-C3N4. This effective separation efficiency gives rise to the observed excellent photocatalytic activity. This study not only provides us with an efficient catalyst for water splitting, but opens new avenues for designing and developing platinum-based photocatalysts. [ABSTRACT FROM AUTHOR]

A facile synthetic route is presented that produces a porous Ga-In bimetallic oxide nanophotocatalyst with atomically thin pore walls. The material has an unprecedented electronic structure arising from its ultrathin walls. The bottom of the conduction band and the top of the valence band of the material are distributed on two opposite surfaces separated with a small electrostatic potential difference. This not only shortens the distance by which the photogenerated charges travel from the sites where they are generated to the sites where they catalyze the reactions, but also facilitates charge separations in the material. The porous structure within the walls results in a large density of exposed surface reactive/catalytic sites. Because of these optimized electronic and surface structures, the material exhibits superior photocatalytic activity toward the hydrogen evolution reaction (HER). [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) BiVO4/Bi2WO6 composite microspheres with enhanced visible-light (λ ＞ 420 nm) photodegradation activity of methylene blue (MB) were synthesized by a simple, one-pot, template-free solvothermal method. A mixture of ethylene glycol (EG) and H2O (volume ratio of EG-H2O was 1 : 1) was used as the solvent. To investigate the relationship between structure and photocatalytic performance, the as-synthesized samples were characterized by XRD, FESEM, HRTEM, UV-vis DRS, SPS and TPV. Structural characterizations indicated that the composite nanostructure mainly consisted of two single-crystal phases, which were BiVO4 and Bi2WO6. In addition, a possible growth mechanism of this microsphere composite and the separation process of photoinduced charge carriers in the heterojunction are discussed. [ABSTRACT FROM AUTHOR]

CuS/Zn0.8Cd0.2S composites have been successfully prepared by simple hydrothermal and cation exchange method. The Cu species loaded on Zn0.8Cd0.2S, together with the intimate contact formed between CuS and Zn0.8Cd0.2S, was clearly demonstrated with X-ray photoelectron spectroscopy and transmission electron microscopy. The optimized CuS/Zn0.8Cd0.2S photocatalyst has a high H2 evolution rate of 2792 μmol g−1 h−1 at CuS content of 3 wt% and the apparent quantum efficiency of 36.7% at 420 nm. The photophysical mechanism of the photocatalytic activity was investigated with the help of surface photovoltage spectroscopy (SPS) and transient photovoltage (TPV) techniques. The results revealed that photogenerated charge separation efficiency in Zn0.8Cd0.2S was enhanced and the photogenerated electrons were trapped by the loaded CuS, which benefits photo-reduction. Those were the reasons for significant enhancement in the photocatalytic H2 evolution from water splitting. [ABSTRACT FROM AUTHOR]

Abstract: TiO2(B) was prepared by a facile green solvothermal method and further characterized by the powder X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), raman spectroscopy and nitrogen sorption analysis, and it has been found that the as-synthesized sample possesses a unique crystallites/nanopores structure and has a very large surface area (484m2 g−1). Surprisingly, it exhibits the very high photocatalytic activity and good stability for the decomposition of methyl orange (MO) compared to that of P25. [ABSTRACT FROM AUTHOR]

A series of nano-spindly BiVO 4 and Ag-BiVO 4 were synthesized by a simple solvothermal method. X-ray photoelectron spectroscopy (XPS) and high resolution electron microscopy (HRTEM) analysis indicated that the chemical state of the Ag particles was metallic Ag. Their photocatalytic activities were evaluated by the decolorization of rhodamine B (RhB) under visible light irradiation ( λ > 420 nm). The research of photoinduced charge properties of samples studied by surface photovoltage spectroscopy (SPS) and electric field-induced surface photovoltage spectroscopy (FISPS) measurement system and the results indicated that the existence of Ag attained the enhancement of photoinduced charge carriers’ separation. This was thought to be responsible for the higher efficient photocatalytic activity of Ag-BiVO 4 in the degradation of RhB. [ABSTRACT FROM AUTHOR]

Abstract: Different sizes of ZnWO4 photocatalysts were synthesized by a hydrothermal method. The as-prepared sample shows highly efficient photocatalytic activity for the degradation of RhB under UV irradiation, which significantly vary with the increase of the hydrothermal temperatures. Surface photovoltage spectrum (SPS), field-induced surface photovoltage spectrum (FI-SPS) and surface photovoltage transient (TPV) techniques are used to investigate the detailed photoinduced charge transfer behavior. Results indicate that the ZnWO4 synthesized at 413K possess the largest BET surface area and the abundant donor surface states which are assumed to inhibit the recombination of the photogenerated electron–hole pairs, and thus a significant enhancement in the reaction rate is observed. [Copyright &y& Elsevier]

[Display omitted] • Nitrogen vacancies were introduced to regulate the microstructure of carbon nitrogen and facilitate co-catalyst loading. • Nitrogen vacancies were beneficial to capture [PtCl6]2- and reduce [PtCl6]2- by photo-generated electrons, hence stabilizing Pt ultra-small clusters. • The interaction between nitrogen vacancies and Pt ultra-small clusters was unveiled by test of field scanning steady state surface photovoltage (fs-SPV). • The interaction between nitrogen vacancies and Pt ultra-small clusters improves the sluggish kinetics of electron transfer, boosting photocatalytic hydrogen production. Tuning the microstructure of the catalyst surface is crucial for the loading of the co-catalyst, especially influencing the electron transfer and the size of the co-catalyst. However, influence of co-catalyst loading, related to the surface structure of the catalysts, is largely ignored. Here in, nitrogen vacancies were introduced to regulate the microstructure of carbon nitrogen and using this amorphous carbon nitride (ACN) with nitrogen vacancies as a substrate to provide atomic anchoring sites as well as electron sink to prevent Pt from further agglomeration. Experimental and theoretical results show that nitrogen vacancies were electron acceptors, which beneficial to reduce [PtCl 6 ]2− by photo-generated electrons and consequently stabilize Pt ultra-small clusters located on the ACN. Furthermore, by combing structure and carrier behaviors, we infer that Pt ultra-small clusters stable location comes from the strong interaction between Pt and nitrogen vacancies. Pt ultra-small clusters improve electron transfer and boost photocatalytic hydrogen production. A delicate design modulates the catalyst microstructure to enhance interaction between the catalyst and the co-catalyst, resulting in a smaller co-catalyst size and provides a mean to create and optimize small size Pt-loaded and highly active photocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surfactant-assisted synthesis of ZnS(C)/BiOBr/GO composite photocatalyst has been prepared successfully for the first time. • The highly dispersed photocatalyst further applied for Rh B, TCH and BB degradation under visible light irradiation. • The highest degradation rate constants for Rh B (0.76750 min−1), TCH (0.05754 min−1) and BB (0.12515 min−1) were achieved. • The energy band structure of ZnS and BiOBr leads to the excellent charge separation efficiency of composites. • The application of surfactant can effectively improve the dispersion and degradation performance of photocatalysts. In this paper, the highly dispersed ZnS(C)/BiOBr/ GO ternary composite was prepared by a two-step hydrothermal method with the help of the surfactant cetyltrimethyl ammonium bromide (CTAB). Its structure and morphology were studied by XRD, SEM, TEM, EDX spectra, UV–VIS absorption spectra, Mott-Schottky curve and Brunau-Emmett-Teller (BET) characterization. The results show that the ZnS(C)/BiOBr/GO ternary photocatalyst with excellent degradation effect and stable specific surface area has been successfully prepared. Orthogonal and photocatalytic experiments showed that the prepared photocatalyst had high photocatalytic performance for the degradation of brilliant blue (BB), Rhodamine B (RhB) and tetracycline hydrochloride (TCH). The degradation rate constants for BB, TCH and RhB were 0.12515, 0.06194 and 0.76750 min−1, respectively. Moreover, the photocatalytic performance of ZnS(C)/BiOBr/GO composite is significantly better than that of the original ZnS(C) and BiOBr. It is worth noting that ZnS(C)/BiOBr/GO ternary composite assisted by CTAB has the best photocatalytic activity, mainly for two reasons. First, the presence of surfactant CTAB significantly reduces the agglomeration of ZnS and enhances the dispersion of ZnS. Second, GO can be used as an electron trapping agent between ZnS and BiOBr to promote carrier separation. Therefore, the synthesis of ternary compounds with appropriate additional surfactants can effectively improve the photocatalytic efficiency of the degradation of organic pollutants. This study is expected to expand the application of surfactants in the preparation of semiconductor photocatalysts. [ABSTRACT FROM AUTHOR]

of two-dimensional structure have been extensively studied for their prospect in the field of photocatalysis research. In this research, an innovative composite of 3D flower-like MoS 2 coated with FeTiO 3 nanoparticles was designed and prepared to solve the problems of water environmental pollution using a simple sol-gel method and hydrothermal method. Surface morphology and microstructure were investigated, which indicates that MoS 2 /FeTiO 3 heterojunction structure was fabricated successfully, compared with the pristine materials, enabled increased Brunauer-Emmett-Teller (BET) surface area, the strengthen of light utilization and more efficient separation efficiency of photoexcited charge in the interfacial electric field. Correspondingly, the MoS 2 /FeTiO 3 photocatalyst exhibits the excellent visible-light-responsive photocatalytic activity for the degradation of tetracycline hydrochloride (TCH), which was 0.02121 min−1 by MoS 2 /FeTiO 3 photocatalyst with the optimized condition. The scavenger tests of reactive oxidation species scavenger (ROSs) demonstrate that the enhanced degradation activity of TCH is ascribed to the existence of the photoexcited hole (h+), superoxide radicals (∙O 2 −) and hydroxyl radicals (∙OH). The results of ROSs and Mott-Schottky (M-S) indicate that band bending is formed for MoS 2 /FeTiO 3 composites with the orientation of the interface electric field form FeTiO 3 to MoS 2 due to the fact that the Fermi level of FeTiO 3 is higher than that of MoS 2 , resulting in the transfer of photoexcited electron from MoS 2 to conduction band (CB) of FeTiO 3 , and the photoexcited holes from FeTiO 3 to valence band (VB) of MoS 2. And the charge transfer process of Ⅱ-type heterostructure is proposed according to the energy band structure of MoS 2 and FeTiO 3 , as well as the results of experiments. Therefore, we believe that our well-designed MoS 2 /FeTiO 3 heterostructure effectively contributes to the progress of photocatalytic degradation and the treatment of water pollution. [Display omitted] • A 3D flower-like MoS 2 /FeTiO 3 heterostructure was prepared via a simple method for the first time. • The heterostructured photocatalyst further applied for TCH degradation under visible light irradiation. • The highest degradation rate constants for TCH (0.02121 min−1) were obtained by MoS 2 /FeTiO 3 photocatalyst. • The energy band structure of MoS 2 and FeTiO 3 leads to the forming of interface electric field at the interface. • The separation efficiency of photoexcited charge can be promoted in the Ⅱ-type heterostructured interface. [ABSTRACT FROM AUTHOR]

In this paper, a series of BiOI/ZnO photocatalysts containing various BiOI contents were prepared by a facile two-step synthetic method. The structure and crystal phase, morphology, surface element analysis, optical property of as-prepared samples are measured by X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV–Vis diffuse reflectance spectrometry (DRS). BiOI/ZnO photocatalytic activities of the prepared photocatalysts were evaluated by photocatalytic degradation of phenol under simulated light irradiation. The phenol degradation rate reached 99.9% within 2 h under simulated solar light irradiation. The probable photocatalytic mechanism of composites photocatalysts is discussed by active species trapping experiments, the surface photovoltage (SPV), the transient photovoltage (TPV) and photoluminescence (PL) measurements. The results manifest that the superior photocatalytic activity of BiOI/ZnO composites is derived from the strong internal electric field between BiOI and ZnO, which is beneficial for the effective separation and transfer of photogenerated charges in ZnO. Moreover, the loading of BiOI on the surface of ZnO inhibited the recombination of photogenerated charge carriers in ZnO, resulting in excellent photocatalytic activity. On the contrary, the effect of an extension of the light absorption range induced by the introduction of BiOI on the phenol degradation activity is not significant. [ABSTRACT FROM AUTHOR]

In this study, Ce-doped ZnO photocatalysts are successfully prepared by using a simple and facile one-pot water bath method. The as-prepared samples are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) diffuse spectroscopy and Brunauer-Emmett-Teller (BET) surface area analysis. It is found that the as-synthesized Ce-doped ZnO possessed hollow porous structure, high surface areas and large pore volumes. The photocatalytic degradation efficiency (99%) of methyl orange (MO) with an optimal molar ratio of 0.3% Ce-doped ZnO is realized. The separation behavior of photogenerated electrons-holes pairs was investigated by surface photovoltage (SPV) and transient photovoltage (TPV) technique. The results illuminate that Ce element in Ce-doped ZnO tremendously promotes the separation of charges and inhibits the recombination of photogenerated charge carriers, corresponding to the excellent photocatalytic performance. [ABSTRACT FROM AUTHOR]

To better understand the behavior of photogenerated charges in the composite photocatalyst interface is beneficial to the designing of effective photocatalyst for photocatalytic reaction. In our work, the separation and transfer process of photogenerated charges in NiO/TiO 2 nanotube arrays (NiO/TiO 2 NTAs) has been studied by surface photovoltage (SPV) spectroscopy and transient photovoltage (TPV) measurement. Through the experimental results analysis, we find that an interfacial electric field is formed at NiO/TiO 2 NTAs interface, which is attributed to the work function difference between NiO and TiO 2 NTAs. The photogenerated holes in TiO 2 can transfer to the NiO layer along the interface electric field under the ultraviolet irradiation. A large amount of photogenerated holes can be separated effectively and then prolonged the holes lifetime to participate in the photocatalytic oxidation reaction. The above results show that the favorable hole-collecting process of NiO in the surface of TiO 2 NTAs is the main factor being responsible for the increase the photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

● LaFeO 3 /In 2 S 3 Z-scheme composite has been prepared successfully for the first time. ● The heterostructured photocatalyst is applied for Rh B, TCH and BB degradation. ● The highest degradation rate was achieved by the prepared photocatalyst. ● The band structure of heterostructure leads to the forming of the Z-scheme route. ● The photoexcited charge in LaFeO 3 /In 2 S 3 transfer in an unobstructed Z-scheme route. [Display omitted] Materials of perovskite-type structure have been widely investigated for their prospect in photocatalysis. In this work, a novel composite material of p-type LaFeO 3 microsphere coated with n-type In 2 S 3 nanoparticles was fabricated to settle the water pollution problems through a mild hydrothermal method. The structure and morphology were studied by XRD, SEM, TEM, EDX mapping and UV–visible absorption spectra. The results indicated that the LaFeO 3 /In 2 S 3 heterostructured photocatalyst was prepared successfully, and show an enhanced BET surface area and visible light absorption. The obtained heterostructured photocatalyst was applied to the photocatalytic degradation of rhodamine B (Rh B), tetracycline (TCH) and brilliant blue (BB). Under optimized conditions, the degradation rate of LaFeO 3 /In 2 S 3 photocatalyst was dozens of times that of the pristine LaFeO 3 and pristine In 2 S 3. Notably, the degradation rate constant for Rh B, TCH and BB was 0.16709, 0.02684 and 0.0175 min−1 over as-prepared LaFeO 3 /In 2 S 3 photocatalyst, respectively. The surface photovoltage (SPV), reactive oxidation species scavenger (ROSs) and work function (WF) tests were applied to investigate the photoexcited charge behavior of LaFeO 3 /In 2 S 3 and the possible mechanism of photocatalytic degradation. The results demonstrate that the band bending is formed at the LaFeO 3 /In 2 S 3 heterostructured interface because the WF of LaFeO 3 is higher that of In 2 S 3 , which leads to the transfer of photoexcited electron from conduction band (CB) of LaFeO 3 to valence band (VB) of In 2 S 3 and the excellent photocatalytic degradation activity of water pollutants. And the Z-scheme charge transfer process was suggested at the LaFeO 3 /In 2 S 3 interface based on the energy band structure of LaFeO 3 and In 2 S 3 and ROSs results. Therefore, we believe that our rationally conceived LaFeO 3 /In 2 S 3 heterostructured photocatalyst advances the development of photocatalytic degradation and environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Spatially adjacent Yin-Yang co-catalyst (CoO x -Mo 2 N) is better than dual spatially separated co-catalysts of CoO x and Mo 2 N. • Each component of Yin-Yang (CoO x - Mo 2 N) has opposite function. • Adjacent spatial configuration, favorable water molecular absorption and two electron reactive path with H 2 O 2 as intermediate account for the superiority of (CoO x -Mo 2 N). • An amendment theory is proposed towards conventional dual spatially separated co-catalysts for water splitting. Conventional theory of dual co-catalysts on a semiconductor in overall water splitting is that the dual co-catalysts spatially separated for photocatalytic H 2 and O 2 evolution, respectively. However, this theory ignores the use of the surface exciton and the water as a whole molecular for splitting. Here, we put forward a new Yin-Yang hybrid co-catalyst (CoO x -Mo 2 N) with opposite functions for each component for efficient water splitting. The (CoO x -Mo 2 N) / Ge 3 N 4 shows activities 1.5 times higher than that Ge 3 N 4 loaded with the spatial separated dual co-catalysts CoO x and Mo 2 N. The super properties of the Yin-Yang hybrid are attributed to the adjacent spatial configuration for extra use of surface excitons, more favorable water molecular absorption and two electrons reactive path with H 2 O 2 as intermediate involved in water splitting. It is proposed an amendment theory for conventional dual spatially separated co-catalysts by extra using surface exciton via spatially adjacent Yin-Yang hybrid co-catalyst. [ABSTRACT FROM AUTHOR]

Abstract: The ZnO microrods modified by Cu2O nanocrystals were prepared in aqueous solution. ZnO microrods acted as carrier to immobilize the Cu2O nanocrystals and improved the recovery rate from solution. The ZnO/Cu2O compounds promoted the separation of photo-induced electrons and holes, which was proved by surface photovoltage spectroscopy (SPS). Therefore, the compounds showed an enhanced photocatalytic activity than pure ZnO and pure Cu2O under both UV–vis light and visible light. [Copyright &y& Elsevier]

Abstract: The ZnO nanorods (diameter of 40nm and 100nm) were modified with Ru(dcbpy)2(NCS)2 (RuN3), and their responses to formaldehyde were measured at room temperature. All the results showed that the responses to formaldehyde of modified ZnO were higher than that of bare ZnO; especially the responses of modified ZnO nanorods with diameter of 40nm–5ppm formaldehyde was about 200% higher than that of bare ZnO. The UV–vis absorption spectrum and transient photovoltage analysis showed that the high responses of modified ZnO mainly arose from the strong photocatalytic oxidizing effect induced by the increasing of the absorption and photo-generated electron–hole separation. Our results demonstrate that the modification of RuN3 is a promising approach on improving the formaldehyde responses of ZnO nanorods. [Copyright &y& Elsevier]

Abstract: A water–dichloromethane interface-assisted hydrothermal method was employed to grow rutile TiO2 nanowires (NWs) on electrospun anatase TiO2 nanofibers (NFs), using highly reactive TiCl4 as precursor. The water–dichloromethane interface inhibited the formation of rutile NWs in water phase, but promoted the selective radial growth of densely packed rutile NWs on anatase NFs to form a branched heterojunction. The density and length of rutile NWs could be readily controlled by varying reaction parameters. A formation mechanism for the branched heterojunction was proposed which involved (1) the entrapment of rutile precursor nanoparticles at water–dichloromethane interface, (2) the growth of rutile NWs on anatase NFs via Ostwald ripening through the scavengering of interface-entrapped rutile nanoparticles. The heterojunction formed at anatase NF and rutile NW enhanced the charge separation of both under ultraviolet excitation, as evidenced by photoluminescence and surface photovoltage spectra. The branched TiO2 heterostructures showed higher photocatalytic activity in degradation of rodamine B dye solution than anatase NFs, and the mixture of anatase NFs, and P25 powders, which was discussed in terms of the synergistic effect of enhanced charge separation by anatase–rutile heterojunction, high activity of rutile NWs, and increased specific area of branched heterostructures. [Copyright &y& Elsevier]

Abstract: ZnO nanostructures materials with two-dimensional (2D) plate-like and three-dimensional (3D) flower-like morphologies have been synthesized via facile hydrothermal process. Scanning electron microscopy (SEM), high resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD) have been used to characterize the samples. We have compared the surface photoelectric properties of flower-like ZnO with that of plate-like ZnO by means of surface photovoltage (SPV), field-induced surface photovoltage (FISPV), transient photovoltage (TPV) and surface photocurrent (SPC) techniques. Based on the photovoltage responses, the influence of the morphology on transfer characteristics of photogenerated charge carriers was discussed. The synthesized flower-like ZnO exhibited more efficient separation and transfer properties of photogenerated charge carriers than that of plate-like ZnO in the UV region due to the special flower-like hierarchical nanostructures. We have also evaluated the photocatalytic activity of the ZnO samples by photodegradation efficiency of RhB. The experiments demonstrated that RhB in aqueous solution was more efficiently photodegraded using flower-like ZnO than plate-like ZnO. The results also show the consistency between the carrier dynamics of photogenerated electron–hole pairs and photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Different morphologies of monoclinic BiVO4 with smaller size were hydrothermal synthesized by simply adjusting the amount of surfactant (polyvinyl pyrrolidone PVP K30) added. The detailed field emission scanning electron microscope (FESEM) analysis revealed that the amount of PVP added could significantly affect the morphology and size of BiVO4. Their photocatalytic activities were evaluated by the decolorization of methylene blue (MB) aqueous solution under visible-light irradiation (λ >400nm), and the as-prepared sample with well-assembled flower-like morphology showed a much higher photocatalytic activity due to larger specific surface area and higher separation efficiency of photo-induced carriers. The relationship between the behavior of photo-induced carriers and photocatalytic activity was studied using the surface photovoltage spectroscopy (SPS) and corresponding phase spectra. [Copyright &y& Elsevier]

Abstract: Nanosized TiO2 photocatalysts of anatase, rutile and mixed-phase were synthesized through hydrolysis method. The influence of the interface junction between anatase and rutile TiO2 on the photo-generated charge carriers properties were studied by Kelvin probe (KP), surface photovoltage (SPV) and transient photovoltage (TPV) techniques. The KP results revealed that the difference of the surface work function between anatase and rutile might cause the formation of built-in field at the interface in mixed-phase TiO2. The role of the interface junction was further testified through the characteristics of photo-generated charge carriers by SPV and TPV. [Copyright &y& Elsevier]

Abstract: Carbon-doped anatase TiO2 was prepared by a facile hydrothermal process without adding additional carbon source. The as-prepared sample shows highly efficient photocatalytic activity, which only requires 4min and is about 11 times higher than that of Degussa P25 TiO2 in degradation of methyl orange (MO) dye under UV light irradiation. Moreover, a highly visible-light activity is also observed. UV–vis diffuse reflectance spectra and X-ray photoelectron spectroscopy confirm that the carbon atoms are incorporated into the interstitial positions of TiO2 lattice and form a strong interaction with titanium atoms and extend photoresponding range to 700nm. Surface photovoltage spectra (SPS) and transient photovoltage (TPV) suggest that the presence of interstitial carbons induce several localized occupied states in the gap, enhance the separation extent and restrain the recombination of the photo-induced electron and hole carriers in TiO2. [Copyright &y& Elsevier]

Abstract: The ZnO nanorods with different diameters (∼300, 100, 40nm) and nanoparticles (∼6nm) were prepared, and their sensitivities to formaldehyde at room temperature were measured with and without the UV light irradiation (the intensity of light is 0.155mW/cm2). The XRD, TEM and SEM were utilized to examine the size of crystal and the morphology of material. The transient photovoltage and photoluminescence spectra were utilized to investigate the photoelectric properties of ZnO. The ZnO nanorods with diameter of ∼40nm own the highest response to formaldehyde with the UV light illumination than that of other samples. It is attributed to the large surface-to-volume ratio and high photo-generated charge efficiency, which are two key parameters to determine the gas response. The transient photovoltage results further demonstrate that the photo-generated charge efficiency of gas sensing element decreases as the surface-to-volume ratio increases (i.e. the size of crystal decreases). Therefore, the particles with highest sensitivity are of a certain size, neither the largest nor the smallest tested. Our work may supply a direction to fabricate the high performance gas sensor with UV light illumination. [Copyright &y& Elsevier]

Abstract: Zinc oxide nanorods were synthesized using a simple hydrothermal method. Formaldehyde-sensing characteristics were investigated without and with ultraviolet (UV) light irradiation. The gas response of nanorods to 110ppm formaldehyde with UV light irradiation was about 120 times higher than that without UV light irradiation. The detection limit was as low as 1.8ppm at room temperature. This high gas response under the UV light is attributed to photocatalytic oxidation. Furthermore, the significant improvements of the selectivity and recovery time were obtained after irradiating the nanorods with UV light. Our results demonstrated that applying UV light irradiation on the zinc oxide nanorods is an effective approach to achieve higher response and excellent selectivity to formaldehyde at room temperature. [Copyright &y& Elsevier]

• Different amount of Pt cocatayst was loaded on anthracene-based MOF, Zr–ADBEB, by post chemical reduction. • Performance of the Zr–ADBEB photocatalyst is dependent on the amount of the Pt cocatalyst loaded. • H 2 evolution rate of the Zr–ADBEB photocatalyst decorated by optimal amount of Pt is ca. 220 times of the pristine one. In this work, an anthracene-based MOF, Zr–ADBEB, was prepared by coordination reaction of zirconium chloride and 4,4′-anthracene-9,10-diylbis(ethyne-2,1-diyl) dibenzoic acid (ADBEB). After the loading of different amount of Pt nanoparticles by post chemical reduction of hexachloroplatinic acid with sodium borohydride, the MOF presented greatly improved activity towards visible light hydrogen (H 2) evolution. It was identified that band bending of the MOF is downward towards surface, which is effective to promote separation of the photogenerated charge carriers and transportation of the photogenerated electrons from the MOF to the Pt cocatalyst to contribute to the H 2 evolution. The Zr–ADBEB MOF photocatalyst decorated by optimal amount of Pt cocatalyst, i.e., 1.0 wt%, exhibited a H 2 evolution rate as high as 704 μmol·h−1·g−1, ca. 220 times of that of pristine Zr–ADBEB MOF (3.2 μmol·h−1·g−1). [ABSTRACT FROM AUTHOR]

Abstract: Developing photocatalysts with specific morphology promises good opportunities to discover the geometry-dependent properties. Herein, flower-like anatase TiO2 assemblies with dominant {001} facets exposed were successfully synthesized via a simple, economical hydrothermal route with titanium sulfate and hydrofluoric acid. Their surface morphology and structure were investigated by scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, X-ray diffraction, and Brunauer–Emmet–Teller N2 gas adsorption–desorption isotherms. The optical property and the photo-induced charge carriers of the flower-like TiO2 were studied by UV–vis diffuse reflectance spectroscopy and transient photovoltage technique. The flower-like TiO2 particles exhibited a good photocatalytic activity in degrading rhodamine B. [Copyright &y& Elsevier]

• ZnIn 2 S 4 /WO 3 nanocomposites were fabricated by self-assembly of ZnIn 2 S 4 in the presence of preformed WO 3 ·H 2 O. • PtS and MnO 2 were selectively loaded on ZnIn 2 S 4 and WO 3 in the ZnIn 2 S 4 /WO 3 nanocomposites, respectively. • PtS-ZnIn 2 S 4 /WO 3 -MnO 2 show superior photocatalytic activity for water splitting. • An efficient coupling of PtS-ZnIn 2 S 4 and MnO 2 -WO 3 via a Z-scheme charge transfer pathway. ZnIn 2 S 4 /WO 3 nanocomposites, with ZnIn 2 S 4 nanosheets loaded on WO 3 nanorods, were synthesized by self-assembly of hexagonal ZnIn 2 S 4 in the presence of preformed WO 3 ·H 2 O nanoplates. PtS and MnO 2 , the co-catalysts for H 2 and O 2 evolution, respectively, were selectively loaded on ZnIn 2 S 4 and WO 3 in the nanocomposites. The resultant PtS-ZnIn 2 S 4 /WO 3 -MnO 2 nanocomposites show photocatalytic activity for overall water splitting to produce H 2 and O 2 under visible light. An optimum activity was achieved over 0.5%PtS-20%ZnIn 2 S 4 /WO 3 -3.0%MnO 2 , in which 5.94 μmol of H 2 and 2.24 μmol O 2 were evolved in 8 h. The apparent quantum yield (AQY) for H 2 evolution was determined to be ca. 0.50% at 420 nm. The superior photocatalytic activity for overall water splitting over PtS-ZnIn 2 S 4 /WO 3 -MnO 2 nanocomposites can be ascribed to an efficient coupling of photocatalytic water reduction over PtS-ZnIn 2 S 4 and photocatalytic water oxidation over MnO 2 -WO 3 via a Z-scheme charge transfer pathway. This study demonstrates a high potential of fabrication of the all-solid Z-scheme photocatalytic systems for overall water splitting. [ABSTRACT FROM AUTHOR]