Search

In this study, Ce3+-doped ZnO nanomaterials with different concentrations were prepared by hydrothermal method. The prepared samples were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS), photo-luminescence (PL), and Brunauer Emmett Teller (BET). Among them, XRD confirmed the successful doping of Ce3+, PL showed that Ce3+-doped inhibited the recombination of electron-hole pairs, and BET found that Ce3+-doped increased the specific surface area of ZnO. Photodegradation experiments were performed on aqueous solutions of Rhodamine B (RhB) under simulated daylight conditions. The experiments results showed that the photocatalytic performance of all Ce3+-doped samples was better than that of undoped ZnO. It was found that the sample (.1 % Ce3+ doped ZnO) exhibited the best photocatalytic performance (degradation efficiency of 95.6%). The photocatalytic mechanism of Ce3+doped ZnO was also presented. [ABSTRACT FROM AUTHOR]

For the dye-sensitized heterogeneous photocatalytic system, the main challenge is the design of support materials with low cost, good adsorption capacity and facilitated electron transfer ability. Herein, an amorphous/crystalline SnO 2 /BaSO 4 composite with unique leaf-like morphology composed of four protruded corners was developed by an one-pot coprecipitation method at room temperature. The low-cost crystalline BaSO 4 acted as the support material for Eosin Y (EY) sensitization and did not inhibit the light absorption of EY, and the amorphous SnO 2 uniformly coated on BaSO 4 provided good conductivity to benefit for the transport of photogenerated carriers. Therefore, under visible-light irradiation (λ ≥ 420 nm), the EY-sensitized SnO 2 /BaSO 4 showed excellent photocatalytic activity with H 2 -production rate of 263 μmol h−1, which was 7.5 times that of EY or EY-sensitized bare BaSO 4 , and the apparent quantum yield achieved to be 11.2 % at 500 nm. [Display omitted] [ABSTRACT FROM AUTHOR]

As for the composite photocatalysts, the carrier transfer mechanism at the heterojunction has a very important impact on their photocatalytic performances. In this work, the bandgap of ZnxCd1‐xS‐DETA can be tuned by adjusting the ratio of Cd2+/Zn2+. With the change of the bandgap of ZnxCd1‐xS‐DETA, the carrier transfer mechanism at the ZnO/ZnxCd1‐xS‐DETA heterojunction changes from Type‐I to S‐scheme, and the photocatalytic properties of ZnO/ZnxCd1‐xS‐DETA nanocomposites also change. Among them, the ZnO/Zn0.5Cd0.5S‐DETA nanocomposite has the best photocatalytic hydrogen evolution activity under visible light, and its hydrogen evolution rate is 2.58 mmol g−1 h−1. In addition, after seven cycles, the ZnO/Zn0.5Cd0.5S‐DETA nanocomposite photocatalyst has no significant decrease in hydrogen evolution rate, which is showing its excellent stability. This work reveals that the carrier transfer mechanism at the heterojunction of composite photocatalysts can be changed by the modulation of bandgap, which provides an effective idea for the development of photocatalysts. [ABSTRACT FROM AUTHOR]

Heterostructured photocatalysts are promising candidates in the photocatalysis field, and the heterojunction plays a vital role in the separation of spatial charge carriers. Here, a heterojunction was fabricated by the in situ growth of ultrathin Bi 12 O 17 Cl 2 (BOC) nanosheets (NSs) onto porous g-C 3 N 4 (PGCN) NSs. The NSs' nanostructure can effectively shorten the diffusion path of charge carriers and thus promote interfacial charge migration, which can improve the surface photocatalytic activity. The X-ray photoelectron spectroscopy spectra and the experimental measured Fermi level (E F) indicate that electrons transfer from PGCN to BOC, which leads to the formation of the built-in electric field with the orientation from PGCN to BOC. Driven by the built-in electric field, the charge carriers transfer through a step-like pathway. This step-scheme porous g-C 3 N 4 /Bi 12 O 17 Cl 2 (PGCN/BOC) heterostructured nanocomposite displays an enhanced photocatalytic performance compared with pure BOC and PGCN. This work provides new insight into the novel construction of a step-scheme heterojunction toward photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

Recently, cadmium selenide (CdSe) has been deeply studied because of its excellent photocatalytic hydrogen (H2) production performance. However, pure CdSe has poor stability and severe photocorrosion, which seriously affect its application prospect. In this work, we successfully deposit Bi2MoO6 on an inorganic–organic CdSe-diethylenetriamine (DETA) hybrid to design Bi2MoO6/CdSe-DETA composites by an in situ solvothermal method. The morphology, crystal structure, electrochemical properties, H2 evolution performance and the photostability of Bi2MoO6/CdSe-DETA composites are explored using various techniques. The results show that the as-prepared Bi2MoO6/CdSe-DETA composites exhibit excellent photocatalytic performance and photostability under visible light irradiation. Among them, the Bi2MoO6/CdSe-DETA hybrid system exhibits excellent photocatalytic H2 production performance (5.92 mmol g−1 h−1), which is approximately 3.6 and 1.8 times higher than that of pure CdSe and CdSe-DETA, respectively. After 4 cycles, the photocatalyst still maintains high H2 production. This study develops a new type of photocatalyst that can respond to visible light. This provides an effective way to solve the energy problem by using solar energy. [ABSTRACT FROM AUTHOR]

Cadmium sulfide (CdS) is a promising semiconductor material for photocatalytic hydrogen (H 2 ) evolution. However, the serious photocorrosion and low visible-light utilization limit its practical application. In this work, cerium oxide (CeO 2 ) modified inorganic-organic CdS-diethylenetriamine (CeO 2 /CdS-DETA) composite material with different mass ratios was fabricated by hydrothermal method. Crystal structure, light absorption properties, microstructure, photocatalytic H 2 production activity, photocurrent and fluorescence spectra of the composites were investigated. The results exhibited that photocatalytic performance of CeO 2 /CdS-DETA materials was improved and 7%CeO 2 /CdS-DETA exhibited excellent catalytic activity (14.84 mmol g -1  h -1 ) under visible light irradiation (λ ≥ 420 nm), which is twice more than that of CdS-DETA. Moreover, the photocatalytic mechanism was preliminarily discussed. This work not only promotes the development of novel inorganic-organic CdS-DETA-based photocatalytic materials for solar energy utilization but provides sustainable photocatalysts by taking both photocatalytic H 2 production and repeated utilization into consideration. [ABSTRACT FROM AUTHOR]

More and more serious energy crisis and greenhouse effect force people to find the appropriate solutions. Photocatalytic reduction of CO 2 into hydrocarbon fuels is one of the most potential strategies. In this paper, novel one-dimensional (1D) carbon nanofibers@TiO 2 core-shell nanocomposites have been prepared via electrospun synthesis of carbon nanofibers core followed by in situ growth of TiO 2 shell, which exhibit a 2.3-fold higher photocatalytic activity than the pure TiO 2 . The increase of catalytic performance attributed to higher specific surface areas of carbon nanofibers@TiO 2 core-shell nanocomposites for providing more surface-active sites. Moreover, the black carbon nanofibers promote light absorption, and the light energy can be converted into heat energy that can speed up the diffusion of reactants and products. Most importantly, the carbon nanofibers with good electrical conductivity can speed up the separation of the photo-induced electron and hole pairs in photocatalyst. This work provides a good synthesis of 1D core-shell heterostructure, and proves that the carbon nanofibers can be an ideal cocatalyst for enhancing photocatalytic CO 2 reduction performance of TiO 2 . [ABSTRACT FROM AUTHOR]

In this work, we have developed a simple synthetic approach of nanosheet-assembled BiOCl/BiOBr microspheres by an ethylene glycol (EG)-assisted hydrothermal method. The crystalline form, morphology, chemical composition, optical performance and surface area of BiOCl/BiOBr microspheres were identified using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy spectra (EDX), UV–vis diffuse reflectance spectroscopy (DRS) analysis, high resolution X-ray photoelectron spectra (XPS) and N 2 adsorption-desorption isotherms. BiOCl/BiOBr microspheres were nanosheet-assembled particles, which possessed visible light absorption under LED light irridation. Additionally, the methylene blue (MB) photodegradation performance of different BiOCl/BiOBr microspheres irradiated under 410 nm LED light arrays were investigated, the results exhibited that as-prepared BiOCl/BiOBr products showed higher catalytic effiency than pure BiOCl or BiOBr. By optimizing the composition ration of the BiOCl and BiOBr, up to 93% degradation rate can be obtained in the 40%BiOCl/BiOBr microspheres. Finally, the photocatalytic mechanism of BiOCl/BiOBr microspheres had been proposed. [ABSTRACT FROM AUTHOR]

Element doping is an efficient strategy for tuning the electronic structure and improving the photocatalytic activity of graphitic carbon nitride (g-C 3 N 4 ). Employing the density functional theory computation performed by CASTEP module, we investigated the band structures, electronic and optical properties of monolayer g-C 3 N 4 doped with halogens (F, Cl, Br or I). First, the halogen atoms occupying the interstitial space enclosed by three tri-s-triazine units in the monolayer g-C 3 N 4 unit cell was demonstrated to be the most stable configuration in terms of adsorption energy. On the basis of these interstitial-doped monolayer g-C 3 N 4 systems, it is found that the introduction of halogen atoms leads to various density of states (DOS) and redistribution of the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO). The F atom tends to occupy the valance band and HOMO due to its extremely high electronegativity. By contrast, the Cl, Br and I atoms are involved in the conduction band and LUMO. In sum, the calculation results show that the halogen-doped monolayer g-C 3 N 4 systems have narrowed band gap, increased light absorption and reduced work function, which are conducive to high photocatalytic activity. The conclusions presented in this work indicate the availability of halogen-doped monolayer g-C 3 N 4 with considerable photocatalytic performance. [ABSTRACT FROM AUTHOR]

Plasmonic Ag 2 MoO 4 /AgBr/Ag composite is fabricated by in-situ ion exchange and reduction methods at room temperature. The samples are characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance (DRS), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM) and photoluminescence (PL) measurements. The results show that butterfly-like Ag 2 MoO 4 nanosheets served as the precursor, and Ag 2 MoO 4 /AgBr/Ag is formed in phase transformation with MoO 4 2− displaced by Br − . The ternary Ag 2 MoO 4 /AgBr/Ag composite photocatalysts show greatly enhanced photocatalytic activity in photodegrading methylene blue (MB) under visible light irradiation compared with AgBr and Ag 2 MoO 4 . The pseudo-first-order rate constant k app of Ag 2 MoO 4 /AgBr/Ag is 0.602 min −1 , which is 11.6 and 18.3 times as high as that of AgBr and Ag 2 MoO 4 , respectively. Meanwhile, the efficiency of degradation still kept 90% after ten times cyclic experiments. Eventually, possible photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]

In this paper, novel Z-scheme porous graphitic C 3 N 4 (Pg-C 3 N 4 )/Ag 3 PO 4 composite was synthesized by a facile and green method at room temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and UV–vis diffuse reflectance spectroscopy (DRS) were used to characterize the structural, crystal and optical properties of the as-prepared nanocomposites. Photocatalytic activity of catalysts is evaluated by degrading methylene blue (MB) under visible light irradiation. The results showed that photocatalytic activity of Pg-C 3 N 4 /Ag 3 PO 4 was much higher than that of Pg-C 3 N 4 and Ag 3 PO 4 . The kinetic constant K app of MB degradation over Pg-C 3 N 4 /Ag 3 PO 4 was 1.45 and 9.6 times as high as that of Ag 3 PO 4 and Pg-C 3 N 4 , respectively. Finally, Z-scheme photocatalytic mechanism is proposed. [ABSTRACT FROM AUTHOR]

The optical and catalytic performances of materials strongly depend on their size, morphology, dimensionality and structure. Herein, we demonstrate a facile one-pot template free synthesis of hierarchical CdMoO 4 porous microspheres via a simple low temperature oil bath method. The photoactivity of the as-prepared samples was evaluated by photocatalytic decolorization of Methyl Orange (MO) and Methylene Blue (MB) mixed dye aqueous solutions at ambient temperature under full solar spectrum. The results indicated that the concentration of ammonium molybdate and reaction time greatly influence the diameter, average crystallite size, specific surface area, pore structure and photocatalytic activity of the prepared samples. Especially, under the suitable conditions the prepared hierarchical CdMoO porous microspheres exhibited enhanced photocatalytic activity and high stability. Furthermore, it is found that the photocatalytic activity and formation rate of hydroxyl radicals greatly depend on the particle sizes and morphology of as-prepared samples. This work not only demonstrates a simple way to fabricate the hierarchical CdMoO 4 porous microspheres but also shows a possibility for utilization of CdMoO 4 porous microspheres for the photocatalytic treatment of waste water pollutants. [ABSTRACT FROM AUTHOR]

The photocatalytic activity of bismuth oxyhalides largely depends on their morphologies and microstructures. In this work, hierarchically structured bismuth oxyiodide (BiOI) with tunable ratios of (1 1 0) and (0 0 1) facets are fabricated through a facile route combining solid-state reaction with subsequent hydrolysis at room temperature. The hierarchical structures endow BiOI with excellent visible-light photocatalytic performance for phenol degradation. Besides, the optimal ratio of (0 0 1) and (1 1 0) surfaces also plays an important role in enhancing the photocatalytic activity of BiOI. DFT calculation demonstrates that a surface heterojunction formed between (0 0 1) and (1 1 0) surfaces can improve the separation of electrons and holes on different surfaces and thus enhance the photocatalytic activity. [ABSTRACT FROM AUTHOR]

In general, N-, C- and S-doped ZnO exhibit much higher phototcatalytic activity than the pure ZnO. However, the essential factors and underlying mechanism regarding the enhancement of photocatalytic activity are still unclear. In this work, the electronic structures, optical properties and effective masses of charge carriers are investigated by first-principle density functional theory calculation. Due to the nature of p-type doping, N and C doping can generate vacant states above the Fermi level and shift the conduction band into lower energy region, resulting in narrowing of band gap. Thus, N- and C-doped ZnO demonstrate much stronger light absorption in both visible and ultraviolet region. In contrast, because of the absence of vacant states, only limited enhancement of light absorption is observed for S-doped ZnO whose improved photocatalytic performance can only be attributed to the direct reduction of band gap. The calculation of the effective masses show that ZnO typically possess light electrons and heavy holes, confirming its intrinsic character of n-type semiconductor, while N, C and S doping can generally render electrons lighter and holes heavier, resulting in slower recombination rate of photogenerated electron–hole pairs. Noticeably, C doping can discourage such recombination to the greatest extent and separate electron–hole pairs most efficiently compared with N and S doping, serving as a potentially promising pathway to increase the quantum efficiency of ZnO-based photocatalysts. This work will provide some new insights into the understanding of doping effect over the enhancement of photocatalytic activity of N-, C- and S-doped ZnO. [ABSTRACT FROM AUTHOR]

Single-crystalline anatase TiO2 nanocubes with exposed {100} and {001} facets, prepared by hydrothermal and calcination methods, display especially high photocatalytic activity toward CO2 reduction to methane and methanol, due to the synergistic effects of better crystallization, a more negative conduction band position and co-exposed {100} and {001} facets. [ABSTRACT FROM AUTHOR]

CuO/F-TiO2 nanoparticle photocatalyst was prepared by ball milling. The photocatalyst was characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, and photoluminescence emission spectroscopy. The photocatalytic activity was evaluated by photocatalytic oxidation of rhodamine B and reduction of Cr2O72-. The results showed that, for F-TiO2 photocatalyst, the photooxidation activity increases remarkably with the increasing amount of NH4F up to 1.0 g, and the photoreduction activity decreases gradually with the increase in the amounts of NH4F. For the CuO/F-TiO2 photocatalyst, the photoreduction activity increases greatly with the increase in the amount of doped p-CuO up to 1.0 wt.%, and the photooxidation activity decreases rapidly with the increase in the amounts of doped p-CuO. Compared with pure TiO2, the photoabsorption wavelength range of the CuO/F-TiO2 and F-TiO2 photocatalysts red shifts and improves the utilization of the total spectrum. The effect of ball milling time on the photocatalytic activity of the photocatalysts was also investigated. The mechanisms of influence on the photocatalytic activity of the photocatalysts were also discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrathin InVO 4 /CdSe-amine nanocomposite is obtained. • The nanocomposite exhibited excellent photocatalytic CO 2 reduction and stability. • Mechanism of charge transfer and separation in S-scheme heterojunction is proposed. • S-scheme photocatalytic mechanism is discussed. The formation of interfacial chemical bonding in heterostructures plays an important role in the transport of carriers. Herein, we firstly prepared ultrathin InVO 4 nanosheet (Ns) with a thickness of 1.5 nm. Diethylenetriamine-modified CdSe (CdSe-DETA) nanobelts are in-situ deposited on the surface of ultrathin InVO 4 Ns to build a InVO 4 /CdSe-DETA step-scheme (S-scheme) heterojunction photocatalysts. The protonated DETA acts as an amine-bridge to promote the formation of a tight chemical bond at the interface of InVO 4 /CdSe-DETA, thereby promoting the transfer of carriers at the interface. For photocatalytic CO 2 reduction, the rationally designed InVO 4 /CdSe-DETA S-scheme photocatalyst exhibits a remarkable CO generation rate of 27.9 µmol h−1 g−1 at 420 nm, which is 3.35 and 3.39 times higher than that of CdSe-DETA and InVO 4 Ns, respectively. The new method by using interfacial chemical bonding to facilitate interfacial charge transportation provide a promising strategy for improve photocatalysis. [ABSTRACT FROM AUTHOR]

Abstract Semiconductor heterojunction represents a family of promising photocatalysts for visible-light photocatalysis. In this work, a novel ternary g-C 3 N 4 /ZnS/SnS 2 heterostructure has been designed and synthesized by a facile one-step hydrothermal method. The obtained ternary g-C 3 N 4 /ZnS/SnS 2 heterostructures exhibited high photocatalytic activity in photodegradation of organic pollutants and photocurrent response irradiated by 410 nm LED light. The results demonstrated that the formation of the heterostructures can much improve the excellent photocatalytic activity if the lattice and energy level matching among the three semiconductors be satisfied, which causes efficient separation of photoinduced carriers, resulting in the high photodegradation of methylene blue (MB). As a result, the highest apparent rate constant K app of g-C 3 N 4 /ZnS/SnS 2 hybrid is 0.148 min−1, which is 8.74, 3.22 and 37.01 times as high as that of pristine g-C 3 N 4 , SnS 2 and ZnS, respectively. Graphical abstract Image 1 Highlights • g-C 3 N 4 /ZnS/SnS 2 composite is successfully synthesized by facile process. • The composite showed visible light activity for dye degradation. • The composite showed excellent photostability. • Charge carrier transfer pathways are proposed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pg-C 3 N 4 /Ag 2 MoO 4 composite is successfully synthesized by facile process. • The composite showed visible light activity for dye degradation. • The composite showed excellent photostability. • Charge carrier transfer pathways are proposed. Abstract Rapid recombination of photogenerated carriers has always been an important factor limiting advanced photocatalyst design. In this work, two-dimensional (2D) composites were successfully synthesized. Besides, crystal structure, micromorphology, optical properties, electrochemical properties, along with the photocatalytic methylene blue (MB) performance and photostability have been systematically explored. Porous graphite carbon nitride (Pg-C 3 N 4) was composited with Ag 2 MoO 4 forming a large-scale heterojunction interfaces, which is not only beneficial to supply more reaction active sites for catalytic reaction, but reduce the distance during the photoexcited carriers transfer. In addition, Ag surface plasmon resonance (SPR) effect acts as a very important role in photodegradation process, which makes great contributions to boosting the separation of photoexcited electron-hole pairs. The Pg-C 3 N 4 /Ag 2 MoO 4 composites exhibit an excellent photocatalytic MB degradation and photostability, which can degrade MB solution by 99.5% in 12 min. The k app of 40%Pg-C 3 N 4 /Ag 2 MoO 4 is 0.33065 min−1, which is much higher than that of Pg-C 3 N 4 (0.01606 min−1) and Ag 2 MoO 4 (0.00933 min−1). Moreover, trapping experiment was employed to determine the specific reactive species, indicating that hole plays a major role in MB photodegradation. This work provides an available method to conduct a 2D photocatalyst with large-scale heterojunction, which is a promising material for the application in photocatalytic water pollution treatment. [ABSTRACT FROM AUTHOR]

In this research work, we successfully prepared the Z-scheme BiVO 4 /porous graphite carbon nitride (Pg-C 3 N 4 ) composite by hydrothermal process at 180 °C, which realized strong redox capability under visible light, which was proved by enhanced photocatalytic degradation of methylene blue solution. The k app of 60%BiVO 4 /Pg-C 3 N 4 was 0.05251 min −1 , which was 4.6 and 7.2 times higher than that of BiVO 4 (0.00938 min −1 ) and Pg-C 3 N 4 (0.00643 min −1 ), respectively. The separation of charge carriers was effectively promoted, which was revealed by photoluminescence (PL) spectra and transient photocurrent response. Eventually, possible mechanism was also proposed. [ABSTRACT FROM AUTHOR]

In this paper, novel Z-scheme octahedral Cu 2 O/Ag 3 PO 4 composites are fabricated by a facile chemical method at low temperature. Field emission scanning electron microscope (FESEM), UV–Vis diffuse reflectance spectroscopy (DRS), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) are used to investigate the crystal structure and optical properties of the as-prepared nanocomposites. Photocatalytic activity of catalysts is displayed by methylene blue (MB) removal under visible light irradiation. The results show that photocatalytic performance of Cu 2 O/Ag 3 PO 4 is much higher than that of Cu 2 O and Ag 3 PO 4 , and the kinetic constant k app of MB degradation over Cu 2 O/Ag 3 PO 4 is 0.30447 min −1 , which is 7.0 and 2.1 times as high as those of Cu 2 O and Ag 3 PO 4 , respectively. Finally, the possible separation mechanism of electrons and holes is proposed. [ABSTRACT FROM AUTHOR]

A novel hierarchical Ag 2 WO 4 /Ag/Bi 2 MoO 6 ternary visible-light-driven photocatalyst was successfully synthesized by in situ doping Ag 2 WO 4 with Bi 2 MoO 6 nanosheets through a facile hydrothermal and photochemical process. The morphology, structure, optical performance and crystallinity of the products were measured by field emission scanning electron microscope (FESEM), energy dispersive spectrometer (EDS), UV–vis diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD). The results showed that Ag 2 WO 4 /Ag was uniformly dispersed on the surface of Bi 2 MoO 6 nanosheets. The photocatalytic performance of Ag 2 WO 4 /Ag/Bi 2 MoO 6 heterostructures was evaluated by the degradation of methylene blue (MB) under 410 nm LED arrays. The ternary Ag 2 WO 4 /Ag/Bi 2 MoO 6 nanocomposite exhibits higher photocatalytic activity than Bi 2 MoO 6 and Ag 2 WO 4 . The synergistic effect of Ag 2 WO 4 and Bi 2 MoO 6 could generated more heterojunctions which promoted photoelectrons transfer from Ag 2 WO 4 to Bi 2 MoO 6 , leading to the improvement of photocatalytic performance by photoelectrons-holes recombination suppression. At the same time, the surface plasmon resonance of Ag 2 WO 4 /Ag/Bi 2 MoO 6 is another crucial reason for the high photocatalytic performance of organic pollutants degradation. And the 20 wt% Ag 2 WO 4 -loaded Bi 2 MoO 6 shows the optimal photocatalytic performance in the degradation of MB. In addition, the ternary composites can be easily reclaimed by precipitation and exhibits high stability of photocatalytic degradation after five recycles. [ABSTRACT FROM AUTHOR]

The band engineering of visible-light-driven photocatalysts is a promising route for harnessing of effective solar energy to perform high chemical reactions and to treat environmental pollution. In this study, two narrow band gap semiconductor nanomaterials, graphitic carbon nitride (g-C 3 N 4 ) and Bi 2 MoO 6 , were selected and coupled to form series of g-C 3 N 4 /Bi 2 MoO 6 photocatalysts. Their structure, light absorption wavelength range, charge transport properties and energy level were investigated. Through perfect manipulation of their composition, enhanced photocatalytic activity of the Z-scheme g-C 3 N 4 /Bi 2 MoO 6 photocatalysts with efficient reduction of recombination of photogenerated electrons and holes was achieved. The optimized Z-scheme g-C 3 N 4 /Bi 2 MoO 6 photocatalysts with 25 wt%g-C 3 N 4 showed apparent pseudo-first-order rate constant k app as high as 0.0688 min −1 , which was 4.8 times and 8.2 times higher than that of g-C 3 N 4 and Bi 2 MoO 6 photocatalyst, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Niobium carbide (NbC) powders were prepared via a novel route at 550°C and 8h, using metallic magnesium powders, niobium pentoxide (Nb2O5), and potassium acetate (CH3COOK) as starting materials. The structure and morphology of the product were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that as-prepared product was crystallized in pure cubic NbC phase and the size of the sample was estimated to be around 120nm. The Rietveld refinement of the XRD data gives the cell constant a =4.4718Å. According to the Scherrer formula, the real grain size was about 70nm. The BET surface area of the sample was ca.29.3m2/g. The grain size distribution of the sample was about 467nm, which was characterized by N4 PLUS submicron Particle Size Analyzer. The cubic NbC powders exhibited photocatalytic activity in degradation of Rhodamine-B (RhB) under 300W mercury lamp light irradiation. [Copyright &y& Elsevier]

In this work, BiOBr was firstly prepared by using a facile solvothermal approach at 393 K for 24 h, and then Bi 2 MoO 6 well dispersed on the surface of BiOBr at 433 K for 3 h. The shape, chemical composition, crystal structure, optical property and surface area of Bi 2 MoO 6 /BiOBr were investigated by field emission electron microscope (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N 2 adsorption-desorption isotherms and UV–Vis diffuse reflectance spectroscopy (DRS). The Bi 2 MoO 6 /BiOBr heterojunctions exhibited substantially improved performance for removal of methylene blue (MB), compared with BiOBr and Bi 2 MoO 6 samples under 410 nm light excitation. The constant K app of 20%Bi 2 MoO 6 /BiOBr is 0.0539 min −1 , which is 4.4 and 6.9 times higher than that of Bi 2 MoO 6 (0.0121 min −1 ) and BiOBr (0.0078 min −1 ). The prominent enhancement of activity is due to the high charge separation capacity, which resulted from the matched band alignment of two components. Finally, the Z-scheme photocatalytic mechanism was confirmed by radical trapping experiment. [ABSTRACT FROM AUTHOR]

CdIn 2 S 4 , CdS and In 2 S 3 photocatalysts were fabricated via a facile solvothermal method using indium chloride, cadmium nitrate and thiacetamide as precursors. The physicochemical and optical properties of the as-prepared samples were characterized by a series of techniques. The photocatalytic activities of the as-prepared samples were evaluated by selective aerobic oxidation of aromatic alcohols to corresponding aldehydes under visible light illumination. Compared with pure In 2 S 3 and CdS samples, CdIn 2 S 4 photocatalyst shows superior photocatalytic performance for selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD). Under the optimal conditions, the conversion and selectivity for photocatalytic selective oxidation of BA to BAD are 80.1 and 98.8% under visible light irradiation for 2 h, respectively. The excellent photocatalytic performance of CdIn 2 S 4 photocatalyst should be ascribed to its unique structure with a favorable absorptivity, appropriate conduction band and valence band positions and longer lifetime of photogenerated charge carriers. A possible reaction mechanism for selective oxidation of BA to BAD over CdIn 2 S 4 photocatalyst with O 2 and visible light is proposed. It is hoped that the current work could offer an avenue to prepare high-performance chalcogenide photocatalysts used in the field of photocatalytic selective organic transformations. [ABSTRACT FROM AUTHOR]

Highlights: [•] Electronic structures of NaBiO3 are elucidated based on DFT–GGA method. [•] The VB and CB of NaBiO3 have strong redox ability under visible light irradiation. [•] The distortion of BiO6 octahedra promotes the separation of electronic and hole. [•] The lighter effective masses facilitate the migration of photogenerated carriers. [Copyright &y& Elsevier]

A novel metal-free organic photocatalyst entitled polyphenylene sulfide with intrinsic polarization is designed and synthesized for effective photo-induced degradation of various organic pollutants and selective oxidation of benzyl alcohol to benzaldehyde. The polarization-induced spatial charge separation can effectively facilitate the transfer of photogenerated charges, thus largely enhancing the photocatalytic activities. • First report of a metal-free organic photocatalyst — polyphenylene sulfide (PPS). • The design and synthesis of PPS with intrinsic polarization. • It shows outstanding performance of charge separation. • PPS bears better photo-induced degradation and selective oxidation activities than g-C 3 N 4. Polarization has emerged as one of the most effective strategies for charge carriers separation in the bulk and on the surface of photocatalysts. Searching for novel photocatalysts with intrinsic polarity is a challenge to promote the progress of photocatalysis. Herein, a novel organic polymeric photocatalyst —— Polyphenylene sulfide (PPS) is introduced. Bearing the noncentrosymmetric structure and alternant arrangement of thioether bonds and benzene groups, the generated intrinsic polarization of PPS is proposed and proved. Compared with graphitic carbon nitride (g-C 3 N 4), PPS exhibits 1.33–5.53 times higher activities for the photodegradation of various contaminants and 50 % more effective performance on the photocatalytic oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) with high selectivity (96 %), which can be ascribed to the spatial separation of charges motivated by the polarization-induced electric field. The investigation of PPS will provide a fresh angle of view for the design and preparation of new metal-free photocatalysts. [ABSTRACT FROM AUTHOR]