Search

Bismuth vanadate (BiVO4) is a promising photocatalytic material for environmental governance and water splitting. However, the short photogenerated carrier lifetime and narrow visible-light response restrict its extensive applications. Herein, a novel electrospun method was developed to prepare bismuth (Bi) modified BiVO4 (Bi/BiVO4) porous nanofibers. Morphologies, structure and chemical states of the obtained samples were characterized using a series of analytical techniques. The photocatalytic performance of Bi/BiVO4 porous nanofibers was evaluated by photocatalytic degradation of methylene blue (MB) under visible light irradiation. The enhanced visible-light photocatalytic activity of Bi/BiVO4 can be attributed to the Bi nanoparticles with surface plasmon resonance (SPR) effect, as well as semiconductor character by extending the optical absorption of BiVO4 and restraining the recombination of electron-hole pairs during the photocatalytic degradation process, respectively. In this work, a new insight is taken into the fabrication of Bi/BiVO4 composite as an outstanding visible-light responsive photocatalyst, which facilitates its application in the field of environmental protection.

Semiconductor photocatalysis as an alternative technology has received extensive attention for addressing the worldwide energy and environment issues. However, it is still a great challenge and imperative to profoundly understand the migration mechanisms for achieving the complete utilization of photoexcited charge carriers. In this paper, a series of g-C 3N4/ZnIn2S4 heterojunction composites were fabricated by thermal polycondensation and solvothermal methods and then thoroughly characterized by a range of techniques. Photocatalytic selective oxidation of aromatic alcohols to corresponding aldehydes with O 2 under visible light irradiation was introduced as a model reaction system to evaluate the photocatalytic performance of the as-prepared samples. The results exhibit that when the main constituent of photocatalyst is ZnIn2S4, the transfer of the photogenerated charge carriers adopts a band-band mechanism in g-C3N4/ZnIn2S4 heterojunction composite. However, when the main constituent of photocatalyst is g-C3N4, the transfer of the photogenerated charge carriers adopts a Z-scheme mechanism. Therefore, the different compositions of the composite samples lead to the different electronic conductivities and then affect the direction of the built-in electric field in the relative p-n junction, finally causing the different transfer mechanisms of the photogenerated charge carriers for g-C3N4/ZnIn2S4 composite samples.

In this paper, we propose a new acetylenic carbon material called pyridyne, which is composed of acetylenic linkages and pyridine rings. From first-principles calculations, we investigate the structural, elastic and electronic properties of pyridyne. It is found that the structure of pyridyne is stable at 300 K and its stability is comparable to experimentally synthesized graphdiyne and graphtetrayne. Compared with graphene or graphyne, pyridyne possesses more diverse pores and reduced delocalization of electrons. The in-plane stiffness of pyridyne is 183 N m-1 with a Poisson's ratio of 0.304. Pyridyne is found to be a semiconductor with a direct band gap of 0.91 eV. The intrinsic electron mobility can reach 6.08 × 104 cm2 V-1 s-1, while the hole mobility can reach 1.82 × 104 cm2 V-1 s-1.

Ni-based phosphides (NiPx) composed of earth-abundant elements are promising cocatalysts to replace noble metals for photocatalytic H2 evolution reaction (HER). A safe, energy-saving, and composition-controllable synthesis of NiPx is still highly desired. A facile and mild solvothermal process was developed for the first time for selective synthesis of a series of NiPx, including Ni, Ni12P5, Ni2P/Ni12P5, Ni/Ni2P and Ni2P, through controlling the dosage of NaBH4 and NaH2PO2. The phosphidation process was mainly composed of (1) a sequential reduction of Ni2+ to Ni0 and (H2PO2)− to P (around the formed Ni0) triggered by NaBH4, and (2) a final phosphidation between Ni0 and the in situ generated P atoms. The photocatalytic HER performance of g-C3N4 can be substantially improved with the decoration of NiPx (3 wt%) as the separation of photoinduced charge carriers can be promoted and some active sites with low over-potential for HER can be introduced. The cocatalytic efficiency of NiPx is mainly determined by P content. Ni2P with a high ratio of P consequently exhibits the highest HER performance (215.1 µmol g−1 h−1), which is almost six times higher than that of the pristine g-C3N4 (35.6 µmol g−1 h−1). Thus, as for the cocatalyst based on Ni phosphides, Ni2P is the preferable crystal phase and more efforts should be devoted to Ni2P to further optimize its structure, texture, and morphology in future works.

Z-Scheme photocatalysts as a research focus perform strong redox capability and high photocatalytic performance. WO3/KNbO3 photocatalysts were fabricated by ball milling method, and performed higher photocatalytic activity in liquid degradation(rhodamine B, methylene blue and bisphenol A), compared with WO3 or KNbO3 monomer. This is due to that Z-scheme heterojunction is formed between WO3 and KNbO3, and the holes photoexcited in valence band of KNbO3 are quickly combined with the electrons in conduction band of WO3. The electrons accumulated in conduction band of KNbO3 show high reducibility, thereby reducing O2 to •O2−, and the holes in valence band of WO3 show high oxidative to oxidize H2O to •OH, respectively. Furthermore, it is proved by means of electron spin resonance(ESR) spectra, terephthalic acid photoluminescence probing technique(TA-PL), and UV-Vis absorption spectra of nitroblue tetrazolium. This work indicates that the fabrication of Z-scheme structure can improve the photocatalytic activity by efficiently separating the photogenerated electrons and holes in the photocatalytic reaction system, which is helpful to deeply understand the migration mechanism of photoexcited carrier(band-band transfer and Z-scheme transfer) in heterojunction photocatalysts.

A series of novel CdS/CdIn2S4 composite materials were prepared via a one-pot solvothermal process. The as-obtained photocatalysts were characterized by several techniques and the photocatalytic properties of CdS/CdIn2S4 photocatalysts were studied by photocascade synthesis of Schiff base compounds in a photocatalytic reaction system of aromatic alcohols and nitrobenzene irradiated with visible light. The results reveal that the resulting CdS/CdIn2S4 heterostructure samples show outstanding photocatalytic activities toward the photocascade production of Schiff base compounds in an aromatic alcohols and nitrobenzene reaction system irradiated with visible light. An optimized 50.0% CdS/CdIn2S4 heterostructure sample shows the highest Schiff base yield of 42.0% irradiated with visible light for 4 h, which is approximately 19.1 and 1.54 times higher than those of sole CdS and CdIn2S4 samples, respectively. The fabrication of heterogeneous structure improves the spatial separation and migration of photoinduced electron-hole pairs, thus contributing to the enhancement of photocatalytic properties. We foresee that this finding can offer a strategy to develop heterostructure composites for efficient synthesis of organics by photocatalysis under mild conditions.

In this study, a new photocatalytic reaction system for simultaneous selective oxidation of aromatic alcohols to corresponding aldehydes and reduction of protons to H2 has been developed. The results reveal that compared with pure ZnIn2S4, the ZnIn2S4 photocatalysts modified with noble metal gold (Au/ZnIn2S4) significantly promote the photocatalytic performance. Among them, the 0.5% Au/ZnIn2S4 nanosheets shows the highest photocatalytic activity for selective oxidation of benzyl alcohol to benzaldehyde and hydrogen production, and the yields of H2 and benzaldehyde are 326.68 and 352.04 μmol under visible light irradiation for 4 h, respectively. Those are about 4.4 and 3.6 times higher than those of pure ZnIn2S4 sample (74.0 μmol H2 and 98.04 μmol benzaldehyde), respectively. The utilization ratio of photogenerated electrons to holes can achieve 92.8%. Additionally, the control experiments demonstrate that the photogenerated electrons and holes play significant roles during the reaction process. It is hoped that the current work can offer an avenue to utilize the photogenerated carriers more efficiently and to develop other photocatalytic reaction systems, such as nitrogen fixation and reduction of carbon dioxide.

In a reaction system, the simultaneously efficient utilization of photogenerated electrons and holes to realize the photocatalytic selective redox reactions of organics has been a hot topic. In this paper, the Zn3In2S6 samples were synthesized via a simple solvothermal method with different solvents, which could make full use of photogenerated electrons and holes to achieve the photocatalytic selective transformation of aromatic alcohols to aromatic aldehydes and hydrogen evolution under mild conditions. The results show that the Zn3In2S6 synthesized with water (Zn3In2S6-W) exhibits the highest photocatalytic performance among the selected samples, with which the yields of benzaldehyde and hydrogen reach up to 732 and 708.8 μmol under light irradiation (λ ≥ 380 nm) for 4 h, respectively. The molar ratios between aldehydes and hydrogen are close to 1: 1. The apparent quantum efficiency is about 6.48% for wavelength λ = 380 ± 10 nm over Zn3In2S6-W sample. A possible reaction mechanism for the photocatalytic selective transformation of benzyl alcohol to benzaldehyde and hydrogen evolution under light irradiation is proposed. This work highlights that a reaction system is developed to effectively make use of the photogenerated electrons and holes for selective transformation of aromatic alcohols to aromatic aldehydes and hydrogen evolution over Zn3In2S6 photocatalysts under mild conditions.

The structural, elastic and electronic properties of 2D naphyne and naphdiyne sheets, which consist of naphthyl rings and acetylenic linkages, are investigated using first-principles calculations. Both naphyne and naphdiyne belong to the orthorhombic lattice family and exhibit the Cmmm plane group. The structural stability of naphyne and naphdiyne are comparable to those of experimentally synthesized graphdiyne and graphtetrayne, respectively. The increase of acetylenic linkages provides naphdiyne with a larger pore size, a lower planar packing density and a lower in-plane stiffness than naphyne. Naphyne is found to be an indirect semiconductor with a band gap of 0.273 eV, while naphdiyne has no band gap and has a Dirac point. The band gaps of naphyne and naphdiyne are found to be modified by applied strain in the elastic range. These facts make naphyne and naphdiyne potential candidates for a wide variety of membrane separations and for fabrication of soft and strain-tunable nanoelectronic devices.

Environmental photocatlytsis has been considered as a promising alternative strategy to address the current environmental threats and pressures. Fabrication of the photocatalysts with high efficiency, stability and bio-safety is the core of photocatalytic applications. Herein, we report a facile approach to synthesize monazite BiPO

Antiperovskite CuNFe3 (CNF) thin films have been successfully prepared by chemical solution deposition (CSD) for the first time. They are versatile in many applications as an iron-based nitride. The preparation of pure CNF thin films is a challenging work for the complexity of the phase diagram. Herein, the CNF thin films are phase-pure and polycrystalline. Annealing temperature effects on the microstructures and physical properties were investigated, showing that the CNF thin films are metallic and can be considered as a candidate for room temperature soft-magnets with a large saturated magnetization (Ms) and a low coercive field (Hc). At high temperatures, the electrical transport behavior of CNF thin films presents a low temperature coefficient of resistivity (TCR) value, while the electron&ndash, electron interaction is prominent at low temperatures. The reported solution methods of CNF thin films will enable extensive fundamental investigation of the microstructures and properties as well as provide an effective route to prepare other antiperovskite transition-metal nitride thin films.

Effective utilization of photogenerated electrons and holes in a system is always a research hotspot. Photocatalysis has been identified as a promising solution to tackle the current environmental and energy issues. However, photogenerated holes or electrons were wasted in the traditional photocatalytic process. In the paper, a dual-function photocatalytic reaction system was constructed using dispersed Ptx-modified 2D-3D Zn3In2S6 hierarchical structures (x = 1–4). In the system, aromatic alcohols were photocatalytically selectively oxidated into aldehydes and protons were reduced to hydrogen by photogenerated holes and electrons, respectively. In the reaction process, one aromatic alcohol is first dehydrogenated into aromatic aldehyde and two H+ via the corresponding carbon-centered radical by consuming of two holes, and then two H+ ions dehydrogenated from OH group and α C H of alcohol are evolved into H2 by depleting of two electrons. Atomically dispersed Ptx could offer the maximum atom efficiency and significantly promote visible light absorption and separation of photogenerated electron-hole pairs. The cooperative photoredox system exhibits remarkable photocatalytic activity for visible light-driven splitting of aromatic alcohols. Under visible light irradiation for 6 h, The H2 output over 2.14% Pt/Zn3In2S6 reaches up to 950 μmol, which is around 7.5, 5.3 and 3.8 times higher than that over Zn3In2S6, Pt-nanoparticle/Zn3In2S6 and MoS2/Zn3In2S6, respectively. The apparent quantum efficiency (AQE) of 2.14% Pt/Zn3In2S6 at 400 nm is about 4.6%. The utilization rate of photogenerated electrons to holes could be achieved 98.2%. Moreover, Pt/Zn3In2S6 hybrid shows high stability even when Zn3In2S6 was stored for 12 months. Compared with two half-reactions: the photocatalytic selective organics transformation under O2 atmosphere and the water splitting with sacrificial reagents, such designed dual-purpose photocatalytic reaction not only could effective use of photogenerated electrons and holes for organics transformation and hydrogen production simultaneously but also shows much higher photocatalytic activity than two half-reactions. At the same time, the work also expands the research field of photocatalysis, such as N2 fixation and CO2 reduction by using of the as-produced H+.

Photocatalytic selective organic transformations (SOTs) with sunlight offer a “green” route for synthesis of fine chemicals. In this work, a bare ternary chalcogenide CdLa2S4 photocatalyst was fabricated to couple the selective oxidation (SO) of aromatic alcohols to aldehydes and selective reduction (SR) of nitroarenes to anilines in one reaction system. The photocatalyst showed a high stability and a good generality for the conversions due to the well–matched band structure and the high separation efficiency of photoinduced electrons (e–) and holes (h+). For p–substituted aromatic alcohols, the selectivities to the corresponding aldehydes are as high as ca. 90%. The electro–donating substituent in the para position benefits the SO reactions, which are triggered by h+ via a successive deprotonation; while for p–substituted nitroarenes, the SR to the corresponding anilines is vulnerable to the electro–withdrawing groups and the steric hindrance of the substituent and the selectivities to anilines are substantially lower than that of the SO conversions. H+ deprotonated in the SO of aromatic alcohols is indispensable for the SR of nitroarenes as they are achieved by a H+–coupled six e– reduction process, which leads to the low conversion efficiencies. The half conversions not only be coupled by the photoinduced e– and h+, but also collaborate with each other through H+. Our results clearly demonstrate the emerging concept of a coupled reaction system for sunlight–driven synthesis of fine chemicals and reveal the underlying mechanism.

CdIn2S4, CdS and In2S3 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 In2S3 and CdS samples, CdIn2S4 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 CdIn2S4 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 CdIn2S4 photocatalyst with O2 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.

In the paper, the synthesis of ZnO/TiO2 nanocomposites with different main parts (TiO2 or ZnO) is studied. When TiO2 is the main part of the ZnO/TiO2 heterojunction photocatalysts (ZnO/TiO2), the photocatalytic activity is decreased rapidly with the increase of the amount of ZnO. The reason may be attributed to the relative p–n junction (p-ZnO/n-TiO2) produced between ZnO and TiO2. The migration directions of the electrons and holes in the relative p–n junction are opposite to the transfer directions of the photogenerated electrons and holes in the valence band (VB) and conduction band (CB). However, when ZnO is the primary part of the heterojunction photocatalysts (TiO2/ZnO), the photocatalytic activity of the samples increases with the increase of the TiO2 amount up to 5% (95% ZnO/TiO2). The reason may be that the migration directions of the electrons and holes in the relative p–n junction (p-TiO2/n-ZnO) are the same as the transfer directions of the photoexcited electrons and holes in VB and CB between...

Achieving green synthesis and transformation of organics is always an ambition of scientists under mild conditions. In this paper, a series of CdXZn1−X S (0 ≤ X ≤ 1) samples were synthesized by a simple wet-chemical method using cadmium nitrate, zinc nitrate and sodium sulfide as precursors, and were thoroughly characterized by many techniques, including X-ray diffraction, UV–vis absorption spectra, nitrogen adsorption-desorption isotherms, scanning electron microscopy, transmission electron microscopy and (photo)electrochemical measurements. The photocatalytic performance of the as-prepared samples was evaluated by photocatalytic synthesis of Schiff base compounds in the coupled system of benzyl alcohol and nitrobenzene under visible light irradiation. Results reveal that when X is 0.78 (Cd 0.78Zn0.22 S), the sample exhibits the highest photocatalytic performance. The yield of Schiff base is 55.2% under visible light illumination for 4 h, and the theoretical yields of benzaldehyde and aniline could reach 96.6% and 67.9%, respectively. The quantum efficiency (QE) of the sample with λ = 450 ± 10 nm is 15.8%. In addition, many other Schiff base compounds were also synthesized from the different coupled systems of aromatic alcohols and nitrobenzene. A possible reaction mechanism involving the oxidation of benzyl alcohol to benzaldehyde by photogenerated holes and the reduction of nitrobenzene to aniline by photoinduced electrons, followed by a condensation reaction between benzaldehyde and aniline to generate Schiff base compound was proposed. It is expected that the current work could offer an avenue to fabricate a high-performance photocatalyst used in the fields of photocatalytic selective organic transformations under mild conditions.

In this paper, a simple thermal decomposition synthesis route for a carbon–nitrogen–sulfur (C–N–S) co-doped titanium dioxide (TiO2) mischcrystal with an isobandgap property for visible light applications using urea as the C, and N source and titanium(IV) sulfate [Ti(SO4)2] as S source is reported. The C–N–S co-doped TiO2 mischcrystal exhibited a unique isobandgap characteristic and prominent red-shift in the ultraviolet-visible absorption spectrum and a much narrower band gap (2.42 eV and 1.39 eV) because of defects and impurity levels which were confirmed using powder X-ray diffraction, diffuse reflectance spectroscopy (DRS), photoluminescence, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The excellent photocatalytic performance of the C–N–S co-doped TiO2 mischcrystal samples was demonstrated using degradation of methylene blue and phenol under visible light. The apparent degradation rate of black TiO2 is 4–7 times higher than that of C–N–S co-doped TiO2 (anatase or rutile) under visible light irradiation. The valence band XPS and DRS results were carefully examined to understand the band gap reduction of C–N–S co-doped TiO2. This study confirms that the band gap structure of C–N–S co-doped TiO2 is determined by the mixed crystalline structure and the formation of impurity levels and defective levels. A new idea is presented that will be useful for the design of band gap structure for photocatalysts with higher photocatalytic activities under visible light irradiation.

The use of solar energy to drive organic reactions under mild conditions provides a sustainable pathway for green synthesis and has been one of the primary goals pursued by scientists. In this research, the cadmium indium sulfide (CdIn2S4) photocatalyst was prepared using a simple solvothermal method and was thoroughly characterized using X-ray powder diffraction, UV-visible absorption spectra, nitrogen adsorption-desorption isotherms, scanning electron microscopy, transmission electron microscopy and X-ray spectroscopy measurements. The photocatalytic performance of the CdIn2S4 photocatalyst was evaluated using photocatalytic synthesis of Schiff base compounds in a coupled system of aromatic alcohols and nitrobenzene under visible light irradiation. The yield of N-benzylideneaniline reached up to 32% in the coupled system of benzyl alcohol and nitrobenzene under visible light illumination for 8 h. Furthermore, the changes for the amounts of aromatic aldehydes and AL as intermediate products during the photocatalytic process were also investigated. Using isotopic tracing, a possible reaction mechanism for the photocatalytic synthesis of N-benzylideneaniline and the redox reactions in the coupled system of benzyl alcohol and nitrobenzene was proposed. It is hoped that this strategy can provide an effective pathway for the traditional organic synthesis and transformation using photocatalytic technology under mild conditions.

Photocatalytic selective organic transformation using photoexcited holes and electrons has attracted worldwide interest. Although extensive studies have made significant progress in dehydrogenation of alcohols, hydrogenolysis of alcohols using photoexcited electrons directly constitutes a challenge. Here, photocatalytic selective dehydrogenation and hydrogenolysis of aromatic alcohols into corresponding alkanes/ethers and aldehydes has been achieved by direct use of photoexcited electrons and holes over CdS under visible light irradiation. Compared with other popular visible-light-driven photocatalysts, Sb 2 S 3 , Bi 2 O 3 , N-doped TiO 2 , Zn 3 In 2 S 6 , g-C 3 N 4 , and Ce 2 S 3 , the sum of the yields of alkanes and aldehydes over the as-prepared CdS could reach up to 94% after reaction for 4 h. The high photoactivity and stability of CdS toward dehydrogenation and hydrogenolysis of aromatic alcohols can be ascribed to its appropriate band potentials and effective charge separation–transportation. The optimum positions are that the valence band position should be located between oxidation potentials of alcohol/aldehyde and aldehyde/oxidized aldehyde, and the conduction band position should be more slightly negative than reduction potential of alkane/alcohol. During this reaction, the dehydrogenation reaction consumes two holes and produces two protons; the hydrogenolysis process depletes two electrons and two protons. Therefore, a cooperative, cyclical, and efficient reaction system was established.

Selective oxidation of aromatic alcohols to corresponding carbonyl compounds under mild conditions has a promising prospect in industry. In the paper, we successfully prepared a new mode of photothermocatalyst, Zn3In2S6@ZnO composite, which shows dramatically enhanced activity for selective oxidation of benzyl alcohol to benzaldehyde compared with single Zn3In2S6 and ZnO under visible light illumination. The enhancement is due to a synergistic effect of low-temperature thermocatalysis on ZnO and photocatalysis on Zn3In2S6. ZnO could weaken bonds of the C Hα and the O H. Then the reactive species ( O2− and h+) generated on Zn3In2S6 could be easy for selective oxidation of benzyl alcohol to produce benzaldehyde. The photoelectrochemical and photoluminescence (PL) results and a series of control experiments (e.g. reaction temperature and radical scavenger) prove this synergistic effect and proposed mechanism. Moreover, the stable performance and high activity of Zn3In2S6@ZnO for other aromatic alcohols indicate its applicable potential. This study provides a promising way to combine photocatalysis and thermocatalysis for the design of novel and efficient visible-light-driven catalyst for selective oxidation of aromatic alcohols or other organics under mild reaction conditions.

KNbO 3 /Bi 2 O 3 composite materials with different percentage of KNbO 3 have been prepared by simple methods The structural and optical properties of the resulting samples are thoroughly characterized by XRD, UV–vis DRS, SEM, TEM, and N 2 -sorption analysis. The photocatalytic activities of the as-prepared materials for the degradation of rhodamine B (RhB) and methyl orange (MO) are evaluated under UV-light irradiation. The results indicate that the optimal loading amount of KNbO 3 is 30 wt.% (i. e., 30 wt.% KNbO 3 /Bi 2 O 3 ), The rate constants of which for the RhB and MO degradation are about 3.7 times and 4.1 times faster than those of pure Bi 2 O 3 and approximately 6.9 times and 7.1 times faster than those of pure KNbO 3 , respectively. Based on a series of characterizations, it can be concluded that the migration of photogenerated carriers adopts a direct Z-scheme mechanism and O 2− , OH, and h + are the main reactive species in the photocatalytic reactions.

A phosphate based composite ceramics system, (1 − x)SrZn2(PO4)2–xTiO2 (0 ≤ x ≤ 0.5), was prepared by the solid-state reaction method, and the relations between the phase composition, crystal structure and microwave dielectric properties were investigated. The results show that only two phases of SrZn2(PO4)2 and TiO2 can be obtained in the whole range of x value, and high relative density can be archived for all compositions as suitable sintering temperatures were applied. In the variation process of phase composition ratio, lower increase of dielectric constant value (

MoSx was successfully loaded on hexagonal CdS nanorods as a cocatalyst for the photocatalytic H2 evolution reaction (HER) by a convenient in situ photodeposition method with (NH4)2MoS4 as a precursor. The route is more effective to improve the activity of CdS than the conventional deposition methods. The optimal loading amount of MoSx was determined to be 0.2% (wt%, calculated in terms of MoS2) and the activity of the resulting sample is even higher than that of 0.2% Pt/CdS prepared by a similar photodeposition procedure. An intimate junction in the form of the Cd–S–Mo bond was suggested to account for the high HER performance. This finding opens a new avenue for the deposition and application of sulfide-based cocatalysts which have a great potential to replace noble metal cocatalysts for the photocatalytic HER.

Controlled synthesis of Sn-based oxides with a different valence state is still a challenge. Here, we developed a facile hydrothermal method for selective preparation of SnO2, Sn2+ doped SnO2 (Sn2+–SnO2), and SnO/SnO2 composites, and SnO with SnCl2 as a precursor. The valence state of Sn was regulated successively from Sn4+ to Sn2+ through controlling the hydrothermal solution from an O2-rich to an O2-deficient atmosphere, which was achieved by adding H2O2 or urea into the solution. The structure, absorption, morphology, and the visible light photocatalytic performance of the products were investigated systematically. SnO2, Sn2+–SnO2, SnO/SnO2, and SnO could be prepared in a H2O2-contained, H2O, urea-contained, and N2 purged urea-contained solution, respectively. For Sn2+–SnO2, the doping amount of Sn2+ could be further tuned by varying the hydrothermal temperature, while for SnO/SnO2, the coupling amount of SnO could be controlled by the dosage of urea. Visible-light-induced photocatalytic degradation of methyl orange was achieved successfully on Sn2+–SnO2 and SnO/SnO2. However, further work is still required to improve the stability of the samples due to vulnerability of Sn2+.

In this work, we report a facile and bioinspired synthesis of mesoporous indium sulfide nanoparticles with flowerlike structures controlled by amino acids. During the synthesis procedure, indium sulfide precipitate was prepared by a simple solvothermal method with different amino acids as the directing and assembling agent. The resulting photocatalyst was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflection spectroscopy (DRS), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) specific surface area, electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS). Depending on different amino acids as the crystallization modifiers, the indium sulfide samples exhibit different morphologies. The photocatalytic test of selective oxidation of aromatic alcohols to aromatic aldehydes under visible light irradiation shows that indium sulfide nanoparticles synthesized with addition of amino acids exhibit an increased photoactivity compared to that of In2S3 nanocatalyst without amino acids, which can be attributed to both the relatively high BET surface area and effective separation of photogenerated charge carriers. The effect of various radical scavengers is also investigated. ˙O2− radicals and holes are the main reactive species for photocatalytic oxidation of benzyl alcohol (BA) to benzaldehyde (BAD).

A series of novel CdS/CdIn

A series of ternary chalcogenides, zinc indium sulphide (ZnIn 2 S 4 ), were synthesized by a simple solvothermal method with different solvents. The structure, textural, and optical properties of the resulting materials were thoroughly characterized by several techniques. The as-prepared ZnIn 2 S 4 samples could all be employed as excellent photocatalysts to activate O 2 for selective oxidation of aromatic alcohols to aromatic aldehydes under visible light illumination. The results showed that ZnIn 2 S 4 prepared in ethanol solvent (ZIS-EtOH) exhibited the highest photocatalytic activity among the screened samples. The differences of photocatalytic performance for ZnIn 2 S 4 samples prepared in different media were mainly attributed to the different levels of exposed {0001} special facets caused by the exposure extent of the basic crystal plane. In addition, O 2 − and positive holes were proved to be the main active species during the photocatalytic process. Combined with the previous reports, a possible photocatalytic mechanism for the selective oxidation of benzyl alcohol to benzaldehyde over ZnIn 2 S 4 sample was proposed.

BN/metal sulfide composite (BN/In 2 S 3 ) was prepared by a facile in situ one-pot hydrothermal method. The as-synthesized photocatalyst was characterized by X-ray powder diffraction (XRD), UV–vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 -sorption analysis, electron spin resonance (ESR), photoluminescence emission spectra (PL) and X-ray photoelectron spectroscopy (XPS). The results show that compared with single In 2 S 3 , the BN/In 2 S 3 photocatalyst exhibits excellent photocatalytic performance for selective oxidation of aromatic alcohols to aromatic aldehydes under visible light irradiation. The enhanced photocatalytic activity of BN/In 2 S 3 composite is mainly attributed to the unique physicochemical properties of BN nanosheet, which acts as a promoter for photoexcited holes transfer, thereby improving the charge separation efficiency and prolonging photoexcited electrons lifetime. Effects of the type of aromatic alcohol and the added scavenger on the photocatalytic efficiency were also investigated. O 2 − radicals and photogenerated holes play decisive roles for photocatalytic oxidation of aromatic alcohols to aromatic aldehydes. This approach is versatile for constructing other high efficiency photocatalysts such as BN/CdS, BN/Cd x Zn 1-x S and BN/ZnIn 2 S 4 . It is hoped that this work could provide new insights to construct the BN-based composites for extensive photocatalytic applications.

In this study, a nanoparticle structure of CdS with cubic phase (CdS-G) was prepared by a facile solid-state reaction at room temperature for the first time. CdS-G can be used as a highly active photocatalyst for selective oxidation of p-methoxybenzyl alcohol (pMBA) to p-methoxybenzaldehyde (pMBAD) and reduction of nitrobenzene (NB) to aniline (AL) in a coupled reaction system under green mild reaction conditions through visible light irradiation. Compared with the counterparts prepared by the conventional precipitation method (CdS-P) and hydrothermal method (CdS-H), the photocatalytic performance of CdS-G is greatly improved owing to the unique features of the nanostructure, the high surface area, pore volume, visible light absorption and photoelectric properties. The yield of pMBAD (AL) over CdS-G is about 1.6 (5.2) and 1.9 (20.8) times higher than that over CdS-P and CdS-H, respectively. The CdS-G sample exhibits excellent selectivity and stability because its valence band (VB) and conduction band (CB) positions matched well with the redox potentials of pMBA/pMBAD and NB/AL. Furthermore, the photogenerated holes and electrons can be efficiently and directly reacted with pMBA and NB, respectively. The photocatalytic selective oxidation and reduction reaction is a synergistic reaction via producing and consuming protons. The photogenerated holes and electrons could be utilized thoroughly to produce pMBAD and AL, respectively. The molar ratio of pMBA and NB was 3 : 1, and the yield of pMBAD and AL could be successfully achieved at a theoretical ratio of 1 : 1. This work highlights the promising scope for selective organic synthesis in one reaction system under mild conditions using photogenerated electrons and holes directly and simultaneously.

Li-doped TiO2/SO42− nanoparticles was successfully synthesized via a simple calcinination process in a vacuum environment using Ti(SO4)2 and LiBr as precursors, and were characterized by TEM, XRD, IR, DLS, XPS and UV-vis (DRS). Li doping can reduce the diameters of TiO2 nanoparticles and affect the surface chemical forms and structures. The as-prepared photocatalysts with different LiBr contents exhibited a notably enhanced degradation efficiency for methylene blue, and exhibited the highest photocatalytic activity under UV light when the molar doping ratio of Li was 0.0125. Moreover, the most photocatalytically efficient sample also showed much higher activity for eliminating methylene blue under visible light (380 < λ < 700 nm) by applying a negative bias than P25 and the control samples without applying a negative bias. The introduced negative bias electrostatic fields could not only render TiO2 responsive to visible light, but was also able to increase the lifetime of the photo-excited charges in the doped semiconductor. This provides a facile, fast and universal method to rapidly degrade organic materials based on the Franz–Keldysh effect and the synergetic effects of the electrostatic force.

Hollow copper monosulfide (CuS) nanospheres were synthesized by using copper(I) oxide nanoaggregates as sacrificial templates with thioacetamide in the absence of surfactants by a one-pot method. The hollow CuS nanospheres that are ∼100 nm in diameter with a clean surface were obtained via Kirkendall effect. These hollow nanospheres were well characterized and used as catalysts for the degradation of Rhodamine B and methylene blue with hydrogen dioxide. It was revealed by the catalytic results that these CuS nanospheres were highly efficient catalysts for dye degradation in the darkness, possibly due to the hollow structure and clean surface.

Environmental photocatlytsis has been considered as a promising alternative strategy to address the current environmental threats and pressures. Fabrication of the photocatalysts with high efficiency, stability and bio-safety is the core of photocatalytic applications. Herein, we report a facile approach to synthesize monazite BiPO4 (SHTW) with high crystallization and hydroxylation. The wide bandgap of the SHTW can provide strong redox abilities to produce reactive species and mineralize organic pollutants. Its high crystallinity and dipole moment can promote separation and transportation of the photoexcited electron-hole pairs effectively. In addition, the hydroxylation can produce more highly oxidizing hydroxyl radicals and further improve charge carrier separation. Notably, the hydroxylation can be reborn and the high crystallization can be maintained during photocatalysis. Thus, a virtuous cycle can be established and organic pollutants can be removed efficiently. The mineralization rate of 146.1 μmol g−1 h−1 can be obtained on the SHTW for photocatalytic degradation of benzene, which is about 8.5 times higher than that of the commercial TiO2 (P25). Various dyes, dyes mixture and bisphenol A can all be completely degraded over the SHTW. It shows the potential application and value in environmental governance.

In this study, a new photocatalytic reaction system for simultaneous selective oxidation of aromatic alcohols to corresponding aldehydes and reduction of protons to H

The structure, composition, and electronic property of mixed-cation borohydrides are of significant importance for understanding and improving their thermodynamic and kinetic activities. Conventional density functional theory (DFT) fails to correctly describe the electronic structure of the system due to insufficient cancellation of the self-interaction energy and underestimation of the band gap. In the present work, we present a systematic investigation of the structural and electronic properties of KY(BH

The use of solar energy to drive organic reactions under mild conditions provides a sustainable pathway for green synthesis and has been one of the primary goals pursued by scientists. In this research, the cadmium indium sulfide (CdIn2S4) photocatalyst was prepared using a simple solvothermal method and was thoroughly characterized using X-ray powder diffraction, UV-visible absorption spectra, nitrogen adsorption-desorption isotherms, scanning electron microscopy, transmission electron microscopy and X-ray spectroscopy measurements. The photocatalytic performance of the CdIn2S4 photocatalyst was evaluated using photocatalytic synthesis of Schiff base compounds in a coupled system of aromatic alcohols and nitrobenzene under visible light irradiation. The yield of N-benzylideneaniline reached up to 32% in the coupled system of benzyl alcohol and nitrobenzene under visible light illumination for 8 h. Furthermore, the changes for the amounts of aromatic aldehydes and AL as intermediate products during the photocatalytic process were also investigated. Using isotopic tracing, a possible reaction mechanism for the photocatalytic synthesis of N-benzylideneaniline and the redox reactions in the coupled system of benzyl alcohol and nitrobenzene was proposed. It is hoped that this strategy can provide an effective pathway for the traditional organic synthesis and transformation using photocatalytic technology under mild conditions.

Graphitic carbon nitride can be imprinted with a twisted hexagonal rod-like morphology by a nanocasting technique using chiral silicon dioxides as templates. The helical nanoarchitectures promote charge separation and mass transfer of carbon nitride semiconductors, enabling it to act as a more efficient photocatalyst for water splitting and CO2 reduction than the pristine carbon nitride polymer. This is to our knowledge a unique example of chiral graphitic carbon nitride that features both left- and right-handed helical nanostructures and exhibits unique optical activity to circularly polarized light at the semiconductor absorption edge as well as photoredox activity for solar-to-chemical conversion. Such helical nanostructured polymeric semiconductors are envisaged to hold great promise for a range of applications that rely on such semiconductor properties as well as chirality for photocatalysis, asymmetric catalysis, chiral recognition, nanotechnology, and chemical sensing.

Fe-g-C3N4 (denoted as Fe-CN) and titanium silicate zeolite (TS-1) hybrid materials were fabricated by a facial thermal polymerization approach using dicyandiamide, metal chloride as precursors and TS-1 zeolite as a support. The structure and textural properties of the resulting hybrid materials were thoroughly characterized by X-ray diffraction, UV–Vis spectrophotometry, nitrogen adsorption–desorption isotherm, Fourier transform infrared spectroscopy, scanning transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurement. The as-synthesized Fe-CN/TS-1 composites could be used as heterogeneous catalysts for the photocatalytic selective oxidation of benzene to phenol using H2O2 as benign oxidant under ambient conditions. It is found that the Fe-CN/TS-1 hybrid materials show superior photocatalytic performance for the phenol production from benzene to sole Fe-CN and TS-1 catalysts. Under the optimal conditions, up to 10.0% phenol yield (based on benzene) is achieved over the hybrid materials, with 18.4% phenol selectivity (based on H2O2).

A polymeric Fc-CO-NH-C3N4 (Fc-CN) material was synthesized by amidation reaction of ferrocenecarboxylic acid (Fc-COOH) with NH2 groups on the surface of mesoporous graphitic carbon nitride (MCN). The properties of the as-synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, UV-Vis diffuse reflectance spectra, N2 adsorption-desorption isotherm, photoluminescence spectroscopy, transmission electron microscopy, electron paramagnetic resonance, (photo)electrochemical measurement and X-ray photoelectron spectroscopy. The resultant catalysts were investigated as heterogeneous catalysts for the selective oxidation of benzene to phenol using H2O2 as a green oxidant under visible light irradiation. The results reveal that Fc-modified samples can not only extend the visible light absorption, but also accelerate the bulk-to-surface charge transfer and separation via surface dyadic structures, both of which are favorable for phenol production from benzene photocatalytic hydroxylation with H2O2. Under the optimal conditions, up to 16.9 % phenol yield (based on benzene) is obtained by Fc-CN/1.5-5 sample, and the corresponding Fe content is about 0.64 wt%. Furthermore, after the second run, no significant decrease of the activity (in term of TOF) and the selectivity is found in Fc-CN/1.0-5 sample. Combined with the experimental results and Fenton-chemistry, a possible photocatalytic reaction mechanism on the hydroxylation of benzene to phenol at neutral medium with visible light is proposed.

Ferrocene moieties were heterogenized onto carbon nitride polymers by a covalent -C=N- linkage bridging the two conjugation systems, enabling the merging of the redox function of ferrocene with carbon nitride photocatalysis to construct a heterogeneous Photo-Fenton system for green organocatalysis at neutral conditions. The synergistic donor-acceptor interaction between the carbon nitride matrix and ferrocene group, improved exciton splitting, and coupled photocatalytic performance allowed the direct synthesis of phenol from benzene in the presence of H2 O2 under visible light irradiation. This innovative modification method will offer an avenue to construct functionalized two-dimensional polymers useful also for other green synthesis processes using solar irradiation.