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Tungsten phosphide (WP) as an excellent hydrogen evolution reactions (HER) catalyst has attracted widespread attention, but its HER activity is low in alkaline media due to high water dissociation barrier. Herein, noble-metal-free cocatalyst WP/WO 3 composite was synthesized by adjusting the P/W molar ratio in the raw material using a simple solid phosphidation reaction. The structure, morphology, composition, and optoelectronic properties of the as-synthesized samples were characterized by XRD, SEM, TEM, XPS, UV–vis DRS, PL techniques, and electrochemical methods. Under visible light irradiation (λ ≥ 420 nm), the photocatalytic HER activities of the as-prepared samples using Eosin-Y (EY) dye as a sensitizer and trimethylamine (TMA) as an electron donor were investigated. The result shows that WP/WO 3 composite as a cocatalyst exhibits excellent photocatalytic HER activity and good stability. The highest apparent quantum yield (AQY) reaches 32.8 %. The presence of amorphous WO 3 in crystalline WP can improve the separation efficiency of photogenerated electrons and holes, reduce HER overpotential, and promote the dissociation of H 2 O in alkaline media. Therefore, the photocatalytic HER activity of WP/WO 3 composite is higher than that of single crystalline WP. [Display omitted] • WP/WO 3 composite was prepared by adjusting the P/W molar ratio in the raw material. • WP/WO 3 composite exhibits high dye-sensitized photocatalytic HER activity. • WO 3 coupling with WP promotes the separation of photocarriers and H 2 O dissociation. • The AQY of 32.8 % at 420 nm is achieved under the optimized conditions. [ABSTRACT FROM AUTHOR]

A series of ZIS-x [ZIS and x represent the ZnIn 2 S 4 and the addition amount of TEOA (mmol) in the synthesis process, respectively] were synthesized via a hydrothermal method using triethanolamine (TEOA) as a template. The as-synthesized photocatalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Ultraviolet-visible (UV–vis) diffuse reflection spectroscopy and Brunauer–Emmett–Teller (BET) surface area measurement. The effects of TEOA on the crystal structures, morphologies and optical properties of ZIS-x products were investigated. The photocatalytic activity was tested in the reaction of H 2 evolution from aqueous TEOA solution under visible light irradiation (λ ≥ 420 nm). It was found that the activity of ZIS-x synthesized in TEOA solution was higher than that of ZIS-0 synthesized in pure water. This can be attributed to the facts that ZIS-x is composed of single ZnIn 2 S 4 and more TEOA can be adsorbed on ZIS-x surface, which improves the separation of an electron-hole pair. When TEOA was used as an electron donor, it can enhance notably photocatalytic H 2 evolution with its simultaneous degradation. The effect of TEOA concentration on the H 2 evolution rate is consistent with a Langmuir–Hinshelwood kinetic model. The optimal amount of Pt loaded on the photocatalyst is 0.50 wt%, and the optimal pH for photocatalytic H 2 evolution is 13. On the optimal condition, the rate of hydrogen evolution over ZIS-2.0 is 2 times as high as that of ZIS-0 during 20 h irradiation. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoP/g-C 3 N 4 hybrid photocatalyst was prepared in which CoP acts as a noble-metal-free HER cocatalyst. • CoP/g-C 3 N 4 composite exhibits high dye-sensitized photocatalytic HER activity and stability. • Photogenerated electrons can effectively transfer among EY, g-C 3 N 4 and CoP. • The AQY of 56.3% at 420 nm is achieved under the optimized conditions. In this paper, CoP/g-C 3 N 4 composite photocatalysts were prepared, in which CoP was used as a noble-metal-free cocatalyst. Using dye Eosin Y (EY) as the sensitizer and triethanolamine (TMA) as the electron donor, the performance of the photocatalytic H 2 evolution reaction (HER) under visible light (λ ≥ 420 nm) was investigated. When the loading of CoP is 5 wt%, the CoP(5 wt%)/g-C 3 N 4 composite shows the best photocatalytic HER performance, even better than that of Pt(5 wt%)/g-C 3 N 4. The apparent quantum yield (AQY) achieves 56.3% under 420 nm light irradiation, one of the best values reported for noble-metal-free cocatalysts in the dye-sensitized HER system, and the catalyst also exhibits good stability under 36 h of irradiation. The high activity and stability of CoP(5 wt%)/g-C 3 N 4 are the results of efficient electron transfer among photoexcited EY, g-C 3 N 4 and CoP, and the excellent HER activity of CoP. [ABSTRACT FROM AUTHOR]

All carbon-based CG/M − CN rectangular nanotubes have been constructed by a facile molten salt thermal condensation of melamine and glucose. In the molten salt fluid, the glucose is carbonized into graphene-like (CG) nanosheets acting as an electron acceptor, and the melamine thermally condenses into carbon nitride (M − CN) rectangular nanotube acting as an electron donor. The 0.5 wt% CG/M − CN nanotubes display a photocatalytic H 2 evolution rate of 2345 μmol h−1 g−1, which is 1.52 times higher than that of M-CN. Moreover, without loading Pt co-catalyst, the 0.5 wt% CG/M − CN nanotubes show a 12.75 times higher photocatalytic H 2 evolution rate than that of M-CN. It is revealed that the graphene-like CG nanosheets not only can act as an electron acceptor boosting charge carrier separation, but also function as a HER cocatalyst for M-CN. Our work provides a new insight for the development of all carbon-based photocatalysts for energy-related applications. All carbon-based donor-acceptor (D-A) conjugated CG/M − CN rectangular tubular composites with HER cocatalyst free have been constructed through a facile one-step molten salt thermal condensation approach, which exhibits superior photocatalytic hydrogen evolution performance. [Display omitted] • The CG/M − CN composites are developed by a molten salt thermal condensation method. • CG acts as an electron acceptor and cocatalyst for M − CN to drive H 2 evolution. • The D-A conjugated system promotes fast charge carrier transfer in CG/M-CN. • The 0.5 wt% CG/M − CN without cocatalyst shows optimal photocatalytic performance. [ABSTRACT FROM AUTHOR]

In this work, a noble-metal-free homogeneous system was constructed in one step with Keggin-type polyoxometalate (POM) SiW 12 O 40 4− as a catalyst, Eosin Y as a photosensitizer, and triethanolamine (TEOA) as a sacrificial electron donor for water splitting to produce hydrogen under visible-light irradiation. A two-electron reduced heteropoly blue SiW 12 O 40 6− is produced by photosensitization under visible-light irradiation. The effect of various component concentrations and POMs with different central atoms (PW 12 O 40 3− , GeW 12 O 40 4− , etc.) on hydrogen production was discussed. This simple system made of earth-abundant elements is expected to contribute toward the development of functional and efficient artificial photosynthetic system. [ABSTRACT FROM AUTHOR]