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An efficient Ni 2 P–CdS photocatalyst for photocatalytic hydrogen evolution was synthesized by phosphorizing β-Ni(OH) 2 nanosheet with exposed (001) facets on CdS nanorods. The obtained Ni 2 P–CdS composite displays an outstanding and stable photocatalytic hydrogen generation rate of 68.47 mmol g−1 h−1 in 10 vol% lactic acid under visible light irradiation, more than 17 times higher than that for pure CdS nanorods. The transient photocurrent response, EIS measurement, Mott-Schottky plots, acidic LSV measurement, and PL spectra have proved that Ni 2 P loading can significantly improve the separation of photo-excited electron-hole pairs in CdS nanorods and enhance the hydrogen evolution capability for CdS. These improvements are achieved by features of Ni 2 P such as the high capability of trapping photo-generated electrons from CdS, lifting the total Fermi level and lowering the hydrogen evolution overpotential of the composite. The results show that β-Ni(OH) 2 precursor with a high exposure degree of (001) facet is contributed to the epitaxial formation of (001)-facet-exposed Ni 2 P co-catalyst on CdS nanorods, resulting in that the Fermi level and the hydrogen evolution overpotential of the composite can be further lifted and lowered. This study has provided a novel precursor-derived route to fabricate high-performance co-catalysts with highly exposed active facets on CdS nanorods for effective photocatalytic hydrogen evolution. • Ultrathin β-Ni(OH) 2 nanosheet precursor is employed in fabricating Ni 2 P on CdS. • β-Ni(OH) 2 nanosheet with exposed (001) facet facilitate Ni 2 P(001) growth on CdS. • Hydrogen evolution and charge separation of CdS can be markedly improved by Ni 2 P. [ABSTRACT FROM AUTHOR]

A Cu 2 O/(001)TiO 2 @Ti 3 C 2 T x photocatalyst was synthesized via a wet-chemistry reduction method by N, N-dimethylformamide (DMF). By scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), it was revealed that the surface coverage of photocatalyst increased with the loading amount of Cu 2 O, while the particle size of Cu 2 O did not change significantly. The photocatalytic activity and mechanism of ternary Cu 2 O/(001)TiO 2 @Ti 3 C 2 T x photocatalyst heavily depend on the surface coverage of copper species. When the surface coverage of photocatalyst by Cu 2 O was low, the Ti 3 C 2 T x acted as hole reservoir. Cu 2 O was firstly reduced in situ to metallic copper by excited electrons. Then the reverse movement of carriers enabled the spatial separation of photogenerated electron-hole pairs, and afforded relatively high hydrogen evolution (more than 1100 μmol h−1 (g CuO x TiO 2)−1). When the coverage of Cu 2 O on (001)TiO 2 @Ti 3 C 2 T x was too high at high loading amounts, Ti 3 C 2 T x failed to play the role of hole trapping. Under that circumstance, the photocatalytic reaction follows p-n junction mechanism, leading to low hydrogen productivity. The results here shed light on the relationship between structure and activity of Cu 2 O/(001)TiO 2 @Ti 3 C 2 T x , which was conducive to the development of the MXene-based photocatalysts. Image 1 • A Cu 2 O–TiO 2 –Ti 3 C 2 T x ternary catalyst fabricated by a solvent reduction method. • The loading amount and surface coverage of Cu 2 O can be easily adjusted. • The hydrogen evolution activity can be manipulated by the amount of copper species. • The photocatalytic reaction mechanism depends on the surface coverage of Cu 2 O. [ABSTRACT FROM AUTHOR]

Abstract: The influence of the electrodeposition potential on the morphology of Cu2O/TiO2 nanotube arrays (Cu2O/TNA) and their visible-light-driven photocatalytic activity for hydrogen evolution have been investigated for the first time in this work. The photocatalytic hydrogen evolution rate of the as-prepared Cu2O/TNA at the deposition potential of −0.8 V was about 42.4 times that of the pure TNA under visible light irradiation. This work demonstrated a feasible and simple electrodeposition method to fabricate an effective and recyclable visible-light-driven photocatalyst for hydrogen evolution. [Copyright &y& Elsevier]