Enhanced H2 evolution of TiO2 with efficient multiple electrons transfer modified by tiny CuOx–NiO bimetallic oxides.

CuO x –NiO bimetallic oxides modified TiO 2 catalysts were prepared via a precipitation-photoreduction approach for photocatalytic H 2 production. 0.9%Cu0.1%Ni/TiO 2 exhibited the highest H 2 evolution rate (about 55.4 μmol/g/min) under UV–visible light irradiation (350–780 nm), which is higher than the sum of CuO x /TiO 2 and NiO/TiO 2 catalyst. Cu species exhibited more reducing valence state including Cu 0 when deposited on NiO/TiO 2 compared with deposited on TiO 2 . The polyvalent Cu species lead to enhanced photocurrent and reduced transfer resistance confirmed by photoelectron chemical analysis. CuO x –NiO modification of the TiO 2 surface is beneficial for the photoexcited electron transfer, which suppresses electrons recombination. The lifetime of photoexcited electrons was enhanced greatly from 1.16 (TiO 2 ) to 5.15 ns (CuO x –NiO/TiO 2 ). A multiple electrons transfer mechanism for polyvalent bimetallic oxides co-modified TiO 2 was proposed based on careful analysis. This work demonstrated a polyvalent bimetallic oxides modified TiO 2 system with efficient photocatalytic H 2 production which can provide some insightful understanding for bimetallic metal oxides co-catalyst design and H 2 evolution mechanism. [ABSTRACT FROM AUTHOR]