Investigations on the effect of Cu2+/Cu1+ redox couples and oxygen vacancies on photocatalytic activity of treated LaNi1-xCuxO3 (x=0.1, 0.4, 0.5)

Perovskite like oxides LaNi1-xCuxO3 (x = 0 1 0 4 0 5) were prepared by means of the citric acid complexing method TPR revealed the incorporation of Cu into the perovskite lattice increased the reducibility of the catalyst After LaNi1-xCuxO3 were pretreated in H-2 for 2 h at certain low temperature the material still retained its perovskite structure and oxygen vacancies were generated in the lattice DRS showed that narrowing of band gap of reduced LaNi1-xCuxO3 was governed by the crystalline structure and the defect in the catalyst In the photocatalytic water splitting experiment 200 and 250 degrees C reduced LaNi0 6Cu0 4O3 200 C reduced LaNi0 5Cu0 5O3 possessed the high and colse catalytic activity XPS showed that the molar ratio of Cu2+/Cu-1 approximate to 1 and lattice oxygen/adsorb oxygen approximate to 0 2 in the catalysts had high catalytic activity According to the outcome of our experiments, we conclude that there is a balance relation either between oxygen vacancies and catalytic activity or between Cu2+/Cu1+ redox couples and catalytic performance of these materials for hydrogen production from photocatalytic water splitting Enhancement of hydrogen yield can be attributed to the small band gap and the lowering the recombination probability for electron hole pairs (C) 2010 Published by Elsevier Ltd on behalf of Professor T Nejat Veziroglu