Factors influencing the photocatalytic activity of alkali Nb-Ta perovskites for hydrogen production from aqueous methanol solutions

The activity of ATa(0.5)Nb(0.5)O(3) (A: Li, Na or K) photocatalysts for H-2 production has been studied using methanol aqueous solutions. Previous studies showed that photocatalysts with 1:1 combination of Ta and Nb showed greatly improved activity compared to the single-metal oxides. In this work, compositional variations have shown that sodium suits best as alkali counterion for H-2 evolution. Variation of reaction parameters like pH and methanol concentration shows that neutral pH and 10 vol.% methanol lead to the best activity of NaNb0.5Ta0.5O3 perovskite. In addition, a notable increase in the H-2 evolution is observed by the use of Pt as co-catalyst, and the variation of its loading amount has also a great influence on the photocatalytic performance. The highest H-2 production rate is obtained with the NaNb0.5Ta0.5O3 catalyst with 0.125 wt.% of Pt loading under UV irradiation. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.