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Hydrogen Evolution from Water Coupled with the Oxidation of As(III) in a Photocatalytic System

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posted on 2015-12-30, 00:00 authored by Jian-Ping Zou, Dan-Dan Wu, Shao-Kui Bao, Jinming Luo, Xu-Biao Luo, Si-Liang Lei, Hui-Long Liu, Hong-Mei Du, Sheng-Lian Luo, Chak-Tong Au, Steven L. Suib
A series of heterostructured CdS/Sr2(Nb17/18Zn1/18)2O7−δ composites with excellent photocatalytic ability for simultaneous hydrogen evolution and As­(III) oxidation under simulated sunlight were synthesized and characterized. Among them, 30% CdS/Sr2(Nb17/18Zn1/18)2O7−δ (30CSNZO) has the highest in activity, exhibiting a H2 production rate of 1669.1 μmol·h–1·g–1 that is higher than that of many photocatalysts recently reported in the literature. At pH 9, As­(III) is completely oxidized to As­(V) over 30CSNZO in 30 min of irradiation of simulated sunlight. In the photocatalytic system, H2 production rate decreases with the increase of As­(III) concentration, and the recycle experiments show that 30CSNZO exhibits excellent stability, durability, and recyclability for photocatalytic hydrogen evolution and As­(III) oxidation. We propose a mechanism in which superoxide radical (·O2) is the active species for As­(III) oxidation and the oxidation of As­(III) has an effect on hydrogen evolution. For the first time, it is demonstrated that simultaneous hydrogen evolution and arsenite oxidation is possible in a photocatalytic system.

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