Semiconductor heterojunctions for photocatalytic hydrogen production and Cr(VI) Reduction: A review

The efficiency of photocatalysis is mainly determined by effective separation of photogenerated electron and hole. Heterojunction-based photocatalysts allow spatial separation of photogenerated charge carriers at the interface between a semiconductor and a co-catalyst or a secondary semiconductor, leading to effective utilization of those photogenerated charge carriers. The construction of heterojunction-based photocatalysts has been widely recognized and developed in past decades, and the related studies on heterojunction-based photocatalysts for hydrogen production and Cr(VI) reduction have been discussed but rarely reviewed comprehensively and systematically from published literature in the past. The current critical review aims to summarize and draw a whole picture of different heterojunctions for enhancing photocatalytic hydrogen production and Cr(VI) reduction. Heterojunction-based photocatalysts with varied junction types are discussed in terms of their energy band positions and photocatalytic hydrogen production and Cr(VI) reduction efficiencies to inspire the future work on the design, construction, and applications of heterojunction-based semiconductor photocatalysts.