Stable and wide spectrum response Zn3As2/Al2O3 photocatalyst for photocatalytic overall water splitting

Abstract

Constructing highly efficient and durable non-noble-metal photocatalysts with a broad spectral response for promoting sluggish photocatalyticover water splitting reaction is very desirable but still challenging. To realize scalable hydrogen production, an energy conversion efficiency of 10 % and stable photocatalysts with broad light-absorption are required. To this end, a wide spectrum response Zn3As2/Al2O3 has been successfully synthesized by a layer-by-layer coating method as a photocatalyst utilized in the hydrogen evolution reaction (HER) for the first time, which gave the HER rate of 92.5 μmol·g−1·h−1. The HER activity did not decline obviously after three runs. Characterization results and photocatalytic performance confirmed that the Al2O3 layer could protect Zn3As2 from photocorrosion, which exhibited preeminent stability and outstanding photocatalytic performance. In addition, Zn3As2/Al2O3 showed light response extending to ∼1300 nm, and more efficient separation capability of photogenerated charges benefited from the built-in electric field between Al2O3 and Zn3As2, which were verified by UV–Vis–NIR DRS and electrochemical measurements. Our research results may provide a new route of design and construction of stable and efficacious photocatalysts to realize solar energy conversion to hydrogen.