Ni3C-Decorated MAPbI3 as Visible-Light Photocatalyst for H2 Evolution from HI Splitting

A stable composite photocatalyst, that is, MAPbI3 decorated with Ni3C, is synthesized by a facile surface charge-promoted self-assembly approach and is demonstrated to be a high-efficiency, stable visible-light photocatalyst for H2 evolution in aqueous MAPbI3-saturated HI solution with H3PO2 as a stabilizer. The optimal 15% Ni3C/MAPbI3 suspension under visible illumination displays the hydrogen evolution reaction (HER) rate of 2362 μmol g–1 h–1, which is approximately 55-fold higher than that of MAPbI3 (43 μmol g–1 h–1) and far superior to that of Pt/MAPbI3 (534 μmol g–1 h–1). In particular, the Ni3C/MAPbI3 photocatalyst is ultrastable, showing no obvious decrease of HER activity in a given HER process, that is, 10 runs, one-month storage, and another 10 runs. The origin of the superior performance is proven to be predominantly attributed to the improved capabilities of charge carrier transfer and separation as well as the massive reactive centers on the surface of MAPbI3 by Ni3C decoration, together with the high stability of the composite in HI solution during the photoreaction.