In Situ Photosynthesis of an MAPbI3/CoP Hybrid Heterojunction for Efficient Photocatalytic Hydrogen Evolution

Abstract Halide perovskite like methylammonium lead iodide perovskite (MAPbI 3 ) with its prominent optoelectronic properties has triggered substantial concerns in photocatalytic H 2 evolution. In this work, to attain preferable photocatalytic performance, a MAPbI 3 /cobalt phosphide (CoP) hybrid heterojunction is constructed by a facile in situ photosynthesis approach. Systematic investigations reveal that the CoP nanoparticle can work as co‐catalyst to not only extract photogenerated electrons effectively from MAPbI 3 to improve the photoinduced charge separation, but also facilitate the interfacial catalytic reaction. As a result, the as‐achieved MAPbI 3 /CoP hybrid displays a superior H 2 evolution rate of 785.9 µmol h −1 g −1 in hydroiodic acid solution within 3 h, which is ≈8.0 times higher than that of pristine MAPbI 3 . Furthermore, the H 2 evolution rate of MAPbI 3 /CoP hybrid can reach 2087.5 µmol h −1 g −1 when the photocatalytic reaction time reaches 27 h. This study employs a facile in situ photosynthesis strategy to deposit the metal phosphide co‐catalyst on halide perovskite nanocrystals to conduct photocatalytic H 2 evolution reaction, which may stimulate the intensive investigation of perovskite/co‐catalyst hybrid systems for future photocatalytic applications.