Efficient and long-term photocatalytic H2 evolution stability enabled by Cs2AgBiBr6/MoS2 in aqueous HBr solution

Lead-free Cs₂AgBiBr₆ (CABB) double perovskite as a new-type photocatalytic material alternative to lead halide perovskites holds promise to implement the solar-H₂ conversion, but the interior recombination of photo-generated carriers and thus low photocatalytic hydrogen evolution reaction (HER) rate of CABB restrict its further industrial applications. Herein, we report the composite fabrication of MoS₂/CABB heterostructure for high-efficiency and durable photocatalytic HER by anchoring non-noble MoS₂ onto CABB via a facile dissolution-recrystallization method. The optimized MoS₂/CABB performs a visible-light HER rate of 87.5 μmol h^?1 g^?1 in aqueous HBr solution, ca. 20-fold compared to that of pure CABB (4.3 μmol h^?1 g^?1), and presents a discontinuous 500-h photocatalytic HER stability with no evident loss. The superb performance of MoS₂/CABB can be ascribed to the kinetics-facilitated heterostructure consisting of stable CABB and MoS₂. This work proposes a facile and versatile tactic to construct a low-cost Cs₂AgBiBr₆-based heterostructure for efficient and long-term photocatalytic HER.