Highly dispersed NiCoB-modified lead-free double perovskite Cs2AgBiBr6 enhances photocatalytic hydrogen evolution through g-C3N4 assistance

Abstract

Lead-free double halide perovskite Cs2AgBiBr6 is a candidate photocatalytic material to replace toxic lead halide perovskite. In this paper, bimetallic boride NiCoB and Cs2AgBiBr6 were coupled by electrostatic self-assembly for the first time, and g-C3N4 was introduced for in-situ growth. The best NiCoB/Cs2AgBiBr6 and g-C3N4 (NiCoB) /Cs2AgBiBr6 exhibits the excellent photocatalytic hydrogenation rate of 60.65 and 89.68 umol·g−1·h−1 without using any precious metals as promoters, which is superior to original Cs2AgBiBr6. The cycling experiments illustrated that both photocatalysts perform excellent stability in the photocatalytic H2 evolution. The photoelectric analysis showed that NiCoB as a cocatalyst could achieve rapid charge separation, and the introduction of C3N4 in the synthesis process can better disperse the cocatalyst. The formation of type II heterojunction structure between Cs2AgBiBr6 and g-C3N4 (NiCoB), this facilitates the separation and transfer of charge carriers.