Few-layer black phosphorus-on-MAPbI3 for superb visible-light photocatalytic hydrogen evolution from HI splitting

Organic-inorganic perovskites like MAPbI(3) with excellent optoelectric properties have recently gained concerns in photocatalytic HI splitting. However, their achieved hydrogen evolution reaction (HER) rates are still insufficient. Herein, a 2D few-layer black phosphorus (BP) as cocatalyst was anchored on MAPbI(3) via electrostatic coupling. The resultant BP/MAPbI(3) is rather stable in HI solution during the whole photoreaction, yielding a superb HER rate of 3742 mu mol h(-1)g(-1) under visible irradiation, which is two orders of magnitude higher than that of MAPbI(3)-only, far higher than that of MAPbI(3)/Pt and also shows the advanced HER performance among MAPbI(3) based systems. The remarkably boosted HER activity is thoroughly explored by optical/optoelectrochemical measurements, showing that BP can act as an electron promoter to trap electrons derived from MAPbI(3) through a type I heterojunction in the interface. This contributes to a new paradigm for high-efficiency photocatalysts by anchoring non-metal cocatalyst onto MAPbI(3) for solar energy conversion.