Environmental and Chemical Engineering Research Unit,University of Oulu,P.O.Box 4300,FI-90014 Oulu,Finland;ELI-ALPS,ELI-HU Non-Profit Ltd.,Dugonics ter 13,6720 Szeged,Hungary;Institute of Physics,University of Szeged,Dóm tér 9,H-6720 Szeged,Hungary;Nano and Molecular Systems Research Unit,University of Oulu,P.O.Box 3000,FI-90014 Oulu,Finland;Optoelectronics and Measurement Techniques Unit,University of Oulu,FI-90570 Oulu,Finland;VTT Technical Research Centre of Finland,FI-90590 Oulu,Finland;Microelectronics Research Unit,University of Oulu,P.O.Box 4500,FI-90014 Oulu,Finland
Abstract:
Metal halide perovskites have emerged as novel and promising photocatalysts for hydrogen generation. Currently, their stability in water is a vital and urgent research question. In this paper a novel approach to stabilize a bismuth halide perovskite (CH3)2NH2]3BiI6] (DA3BiI6) in water using dimethylammonium iodide (DAI) without the assistance of acids or coatings is reported. The DA3BiI6 powder exhibits good stability in DAI solutions for at least two weeks. The concentration of DAI is found as a critical parameter, where the I- ions play the key role in the stabilization. The stability of DA3BiI6 in water is realized via a surface dissolution–recrystallization process. Stabilized DA3BiI6 demonstrates constant photocatalytic properties for visible light-induced photo-oxidation of I- ions and with PtCl4 as a co-catalyst (Pt-DA3BiI6), photocatalytic H2 evolution with a rate of 5.7 μmol⋅h-1 from HI in DAI solution, obtaining an apparent quantum efficiency of 0.83% at 535 nm. This study provides new insights on the stabilization of metal halide perovskites for photocatalysis in aqueous solution.
