In-situ construction of FAPbBr3-wrapped MoS2 heterostructure for photocatalytic H2 evolution from dehydrogenation of aromatic alcohols

Abstract

Photocatalytic H2 evolution from organics dehydrogenation has sparked tremendous research attention. Metal halide perovskites (MHPs) with unique photoelectrical properties are deemed as a promising new-generation photocatalysts. Here, FAPbBr3-wrapped MoS2 heterostructure photocatalysts are in-situ constructed by an anti-solvent method for photocatalytic dehydrogenation of aromatic alcohols, which realizes a co-production of clean H2 fuel and value-added aldehydes. Experimental characterizations and theoretical calculations disclose that the introduction of MoS2 decreases the size of the FAPbBr3, and forms a built-in electric field in the composite, which synergistically inhibit the electron-hole pairs recombination and enhance the charge separation. Meanwhile, the MoS2 with low hydrogen binding energy provides abundant reduction sites to accelerate the kinetic of H2 evolution. As a consequence, the optimal FAPbBr3/MoS2-7 composite exhibits a H2 evolution rate of 1150 μmol g−1 h−1 and a benzyl aldehyde (BAD) generation rate of 1040 μmol g−1 h−1 under visible light irradiation, which is about 6 times of blank FAPbBr3. The activity is comparable to the reported value of H2 production from photocatalytic haloid acid splitting using MHPs-based catalysts. Electron paramagnetic resonance (EPR) measurement reveals that carbon-centered radical of •CH(OH)Ph is the primary intermediate for the photocatalytic dehydrogenation of aromatic alcohols.