Efficient encapsulation of CsPbBr3 and Au nanocrystals in mesoporous metal–organic frameworks towards synergetic photocatalytic CO2 reduction

Abstract

The severe photogenerated charge carrier recombination and the poor CO₂ adsorption capacity are regarded as the two main factors impeding the photocatalytic CO₂ reduction performances of metal halide perovskite (PVK) nanomaterials. Herein, a ternary CsPbBr₃/Au/PCN-333(Al) hybrid featuring high CsPbBr₃ nanocrystal loading, fast charge separation, and good CO₂ uptake is designed and fabricated by using Al-based mesoporous metal–organic framework (MOF) particles to encapsulate CsPbBr₃ and Au nanocrystals, for synergetic photocatalytic CO₂ reduction. A vacuum-assisted pore-filling method is developed to facilitate the permeation of CsPbBr₃ precursor solution into PCN-333(Al), which results in a high CsPbBr₃ loading of >40 wt%. Detailed heterostructure and photoelectric property analysis reveal that well-dispersed CsPbBr₃ and Au nanocrystals inside the MOF matrix can form close contact with each other, which can extract the photogenerated electrons of CsPbBr₃ to Au, so as to effectively inhibit the charge recombination and accelerate the CO generation. As a result, the CsPbBr₃/Au/PCN-333(Al) hybrid exhibits a significantly improved CO₂ reduction performance with the photoelectron consumption yield (R_electron) being 11.5-fold higher than that of single CsPbBr₃ nanocrystals and a 100% selectivity for CO. This study demonstrates a new way to design a high-quality PVK/MOF heterostructure catalyst, which may also find application in other photocatalytic reactions.