Thermal expansion-quench of nickel metal-organic framework into nanosheets for efficient visible light CO2 reduction

Abstract

Metal-organic framework nanosheets (MOF NNs) offer potential opportunities for many applications, but an efficient strategy for the scalable preparation of few-layered two-dimensional (2D) MOF NNs are still a major challenge. Herein, we present an efficient top-down method for the synthesis of the Ni-BDC (Ni2(OH)2(1,4-BDC); 1,4-BDC = 1,4-benzenedicarboxylate) nanosheets utilizing a novel thermal expansion-quench method of the flowerlike bulky MOFs in liquid N2. The obtained Ni-BDC nanosheets exhibit significantly enhanced photocatalytic performance of reductive CO2 deoxygenation (7.0 µmol h−1 mg−1) under visible light illumination compared with the bulky MOFs, due to much higher surface area for CO2 adsorption, more abundant active sites exposed and stronger electron transport ability of the nanosheets. More importantly, this synthetic strategy can be extended to fabricate other MOF nanosheets which also exhibit significantly improved performance for deoxygenative CO2 reduction compared to their bulky counterparts. This work may provide a guideline for preparing other 2D layered photocatalysts materials to realize energy conversion applications.