Hierarchical sheet-like Cu/Zn/Al nanocatalysts derived from LDH/MOF composites for CO2 hydrogenation to methanol

Abstract

The CO2 hydrogenation to generate methanol is one of the most promising techniques to turn waste CO2 into useful fuel and chemicals in a sustainable manner. Herein, we have designed several hierarchical sheet-like Cu/Zn/Al nanocatalysts to efficiently produce methanol from CO2 hydrogenation by a rational integration of layered double hydroxide (LDH) nanosheets and metal-organic frameworks (MOF) nanoparticles as double solid precursors. Specifically, the uniform loading of Zn-BTC nanoparticles on CuAl LDH surface was achieved by an in-situ growth method at mild conditions. It was found that the pretreatment of the LDH with acetone could effectively exfoliate the sheet-like structure, increase the specific surface area, and facilitate the immobilization of Zn-BTC nanoparticles, which remarkably improved CO2 hydrogenation performance with respect to methanol selectivity (>90% at 200°C). It was found that both the existence of Zn-BTC and the pretreatment of LDH with acetone significantly reduced CO selectivity by increasing the activation energy (Δ(Ea) up to 20 KJ/mol). Moreover, in-situ DRIFTS study indicates that the promoting effect of ZnO (derived from Zn-BTC) on methanol formation is mainly associated with the formation of a higher amount of *CH3O intermediate rather than *CO and *HCOO species on the catalyst surface.