Optimized Active Structure Configuration of the MOF Derived Cu-based Catalysts via Different Atmospheres for Selective CO2 Hydrogenation

Abstract

Significant progress has been evidenced in the development of the synergistic effect of the various active sites for selective catalyzing CO₂ hydrogenation toward the target product. Unveiling the roles of different active sites is conducive to understanding the structure–activity relationship in complex reactions. In this study, the pretreatment atmosphere plays a pivotal role in modulating active site properties. The optimized Ar-pretreated Cu-UiO-66-Ar catalyst shows a high methanol space–time yield of 733 μmol g_cat.⁻¹h⁻¹ at 200 °C, 3.0 MPa, which is 2.7 times than that of H₂-pretreated Cu-UiO-66-H₂ catalyst (274 μmol g_cat.⁻¹h⁻¹). We revealed the interface (Cu–O–Zr sites) and Cu nanoparticles (Cu–Cu sites) co-play a pivotal role in promoting CO₂ conversion and H₂ dissociation via Cu–Cu sites feeds H* to Cu–O–Zr-anchored CO*/HCO* species. Rational contrast experiments of the in-situ DRIFTS highlight the accelerated elementary steps in the CO₂ conversion process contact with the enhanced catalytic activity. Thus, this work is helpful to advance the understanding of the potential mechanism in a composite cross-reaction network.