Constructing imine groups on the surface of Cu1/Pd(111) as a novel strategy for CO2 hydrogenation to methanol

Abstract

Developing a promising strategy to improve the limited selectivity and activity of traditional Pd–Cu bimetallic catalysts for CO₂ hydrogenation to methanol (CH₃OH) remains a grand challenge. By using density functional theory calculations, we discovered that introducing imine groups on the Cu₁/Pd(111) surface through a condensation reaction of aldehydes and amines is an intriguing approach for simultaneously enhancing the selectivity and activity of Cu₁/Pd(111) for CO₂ hydrogenation to CH₃OH. The imine groups formed by amino reactions with acrolein on the Cu₁/Pd(111) surface (C₃H₄O@NH₂-Cu₁/Pd(111)) improved the turnover frequency (TOF). The imine group optimized the electronic structure of active sites and increased electron transfer to the anti-bonding orbital of CO₂, facilitating the activity of C₃H₄O@NH₂-Cu₁/Pd(111) for CO₂ hydrogenation to CH₃OH. Besides, the inhibition of CO by-products and the low desorption energy of CH₃OH were responsible for the high selectivity of C₃H₄O@NH₂-Cu₁/Pd(111) for CH₃OH. This work advances our understanding of the role of imines in catalysis and provides a new strategy for designing excellent functional group-modified catalysts for the hydrogenation of CO₂ to CH₃OH.