Enhancing electronic metal–support interaction in Cu–ZnO/N-carbon catalysts by generating more pyridinic nitrogen species for efficient CO2 hydrogenation to methanol

Abstract

The catalytic hydrogenation of CO₂ to methanol is a pivotal strategy for carbon neutralization. However, the commonly used Cu-based catalysts are often limited by the activity–stability trade-off and the sluggish kinetics of intermediate conversion in this reaction. Herein, we address these challenges by stabilizing Cu–ZnO nanoparticles on nitrogen-doped ordered mesoporous carbon (NOMC). The optimized N-doped catalyst exhibits superior methanol space-time yield (STY) and selectivity, significantly outperforming its pure carbon-supported counterpart. Electronic structure analyses identify pyridinic nitrogen as the critical anchoring site, which induces a strong electronic metal–support interaction (EMSI) and thereby enhances the electron density at the Cu active centers. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and kinetic studies provide molecular-level evidence that this precise electronic modulation significantly lowers the activation barrier for the rate-determining step (RDS), namely the hydrogenation of stable formate (*HCOO) to methoxy (*CH₃O) species. This mechanism effectively unlocks the kinetic bottleneck, facilitating facile methanol synthesis while suppressing the competing reverse water–gas shift (RWGS) reaction. This work unravels the molecular origin of the N-doping effect and establishes a protocol for designing robust non-oxide-supported catalysts for sustainable C₁ chemistry.