Construction of Cu/Mo2C interfaces for tuning product distribution in CO2 hydrogenation to methanol

Two Cu/Mo 2 C catalysts with different interfacial structures are synthesized to reveal how synthesis routes control CO 2 hydrogenation selectivity. • 5Cu/Mo 2 C‑IWI achieves 85.7% methanol selectivity and STY of 53.7 mg MeOH ·g cat −1 ·h −1 , outperforming its doped counterpart that predominantly yields CO and CH 4 . • Moderate metal‑support interaction over catalyst stabilizes Cu δ+ /Mo 6+ for CO 2 conversion to methanol. • In situ DRIFTS verified catalysts follow dual formate-carboxylate pathway, and Cu/Mo 2 C interfacial structure regulates intermediates evolution to determine final product distribution. The conversion of carbon dioxide (CO 2 ) into methanol using renewable energy has dual energy and environmental significance. Molybdenum carbide (Mo 2 C) exhibits excellent CO 2 activation ability and thermal stability, but it is still difficult to achieve high methanol selectivity for catalysts supported on it, and the structure-activity relationship between interface structure and selectivity is still unclear. Here, Cu/Mo 2 C-IWI and Cu@Mo 2 C catalysts were fabricated via incipient wetness impregnation and in situ doping strategies, respectively, to investigate the effect of different Cu/Mo 2 C interfaces on product selectivity. Among them, Cu/Mo 2 C-IWI exhibited high methanol selectivity of 85.7% with a space-time yield of 53.7 mg MeOH ·g cat −1 ·h −1 (230 ℃, 3 MPa), whereas Cu@Mo 2 C predominantly produced CH 4 and CO. Combined X-ray photoelectron spectroscopy and Auger electron spectroscopy results revealed that moderate metal-support interactions in Cu/Mo 2 C-IWI stabilized the higher valence states of Cu δ+ and Mo 6+ species, which are critical for stabilizing formate (HCOO*) and carboxylate (*COOH) intermediates. In contrast, abundant Mo 2+ species and rich oxygen vacancies on Cu@Mo 2 C facilitated the cleavage of C–O bonds, thus promoting CO and CH 4 formation. In situ diffuse reflectance infrared spectroscopy ( in situ DRIFTS) verified that both catalysts follow a dual-path reaction mechanism involving formate and carboxylate intermediates, and interfacial structure dominates the evolution of reaction intermediates and final product distribution. This study establishes a clear correlation among synthesis strategy, interfacial structure and catalytic selectivity, and demonstrates that constructing surface Cu/Mo 2 C interfaces serves as a rational design principle for highly selective hydrogenation of CO 2 to methanol. Download: Download high-res image (210KB) Download: Download full-size image