Interfacial ZnOx/Cu catalyst derived from CuAl2O4 spinel for efficient CO2 hydrogenation to methanol

CuAl 2 O 4 -derived ZnO/Cu catalyst is constructed via reduction-exsolution and H 2 -SMSI • Precise prereduction control creates rich and active ZnO x /Cu interfacial sites • ZnO x /Cu interface promotes H 2 activation, m-HCOO ⁎ pathway and suppresses RWGS • Superior methanol performance originates from enhanced ZnO x /Cu interfacial synergy • The STY of methanol reaches to 525.8 mg CH₃OH ·h −1 ·g cat −1 and selectivity is close to 75.8% Constructing highly exposed Cu/ZnO interfaces represents a crucial strategy for achieving efficient CO 2 hydrogenation to methanol. In this work, CuAl 2 O 4 spinel was employed as the precursor, and an inverse catalyst (oxide/metal, which is a reverse structure to the traditional metal/oxide catalyst) featuring abundant ZnO x /Cu interfacial sites was obtained by combining reduction-exsolution with a hydrogen-induced strong metal–support interaction (SMSI) strategy. Under the reaction conditions of 240 °C and 3.0 MPa, the optimal ZnO/CuAl 2 O 4 –500 exhibits significantly higher methanol selectivity (75.8%) and space-time yield (525.8 mg CH₃OH ·h −1 ·g cat −1 ) compared to the ZnO/CuAl 2 O 4 with negligible ZnO x /Cu interfacial sites. Multiple characterizations combined with theoretical calculations reveal that the strong electronic interaction at the ZnO x /Cu interfacial sites induces the formation of Cu + species and oxygen vacancy (O v )-rich ZnO x . This markedly enhances H 2 activation and spillover, promotes the generation of highly active monodentate formate (m-HCOO ⁎ ) intermediates, and lowers the energy barrier for methanol formation. Concurrently, the interface suppresses the reverse water–gas shift (RWGS) pathway on Cu 0 sites, thereby improving methanol selectivity. This study presents a controllable synthetic strategy for constructing high-performance inverse ZnO x /Cu interfacial sites, providing new insights for the development of efficient catalysts for CO₂ hydrogenation to methanol. In this work, CuAl 2 O 4 spinel was employed as the precursor, and an inverse catalyst featuring abundant ZnO x /Cu interfacial sites was obtained by combining reduction-exsolution with a hydrogen-induced strong metal–support interaction (SMSI) strategy. Under the reaction conditions of 240 °C and 3.0 MPa, the optimal ZnO/CuAl 2 O 4 –500 exhibits significantly higher methanol selectivity (75.8%) and space-time yield (525.8 mg CH₃OH ·h −1 ·g cat −1 ) compared to the ZnO/CuAl 2 O 4 with negligible ZnO x /Cu interfacial sites. Multiple characterizations combined with theoretical calculations reveal that the strong electronic interaction at the ZnO x /Cu interfacial sites induces the formation of Cu + species and oxygen vacancy (Oᵥ)-rich ZnO x . This markedly enhances H 2 activation and spillover, promotes the generation of highly active monodentate formate (m-HCOO ⁎ ) intermediates, and lowers the energy barrier for methanol formation. Concurrently, the interface suppresses the reverse water–gas shift (RWGS) pathway on Cu 0 sites, thereby improving methanol selectivity. Download: Download high-res image (127KB) Download: Download full-size image