Selective hydrogenation of CO2 to methanol catalyzed by Cu supported on rod-like La2O2CO3

Cu-based catalysts have long been applied to convert CO2 and H-2 into methanol, and their performances are well known to be markedly influenced by the support and promoter. Herein, several Cu-based catalysts supported on lanthanum oxides were fabricated by varying the preparation methods and characterized by XRD, TEM, ICP-AES, N-2 physisorption, N2O chemisorption, CO2 chemisorption, XPS, and CO2-TPD. The results showed that the as-prepared Cu supported on rod-like La2O2CO3 (La2O2CO3-R) exhibited the highest TOFCu, methanol selectivity and yields of methanol for the hydrogenation of CO2 to methanol. Distinct from conventional promoter addition, the local formation of a new type of Cu delta+ species at Cu/La2O2CO3-R interfaces and the original adsorption performance of basic oxides are the two key factors relating to the catalytic performance. Cu supported on La2O2CO3-R with a higher content of Cu delta+ species and a stronger adsorption for CO2 leads to superior catalytic activities. DRIFTS studies revealed that the generation of synergetic basic sites at the interfacial areas can increase the intrinsic activity of Cu-based methanol catalysts by moderately and selectively stabilizing methanol synthesis intermediates. This work provides new insights into CO2 activation over basic oxide-supported Cu catalysts, and the identification of metal-support interactions between Cu and lanthanum oxides is beneficial for the rational design of stable Cu-based catalysts.