Regulation of product distribution in CO2 hydrogenation by modifying Ni/CeO2 catalysts

• Doping Mn or In in Ni/CeO 2 significantly effects its CO 2 hydrogenation performance. • NiMn(4)/CeO 2 produces mainly CH 4 , while NiIn(4)/CeO 2 gives dominant CO. • Mn promoter enhances Ni reduction and promotes HCOO* and CH 3 * species formation. • Introduction of In hinders Ni reduction and facilitates formation of COOH* species. Conversion of CO 2 into value-added chemicals is a potential way for achieving carbon neutrality. A challenge is to controllably tune its product distribution. Thus, Ni/CeO 2 catalyst is modified here by doping Mn or In by the sol–gel method. NiMn(4)/CeO 2 shows CO 2 conversion of 35.3% and CH 4 selectivity of 86.6%, whereas NiIn(4)/CeO 2 produces dominant CO with selectivity of 99.1% and CO 2 conversion of 23.9%. Such catalytic results are highly comparable to those of previously reported Ni-based catalysts, but loading smaller amounts of Ni (1.7 wt%). Addition of Mn or In in Ni/CeO 2 significantly promotes formation of surface oxygen vacancies, influences Ni reducibility and enhances catalytic stability. Various characterizations, in situ spectroscopy and DFT calculation results reveal that high CH 4 selectivity of NiMn(4)/CeO 2 is due to formation of more HCOO* intermediates, whereas introduction of In significantly promotes formation of COOH* species, but inhibits generation of HCOO*, and thus resulting in dominant CO product.