Hetero-site cobalt catalysts for higher alcohols synthesis by CO2 hydrogenation: A review

Synthesis of higher alcohols by CO2 hydrogenation is a promising way to mitigate CO2 emissions, meanwhile producing value-added fuels and chemicals. However, CO2 hydrogenation to higher alcohols is kinetically hin-dered and due to the absence of highly efficient catalysts, its industrial implementation is still limited. Among the catalysts designed for this reaction, Co-based catalysts are widely investigated due to earth-abundance and economic, possessing also relatively high activity and selectivity for this reaction. Considering the nature of the active site, the hetero sites of Co-based catalysts such as Co0-CoO, Co0-Co delta+, and Co2C-NaCo2C are critical for higher alcohol synthesis by CO2 hydrogenation. Thus, in this review, we first introduce the roles of Co0, CoO, Co delta+, and Co2C, as well as strategies to tailor their structure which influences the performance in CO2 hydro-genation. Then, we discuss the strategies to create highly efficient hetero-site Co-based catalysts. Finally, emerging methodologies yet to be explored and future directions to achieve highly efficient hetero-site Co cat-alysts for CO2 hydrogenation to higher alcohols are discussed.