Chapter 5. Theoretical Approach to Homogeneous Catalytic Reduction of CO2: Mechanistic Understanding to Build New Catalysts

Conversion of CO2 into liquid fuels and value-added fine chemicals has gained much attention in recent years to meet the ever-rising global energy demand and hence develop a sustainable solar fuel economy. This chapter enumerates feasible catalytic routes through which CO2 could be utilized as a C1 feedstock. First, we address CO2 functionalization catalysed by metal-free reagents and electrochemical CO2 reduction mediated by organocatalysts and heterogeneous metal surfaces. Next, the reaction pathways undertaken by homogeneous molecular catalysts are highlighted; in particular, non-noble earth-abundant 3d transition metal-based complexes. At the end, we discuss our recent three case studies on two-electron reduction of CO2, namely, CO2 reductive disproportionation to CO and CO32−, and CO2 hydrogenation to HCOO−/HCOOH. Here, we emphasize how mechanistic insights obtained by computational investigations could provide important guidelines to design tailored CO2 reduction catalysts with higher efficiency and enhanced product selectivity.