Molecular catalysis for utilizing CO₂ in fuel electro-generation and in chemical feedstock

Processes for the conversion of CO₂ to valuable chemicals are highly desired as a result of the increasing CO₂ levels in the atmosphere and the subsequent elevating global temperature. However, CO₂ is thermodynamically and kinetically inert to transformation and, therefore, many efforts were made in the last few decades. Reformation/hydrogenation of CO₂ is widely used as a means to access valuable products such as acetic acids, CH₄, CH₃OH, and CO. The electrochemical reduction of CO₂ using hetero- and homogeneous catalysts recently attracted much attention. In particular, molecular CO₂ reduction catalysts were widely studied using transition-metal complexes modified with various ligands to understand the relationship between various catalytic properties and the coordination spheres above the metal centers. Concurrently, the coupling of CO₂ with various electrophiles under homogeneous conditions is also considered an important approach for recycling CO₂ as a renewable C-1 substrate in the chemical industry. This review summarizes some recent advances in the conversion of CO₂ into valuable chemicals with particular focus on the metal-catalyzed reductive conversion and functionalization of CO₂. Copyright © 2019 by the authors. Licensee MDPI, Basel, Switzerland.