Electrochemical reduction of CO₂ into usable hydrocarbons by multiple proton and electron transfers is hindered by slow kinetics and unfavorable thermodynamics. Experiments have reported a wide range of compounds from organic molecules to metal oxides to be suitable homogenous catalysts that can facilitate the above multi-step reaction. Quantum chemical calculations and certain thermodynamic descriptors help in identifying electrochemical conditions at which catalysts participate in energetically efficient proton and electron transfers [1]. We discuss how Pourbaix diagrams can be useful descriptors to identify several organic molecules and inorganic compounds that electrochemically catalyze the conversion of CO₂ [2-4]. We present our latest results on modeling CO₂ electroreduction on tin oxide catalysts and our prediction of new dopants that result in lower overpotentials than undoped tin oxide [5]. References:

1. Keith, J. A. & Carter, E. A. Theoretical Insights into Pyridinium-Based Photoelectrocatalytic Reduction of CO2. J. Am. Chem. Soc. 134, 7580–7583 (2012).
2. Saravanan, K. & Keith, J. A. Standard redox potentials, pKas, and hydricities of inorganic complexes under electrochemical conditions and implications for CO2 reduction. Dalton Trans. 45, 15336–15341 (2016).
3. Groenenboom, M. C. et al. Structural and Substituent Group Effects on Multielectron Standard Reduction Potentials of Aromatic N-Heterocycles. J. Phys. Chem. A 120, 6888–6894 (2016).
4. Saravanan, K., Gottlieb, E. & Keith, J. A. Nitrogen-doped nanocarbon materials under electroreduction operating conditions and implications for electrocatalysis of CO2. Carbon 111, 859–866 (2017).
5. Saravanan, K., Basdogan, Y., Dean, J. & Keith, J. A. Computational investigation of CO2 electroreduction on tin oxide and predictions of Ti, V, Nb and Zr dopants for improved catalysis. J. Mater. Chem. A (2017). doi:10.1039/C7TA00405B