Indian Association for the Cultivation of Science, India
Metalloenzymes are the best known electrocatalysts for most known chemical transformations. Decades of persistent attempts of mimicking their reactivity (both rate and selectivity) using small molecule analogues have resulted in deeper understanding of the factors that contribute to their efficacy. In particular, enzymes that catalyze transformations that require multiple electrons and protons have been particularly difficult to mimic in homogeneous solutions. With the development of new in situ analytical techniques to probe electrocatalysts (e.g. SERRD-RDE), direct information on the rate limiting steps in electrocatalysis has been obtained and, subsequently, appropriate changes in the design of the catalysts have allowed remarkable enhancements in their electrocatalytic activity. Efficient electrocatalysts for facile and selective reduction of oxygen to water and electrochemical analogues of cytochrome P450 has been discovered which show reactivity and turnover rates similar to those of the native enzyme. The mechanistic investigations have revealed similarities between O2 reduction and CO2 reduction and the designing principles employed to affect efficient O2 reduction can be easily translated to CO2 reduction resulting in some of the best known electrocatalysts for the reduction of CO2 to CO.