Cobalt Tritolylcarboxy Porphyrin-Carbon Black Composite Bifunctional Electrocatalyst for Nitrate and Carbon Dioxide Electroreduction to Ammonia and Formic/Acetic Acid
Kamal Dhakal, Alankar Kafle, Swatej Sabbarwal, Dili R. Subedi, Mohammad K. Altafi, Alireza Hajiseyedjavadi, Sayan Maiti, Shengqian Ma, Thomas R. Cundari, Francis D’SouzaAbstract
Electrochemical nitrate reduction reaction (NO3RR) and carbon dioxide reduction reactions (CO2RR) can serve as environmental remediation tools for pollution control and thus support a circular economy for sustainability. The electrochemical process relies heavily on electrode materials; thus, developing highly active and efficient electrocatalysts for these reactions in a green and cost-effective way is essential. In this study, we examined cobalt porphyrins with different modifications for electrochemical NO3RR and CO2RR to independently produce ammonia and acetic acid/formic acid. The carboxylic acid group-substituted cobalt tetrakis(p-tolyl) porphyrin showed a high Faradaic efficiency of 94% for ammonia, 33.8% for CH3COOH, and 21.1% for HCOOH at various potentials in a neutral pH (∼7) electrolyte. Computational results suggest enhanced binding of key NO3RR and CO2RR intermediates to the −COOH group-substituted cobalt porphyrin during electrocatalysis.