A leap in Cr catalyst toward CO2 electroreduction

What is it about?

Efficient reduction of CO2 to produce carbon-neutral fuels is essential given the increasing energy demands and the consequences of the associated greenhouse gas emissions. One of the major challenges for the cost-efficient electrocatalytic CO2 reduction is the development of efficient catalytic systems based on earth-abundant elements. Herein, we present a Cr-based complex as a highly active molecular electrocatalyst selective to CO2 to CO reduction in DMF/phenol medium, along with systematic evaluation of catalytic performances and in-depth mechanistic studies on its key intermediates.

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Photo by Markus Spiske on Unsplash

Photo by Markus Spiske on Unsplash

Why is it important?

Rare investigations have been made on the Cr-based molecular catalysts in CO2 reduction, demanding novel design strategies and in-depth mechanistic investigations. Here out catalyst achieves an order of magnitude of improvement in terms of turnover frequency over the reported Cr-based molecular electrocatalyst, at an applied overpotential of only 190 mV. This is a 300-mV decrease in overpotential and thus kinetically superior to the state-of-the-art Cr-based precedents. Such a high performance at this low driving force has been rationalized in our work to the metal-ligand cooperativity that facilitates the stabilization of low-valent intermediates, where the ligand also serves as an efficient electron reservoir. Additionally, detailed electrochemical, spectroscopic and computational studies have been performed to characterize the electronic structures of the key reactive intermediates, including CrII, CrI, Cr0 and Cr0-CO species which were rarely investigated before for the Cr-based molecular electrocatalyst in CO2 reduction.

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