Tuning the CO2 and CO Electroreduction by Rate-Determining and Selectivity-Determining Steps

The renewable electricity-driven CO2 and CO reduction represents a promising approach for reducing the CO2 footprint toward carbon neutrality. Substantial research developments have been achieved in designing catalysts and reaction interfaces for enhanced electrocatalytic activity and selectivity, and the investigation and understanding of the complex reaction mechanisms have also been extensively investigated by both in situ characterizations and theoretical investigations. Although quasi-equilibrium and rate-determining step assumptions are widely used in electrochemical kinetics, the overall reaction rate is generally determined by a series of elementary steps, and the influence of a certain elementary step for the overall reaction rate can be quantified based on the degree of rate control theory. For the complicated reaction networks of CO(2) reduction, not only the rate-determining steps but also the subsequent selectivity-determining steps play critical roles, especially in the product selectivity. In this Perspective, we summarize the strategies that can tune the activity and selectivity of CO(2) reduction based on their impacts on the rate-determining steps and selectivity-determining steps, respectively. In addition, we also describe the coupling of CO2 electroreduction with other (electro)chemical reactions, such as nitrite reduction and methane oxidation, to form value-added products. At the end, the current challenges and opportunities in this field are discussed to inspire further development in the next stage.