Emerging nanostructured carbon-based non-precious metal electrocatalysts for selective electrochemical CO₂ reduction to CO

The electrochemical carbon dioxide (CO₂) reduction (ECR) represents one of the most promising technologies for CO₂ conversion into value-added feedstock from carbon monoxide (CO) to a variety of hydrocarbons. As the raw material for Fischer-Tropsch synthesis, CO is one of the most desirable ECR products and has recently received extensive research attention. Although noble metal materials, such as Au and Ag, show high selectivity towards conversion of CO₂ to CO, their relative scarcity and high cost seriously limit their practical commercial application. Nanostructured carbon-based non-precious metal electrocatalysts (Nano-CNMs) are of tremendous interest in the field of ECR catalysis due to their tunable structures and electronic properties. Herein, we present an overview of recent progress in the application of Nano-CNMs, mainly including heteroatom-doped carbon, transition metal-heteroatom co-doped carbon, and carbon-based hybrid materials, with emphasis on electrocatalytic conversion of CO₂ to CO. We particularly focus on discussing the structure/composition-performance relationships with regard to the electronic structure, surface properties, doping content, and associated electrocatalytic performance of various Nano-CNMs. We outline the future research directions in the development of high-selectivity ECR electrocatalysts for CO production and the stringent challenges in fundamental research and industrial application.