Design Strategies for Markedly Enhancing Energy Efficiency in Electrocatalytic CO2 Reduction Reaction

Abstract

Electrocatalytic CO2 reduction reaction (CO2RR) offers a promising approach to ameliorate the global warming and energy crisis. On the route to deploying this technology, tremendous efforts have been dedicated to devising remarkable electrocatalysts and electrolysis systems. While the performance indicators of CO2RR such as current density and faradaic efficiency are well developed, the energy efficiency (EE), a guiding metric for industrial implementation and economic feasibility of CO2RR, should merit more deliberation. In this context, our review aims at providing a comprehensive understanding on full-cell EE of CO2RR. Firstly, the fundamental principles towards achieving high EE in CO2RR are presented. Subsequently, recent state-of-the-art strategies for boosting EE was elaborated, with focuses on electrocatalysts and system design to lower cell voltage and increase faradaic efficiency. In particular, the emerging integrated electrolysis is highlighted, where conventional anodic OER with limited value is replaced with other value-added oxidations, affording great promise to enhance EE and economic benefits of CO2RR. Finally, future research opportunities in this rapidly evolving field are outlined. This review would attract considerable attention on full-cell EE of CO2 electroreduction and further inspire investigation into elevating EE at commercial-relevant current density to motivate the scale-up of CO2RR.