Harnessing point defects for advanced Cu-based catalysts in electrochemical CO2 reduction

Cu-based electrocatalysts are pivotal for converting CO2 into valuable C2+ products, yet their efficiency, selectivity, and durability remains critical challenges. This review systematically examines point defect engineering, encompassing cationic/anionic vacancies and heteroatom doping as a strategic approach to optimize Cu-based catalysts for electrochemical CO2 reduction (CO2R). Vacancy defects primarily modulate electronic structures to enhance CO2 adsorption and stabilize intermediates, while heteroatom doping tailors active sites and lowers energy barriers for C-C coupling. Crucially, synergistic interactions between vacancies and dopants amplify charge transfer and intermediate stabilization, transcending the limitations of isolated defects. Challenges in defect density control, spatial uniformity, and operational stability are critically discussed. Future research should prioritize operando characterization to resolve dynamic defect behavior, multicomponent defect systems to exploit synergistic effects, and machine learning-driven designs to accelerate catalyst discovery. By integrating mechanistic insights into defect engineering, this work provides a roadmap for developing efficient, selective, and durable Cu-based catalysts, advancing sustainable CO2 utilization to address global energy and environmental imperatives.