Mechanism-tailored two-dimensional metal nanosheets for advanced electrocatalytic CO2 reduction: from structural design to practical application

Electrochemical carbon dioxide reduction reaction (CO₂RR) represents a pivotal strategy for sustainable carbon cycling and chemical synthesis. This review comprehensively analyzes the burgeoning field of two-dimensional (2D) metal nanosheets (e.g., Bi, Ag, Co, Pd, Cu) as high-performance electrocatalysts for CO₂RR. We delve into the fundamental catalytic mechanisms underpinning their activity across both gas-phase (e.g., CO, CH₄, C₂H₄) and liquid-phase (e.g., HCOOH, CH₃OH, C₂H₅OH) product formation pathways, with a particular focus on deciphering critical structure-activity relationships. Key intrinsic properties: composition, exposed crystal facets, and defect engineering, are systematically examined to elucidate their profound influence on catalytic activity, selectivity, and product distribution. Beyond mechanistic insights, the review critically assesses the practical utility of these 2D metal catalysts, highlighting emerging applications, persistent challenges (e.g., scalability, long-term stability, competitive reactions, C₂₊ selectivity control), and promising future research trajectories. By bridging fundamental catalytic principles with applied materials design, this work provides novel perspectives for advancing efficient and selective CO₂RR technologies crucial for achieving carbon neutrality goals.