Triple-phase interface engineering in electrocatalytic CO₂ reduction

Catalytic materials offer multidimensional tunability for catalytic reactions, owing to their multilevel structural features in the condensed state, such as defect types, surface and interface configurations, and wettability. Aimed at maximizing reactive interfaces and enhancing catalytic efficiency, modulating hierarchical phase structures has emerged as a pivotal strategy for performance optimization in catalytic systems. The electrocatalytic CO₂ reduction reaction (eCO₂RR) system, as a typical solid-liquid-gas triple-phase interface reaction, inherently exhibits reaction kinetics and catalytic performance governed by the spatial distribution and dynamic characteristics of the triple-phase interface on catalyst surfaces. Therefore, the regulation of the triple-phase interface to maximize the reaction interface is a potent pathway to enhance the catalytic performance of eCO₂RR. This perspective systematically reviews the evolution from traditional liquid-solid biphasic interfaces to advanced solid-liquid-gas triple-phase interfaces delves into the primary challenges of constructing stable triple-phase interfaces on gas diffusion electrodes within the eCO₂RR system and summarizes the latest advancements in regulating the triple-phase interface by enhancing hydrophobicity. Achieving a fine balance between hydrophobicity and hydrophilicity (i. e. , optimal wettability) is crucial for constructing an efficient triple-phase interface. On one hand, sufficient hydrophobicity is required to prevent excessive electrolyte infiltration; on the other hand, moderate hydrophilicity must be maintained to ensure the supply of reactants/ions from the electrolyte. Their dynamic equilibrium can significantly optimize the triple-phase interface structure, enhance mass transfer of reactants, and improve the effective utilization of catalytic active sites. These insights provide valuable guidelines for designing high-performance triple-phase interfaces in eCO₂RR and other gas-involving electrochemical processes, thereby promoting the development of sustainable energy technologies. 催化材料由于其在凝聚态中所具有的多层次结构特征（如缺陷类型、表面与界面构型和润湿性等），为催化反应提供了多维度的调控空间。其中，精准调控物相结构，是优化催化性能的关键策略，可有效拓展反应界面并提升效率。电催化二氧化碳还原反应（eCO₂RR）作为典型的固-液-气三相界面反应，其反应动力学与性能本质上取决于催化剂表面三相界面的空间分布与动态特性。因此，调控三相界面以最大化反应界面是提升eCO₂RR性能的有效途径。本文系统回顾了从固-液界面到固-液-气三相界面的发展历程，深入探讨了在eCO₂RR体系气体扩散电极上构建稳定三相界面面临的主要挑战，并综述了通过增强疏水性调控三相界面的最新进展。特别指出，实现疏水性与亲水性间的精细平衡（即最佳润湿性）是构建高效三相界面的关键：一方面需保持足够疏水性以抑制电解液过度浸润，另一方面又要维持适度亲水性以保障电解液中反应物/离子供给。二者的动态平衡可显著优化三相界面结构，改善反应物传质并提高催化剂活性位点的有效利用率。本研究不仅为eCO₂RR体系提供了新理论指导，也为其他涉及气体的电化学过程（如电催化水分解、氮气还原）中高效三相界面的设计提供了重要参考，有望推动可持续能源技术发展，助力碳中和目标实现。