Zhang Luming, Ma Huan, Sun Yongfang, Zhao Yilin, Deng Huiying, Wang Yuhang, Wang Fei, Wen Xiao-Dong, Luo Mingchuan
College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, P. R. China.
National Energy Center for Coal to Liquids, Synfuels China Co., Ltd, Huairou District, Beijing, P. R. China.
Nat Commun. 2025 May 30;16(1):5039. doi: 10.1038/s41467-025-60353-9.
Renewable electricity driven CO electroreduction into methane offers a sustainable route to mitigate our dependence on natural gas. However, this route is now limited by the unsatisfied efficiency and short durability, which originates from a kinetic disparity between water dissociation (WD) and proton-coupled electron transfer on existing catalysts. Herein, we harness the exceptional WD capability of the intermetallic electride (IE) materials for the electrocatalytic methanization from CO. Combinative experimental and theoretical approaches strongly evidence a spontaneous WD on an IE LaCuSi catalyst due to its unique electronic structure (strongly modified charge states, reversible lattice hydride ions and anionic electrons). Consequently, this catalyst exhibits improved methanization performance in alkaline flow cells, achieving a methane Faraday efficiency of 72% at -1.21 V versus the reversible hydrogen electrode (vs. RHE) and peak partial current density of 476.7 mA cm at -1.52 V vs. RHE. Energetic calculations further establish the mechanistic link between WD and methanization processes on our catalyst, on which a lowered free energy barrier for the key *CO to *CHO transformation step is observed. This work sheds light on the pivotal role of WD and expands the repertoire of materials for efficient electrocatalytic methanization from CO.
可再生电力驱动的将一氧化碳电还原为甲烷为减轻我们对天然气的依赖提供了一条可持续途径。然而，这条途径目前受到效率不尽人意和耐久性短的限制，这源于现有催化剂上水离解（WD）和质子耦合电子转移之间的动力学差异。在此，我们利用金属间电子化物（IE）材料卓越的水离解能力实现一氧化碳的电催化甲烷化。结合实验和理论方法有力地证明了IE LaCuSi催化剂上由于其独特的电子结构（强烈改变的电荷态、可逆的晶格氢化物离子和阴离子电子）而发生的自发水离解。因此，该催化剂在碱性流动电池中表现出改善的甲烷化性能，在相对于可逆氢电极（vs. RHE）为 -1.21 V时实现了72%的甲烷法拉第效率，在相对于RHE为 -1.52 V时达到了476.7 mA cm的峰值分电流密度。能量计算进一步建立了我们催化剂上水离解和甲烷化过程之间的机理联系，在该催化剂上观察到关键的CO到CHO转化步骤的自由能垒降低。这项工作揭示了水离解的关键作用，并扩展了用于一氧化碳高效电催化甲烷化的材料种类。
