The electrochemical CO₂ reduction reaction towards value-added fuel and feedstocks often relies on metal-based catalysts. Organic molecular catalysts, which are more acutely tunable than metal catalysts, are still unable to catalyse CO₂ to hydrocarbons under industrially relevant current densities for long-term operation, and the catalytic mechanism is still elusive. Here we report 3,5-diamino-1,2,4-triazole-based membrane electrode assemblies for CO₂-to-CH₄ conversion with Faradaic efficiency of (52 ± 4)% and turnover frequency of 23,060 h⁻¹ at 250 mA cm⁻². Our mechanistic studies suggest that the CO₂ reduction at the 3,5-diamino-1,2,4-triazole electrode proceeds through the intermediary *CO₂–*COOH–*C(OH)₂–*COH to produce CH₄ due to the spatially distributed active sites and the suitable energy level of the molecular orbitals. A pilot system operated under a total current of 10 A (current density = 123 mA cm⁻²) for 10 h is able to produce CH₄ at a rate of 23.0 mmol h⁻¹.

针对增值燃料和原料的电化学CO ₂还原反应通常依赖于金属基催化剂。有机分子催化剂比金属催化剂具有更灵敏的可调性，但仍无法在工业相关电流密度下长期运行将CO ₂催化为碳氢化合物，且催化机理仍不清楚。在这里，我们报道了基于 3,5-二氨基-1,2,4-三唑的膜电极组件用于 CO ₂转化为 CH ₄ ，法拉第效率为 (52 ± 4)%，周转频率为 23,060 h ^-1 (在 250 ℃) mA cm ^-2 。我们的机理研究表明，3,5-二氨基-1,2,4-三唑电极处的 CO ₂还原通过中间体 *CO ₂ –*COOH–*C(OH) ₂ –*COH 进行，从而产生 CH ₄空间分布的活性位点和分子轨道的合适能级。中试系统在10 A（电流密度=123 mA cm ^-2 ）的总电流下运行10 h能够以23.0 mmol h ^-1的速率产生CH ₄ 。