High C‐Selectivity for Urea Synthesis Through O‐Philic Adsorption to Form *OCO Intermediate on Ti‐MOF Based Electrocatalysts
Xiaofang Liu, Jie Feng, Xue‐Feng Cheng, Jinchang Zhang, Jinyan Huo, Dongyun Chen, Antonio Marcomini, Youyong Li, Qingfeng Xu, Jianmei Lu
Abstract
Abstract The advent of utilizing nitrate (NO 3 − ) for electrochemical co‐reduction with carbon dioxide (CO 2 ) to effectively synthesize high‐value‐added organic nitrogen compounds has captured the attention of the environmental and energy fields. C─N coupling is a key step during the electrochemical co‐reduction process. An effective strategy to improve the efficiency of synthesis is to explore the optimal reaction pathway and coupling active species. Herein, a p‐type semiconductor nanosphere (Ti‐DHTP) is presented for electrochemical co‐reduction to synthesize urea by combining CO 2 and NO 3 − . At a low voltage of −0.6 V versus RHE, the electrochemical synthesis of urea exhibits 95.5% C‐selectivity and 21.75% Faraday efficiency. Comparative experiments, in situ experiments, and theoretical simulations confirm that a new coupling pathway for the synthesis of urea from * NH 2 and * OCO intermediates become a key step in Ti‐DHTP‐driven C─N coupling. Moreover, the more efficient * OCO intermediate inhibits the generation of large amounts of C‐bearing by‐products. Meanwhile, Ti‐DHTP has difficulty hydrogenating to form * COOH during the reduction of CO 2 leading to the subsequent inability to produce * CO intermediates. This work reveals a new C─N coupling mechanism, which provides a feasible strategy for future research on the electrochemical synthesis of organic nitrogen‐bearing compounds.