High C‐Selectivity for Urea Synthesis Through O‐Philic Adsorption to Form *OCO Intermediate on Ti‐MOF Based Electrocatalysts

Abstract

AbstractThe advent of utilizing nitrate (NO3−) for electrochemical co‐reduction with carbon dioxide (CO2) 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 CO2 and NO3−. 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 *NH2 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 CO2 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.