Toward an Understanding of the Enhanced CO<sub>2</sub> Electroreduction in NaCl Electrolyte over CoPc Molecule‐Implanted Graphitic Carbon Nitride Catalyst
Xinyi Tan, Chang Yu, Xuedan Song, Changtai Zhao, Song Cui, Hanyu Xu, Jiangwei Chang, Wei Guo, Zhao Wang, Yuanyang Xie, Jieshan Qiu
Abstract
Abstract Direct CO 2 electrolysis in seawater enables the simultaneous conversion of CO 2 into CO and the chlorine ions into Cl 2 , further meeting downstream industry needs such as phosgene synthesis and also facilitating the net consumption of CO 2 . As a result, the direct implementation of CO 2 electrolysis in seawater is urgently required. Herein, a CoPc molecule‐implanted graphitic carbon nitride nanosheets (CoPc/g‐C 3 N 4 ) electrocatalyst is prepared via a simple mechanochemistry method. The CoPc/g‐C 3 N 4 with a negatively charged surface and preferential adsorption capability for Na + can achieve appreciable faradaic efficiency (FE, 89.5%) toward CO with a current density of 16.0 mA cm −2 in natural seawater and also realize long‐term operation for 25 h in simulated seawater. Process monitoring further reveals that the chlorine ions in NaCl electrolyte can modulate the reaction microenvironment around the anode, which in turn has positive effects on the CO 2 RR in cathode. The CO 2 RR overall splitting in the simulated seawater exhibits a maximum FE of 98.1% towards CO at cell voltage of 3 V. This work describes the development of a carbon‐coupled CoPc molecular catalyst that can drive the CO 2 electrolysis in simulated seawater and provides a promising and energy‐saving coupled reaction system for direct coproduction of CO and Cl 2 .