Efficient CO2 electroreduction over pyridinic-N active sites highly exposed on wrinkled porous carbon nanosheets

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 351; pp. 613 - 621
• Main Authors: Li, Hongqiang, Xiao, Nan, Hao, Mingyuan, Song, Xuedan, Wang, Yuwei, Ji, Yongqiang, Liu, Chang, Li, Chen, Guo, Zhen, Zhang, Feng, Qiu, Jieshan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2018
• Subjects: Carbon monoxide; CO2 electroreduction; Coal tar pitch; Nitrogen-doped carbons; Porous carbon nanosheets; CO2 electroreduction; Coal tar pitch; Carbon monoxide; Nitrogen-doped carbons; Porous carbon nanosheets
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2018.06.077

[Display omitted] •Pitch derived N-doped carbons were fabricated by template method and NH3 etching.•Active pyridinic-N highly exposed on the surface of conductive carbon frameworks.•This novel carbon sheets exhibit superior activity in electrocatalytic CO2 reduction.•The synergistic porosity, N-doping and 2D morphology lead to a high performance. The development of an efficient catalyst system for the electrocatalytic reduction of CO2 into highly valuable chemicals is a significant research subject. However, conventional metal electrocatalysts usually suffer from high cost, poor durability and limited accessible active sites. The exploration of high-performance and cost-effective metal-free catalysts with abundant exposed active sites is of urgent and highly desirable for CO2 reduction reaction (CO2RR). Herein, we report a facile yet efficient post-etching strategy to fabricate wrinkled N-doped porous carbon nanosheets (WNCNs) as a promising electrocatalyst for selectively producing CO with high stability. The catalyst exhibits negligible onset overpotential (−0.19 V) for CO production and a maximum Faradaic efficiency (FE) of 84% at an overpotential of −0.49 V. The superior performance is credited to the robust and nanoporous two-dimensional (2D) architecture, which are in favor of fast charge transfer, CO2 adsorption as well as the highly exposure of pyridinic-N active sites. First-principles density functional theory (DFT) calculations confirm that the pyridinic-N can offer favorable binding sites to COOH∗ intermediates and facilitate their subsequent catalytic reduction. This work highlights a new class of low-cost and scalable electrocatalysts for synthetic CO production from CO2 under benign conditions for application.