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Fe and N Co-Doped Porous Carbon Nanospheres with High Density of Active Sites for Efficient CO₂ Electroreduction

Author:
Chen, Yubin, Zou, Liangliang, Liu, Hong, Chen, Chi, Wang, Qi, Gu, Meng, Yang, Bo, Zou, Zhiqing, Fang, Jianhui, Yang, Hui
Source:
Journal of physical chemistry 2019 v.123 no.27 pp. 16651-16659
ISSN:
1932-7455
Subject:
X-ray absorption spectroscopy, active sites, carbon, carbon dioxide, carbon monoxide, catalysts, catalytic activity, cobalt, desorption, electrochemistry, iron, nanospheres, nitrogen, silica, transmission electron microscopy
Abstract:
To enhance the electrocatalytic performance of transition metal and nitrogen codoped carbon (M–N–C) for the CO₂ electroreduction reaction, we present a Fe and N codoped porous carbon nanosphere (Fe–N–PC) with a high density of single-atom iron active sites and a few Fe clusters, as indicated by high-resolution TEM and EXAFS, using SiO₂ as the protecting shell to restrict isolated Fe atoms and to trap the volatile N-containing species. The Fe doping content can reach as high as 3.9 wt %. The Fe–N–PC catalyst exhibits an excellent performance for converting CO₂ to CO with high Faradaic efficiency (∼90%) and remarkable partial CO current density (11.44 mA cm–²) at −0.49 V. Probing analysis and selective chemical modification reveal that both Fe atom and ortho-C of N atoms play a synergetic role in enhancing CO₂RR activity. DFT calculations reveal that the presence of amorphous Fe clusters can facilitate the desorption of CO from the surface of the catalyst, thus further improving the CO₂RR activity. This work presents a general strategy to synthesize advanced M–N–C material with high density of single atom active sites, which could be used as an efficient electrocatalyst for CO₂RR, ORR et al.
Agid:
6515579