2018-Sustainable Industrial Processing Summit
SIPS2018 Volume 2. Amatore Intl. Symp. / on Electrochemistry for Sustainable Development
| Editors: | F. Kongoli, H. Inufasa, M. G. Boutelle , R. Compton, J.-M. Dubois, F. Murad |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2018 |
| Pages: | 216 pages |
| ISBN: | 978-1-987820-84-3 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Selective Reduction of Carbon Dioxide in Water using Earth Abundant Metal and Nitrogen Doped Carbon Electrocatalysts
Kim Daasbjerg1; Xin-Ming Hu1; Jun-Jie Shi1; Steen U. Pedersen1; Troels Skrydstrup1; Halvor H. Hval1;1INTERDISCIPLINARY NANOSCIENCE CENTER, AARHUS UNIVERSITY, Aarhus C, Denmark;
Type of Paper: Regular
Id Paper: 256
Topic: 47
Abstract:
Earth-abundant transition metal (Fe, Co, or Ni) and nitrogen doped porous carbon electrocatalysts (M-N-C) were synthesized for CO<sub>2</sub> valorization from cheap precursors via silica templated pyrolysis. [1] The effect of the material composition and structure (i.e. porosity, nitrogen doping, metal identity, and oxygen functionalization) on the activity for the electrochemical CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) in water was investigated. The activity/selectivity order for CO<sub>2</sub>-to-CO conversion is Ni > Fe >> Co with respect to the metal in M-N-C. Notably, the Ni doped carbon exhibits a high selectivity with a faradaic efficiency of 93% for CO production. The metal free material exhibits a high selectivity but low activity for the CO<sub>2</sub>RR. Tafel analysis shows a change of the rate-determining step as the metal overtakes the role of the nitrogen as the most active site.<br />Recording of X-ray photoelectron spectra and extended X-ray absorption fine structure demonstrates that the metals are atomically dispersed in the carbon matrix, most likely coordinated to four nitrogen atoms and with carbon atoms serving as a second coordination shell. Presumably, the carbon atoms in the second coordination shell affect the CO<sub>2</sub>RR activity, considering that the reactivity order for the central metal in carbon supported metal meso-tetraphenylporphyrin complexes is the opposite. From a better understanding of the relationship between the CO<sub>2</sub>RR activity and the material structure, it becomes possible to rationally design high-performance porous carbon electrocatalysts for CO<sub>2</sub> valorization. [2]