Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7706381 | International Journal of Hydrogen Energy | 2018 | 10 Pages |
Abstract
Various transition metals have been incorporated into nitrogen-doped carbon nanotubes (M-N-C/CNT, MÂ =Â Fe, Co, Mn, and Ni) via a one-pot method using dopamine as nitrogen source and metal salts as precursors for oxygen reduction reaction (ORR). Raman spectra and XRD patterns of the catalysts were collected to characterize the graphitization degree and metal state. XPS was employed to determine atom state and element fraction. The electrochemical performance of the catalysts for ORR were evaluated in alkaline media at â0.8Â V to 0.2Â V. The Eonset and E1/2 with the values of â100Â mV and â170Â mV (vs Ag/AgCl) are achieved on Mn-N-C/CNT-800. The superior selectivity toward the 4eâ pathway are obtained on Mn-N-C/CNT-800 and Co-N-C/CNT-800 with the transferred electron numbers per O2 molecule of 4.12 and 3.94, respectively. Results show that the states of doped transition metal play a key role on determining ORR performance. The electron transfer number of Ni-N-C/CNT at â0.5Â V is increased from 3.22 (Ni-N-C/CNT-800) to 3.99 (Ni-N-C/CNT-600) when the metallic Ni has been eliminated at lower pyrolysis temperature.
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Physical Sciences and Engineering
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Authors
Yuying Gao, Li Wang, Guozhu Li, Zhourong Xiao, Qingfa Wang, Xiangwen Zhang,