Affiliation: | 1. Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260 USA These authors contributed equally to this work.;2. School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR, 97331 USA These authors contributed equally to this work.;3. Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260 USA;4. School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR, 97331 USA;5. DND-CAT, Synchrotron Research Center, Northwestern University, Evanston, IL, 60208 USA;6. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831 USA |
Abstract: | Atomically dispersed and nitrogen coordinated single metal sites (M-N-C, M=Fe, Co, Ni, Mn) are the popular platinum group-metal (PGM)-free catalysts for many electrochemical reactions. Traditional wet-chemistry catalyst synthesis often requires complex procedures with unsatisfied reproducibility and scalability. Here, we report a facile chemical vapor deposition (CVD) strategy to synthesize the promising M-N-C catalysts. The deposition of gaseous 2-methylimidazole onto M-doped ZnO substrates, followed by an in situ thermal activation, effectively generated single metal sites well dispersed into porous carbon. In particular, an optimal CVD-derived Fe-N-C catalyst exclusively contains atomically dispersed FeN4 sites with increased Fe loading relative to other catalysts from wet-chemistry synthesis. The catalyst exhibited outstanding oxygen-reduction activity in acidic electrolytes, which was further studied in proton-exchange membrane fuel cells with encouraging performance. |