Affiliation: | 1. Centre for Integrated Nanostructure Physics (CINAP), Institute of Basic Science (IBS), 2066 Seoburo, Jangan-Gu, Suwon, 16419 Republic of Korea Department of Chemistry, Sungkyunkwan University (SKKU), 2066 Seoburo, Jangan-Gu, Suwon, 16419 Republic of Korea;2. Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049 China;3. State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049 China;4. Department of Computer Science and Engineering, Sungkyunkwan University (SKKU), 2066 Seoburo, Jangan-Gu, Suwon, 16419 Republic of Korea;5. Department of Chemistry, University of Puerto Rico, San Juan, PR, 00931 USA;6. Centre for Integrated Nanostructure Physics (CINAP), Institute of Basic Science (IBS), 2066 Seoburo, Jangan-Gu, Suwon, 16419 Republic of Korea;7. Department of Physics and Astronomy, Mississippi State University, Mississippi State, MS, 39762 USA |
Abstract: | Single-atom catalysts (SACs) have become the forefront of energy conversion studies, but unfortunately, the origin of their activity and the interpretation of the synchrotron spectrograms of these materials remain ambiguous. Here, systematic density functional theory computations reveal that the edge sites—zigzag and armchair—are responsible for the activity of the graphene-based Co (cobalt) SACs toward hydrogen evolution reaction (HER). Then, edge-rich (E)-Co single atoms (SAs) were rationally synthesized guided by theoretical results. Supervised learning techniques are applied to interpret the measured synchrotron spectrum of E-Co SAs. The obtained local environments of Co SAs, 65.49% of Co-4N-plane, 13.64% in Co-2N-armchair, and 20.86% in Co-2N-zigzag, are consistent with Athena fitting. Remarkably, E-Co SAs show even better HER electrocatalytic performance than commercial Pt/C at high current density. Using the joint effort of theoretical modeling, thorough characterization of the catalysts aided by supervised learning, and catalytic performance evaluations, this study not only uncovers the activity origin of Co SACs for HER but also lays the cornerstone for the rational design and structural analysis of nanocatalysts. |