报告题目：Investigation of heterogeneous molecular structure for electrocatalysis applications

报告人：WANG Xin（Nanyang Technological University）

报告时间：2019年12月7日 10：00-11：00

报告地点：华南理工大学环境与能源学院B4-308

报告人简介：Prof. Xin Wang received his Bachelor (1994) and Master (1997) degrees in Chemical Engineering from Zhejiang University, and Ph. D (2002) in Chemical Engineering from Hong Kong University of Science and Technology. From 2003 to 2005, he worked as a research fellow at University of California, Riverside, and concurrently, as R&D director for a startup fuel cell company. He joined Nanyang Technological University as assistant professor in 2005 and was promoted to associate professor with tenure in 2010 and full professor in 2016. He is currently the Chair of School of Chemical and Biomedical Engineering. He has been working on electrocatalysis and electrochemical technology for energy harvesting. His recent research focus includes 1) rational design of functional nanomaterials for electrocatalysis in energy and environmental applications such as fuel cells, CO₂ electro-reduction and water splitting, and 2) electrochemical reactor with co-generation of electricity and valuable chemicals. He has published ~200 SCI papers with citations over 19500 (Web of Science) and H index of 73. He is a Fellow of Royal Society of Chemistry (FRSC) and Clarivate Analytics Highly Cited Researcher 2018 and 2019.

报告内容：Molecular Co²⁺ ions were grafted onto doped graphene in a coordination environment, resulting in the formation of molecularly well-defined, highly active electrocatalytic sites at a heterogeneous interface for the oxygen evolution reaction (OER). The S dopants of graphene are suggested to be one of the binding sites and to be responsible for improving the intrinsic activity of the Co sites. The turnover frequency of such Co sites is greater than that of many Co-based nanostructures and IrO₂ catalysts. Through a series of carefully designed experiments, the pathway for the evolution of the Co cation-based molecular catalyst for the OER was further demonstrated on such a single Co-ion site for the first time. In another demonstration of molecular Ni²⁺ based system, we found for the first time that the presence of Fe³⁺ ions in the solution could bond at the vicinity of the Ni sites with a distance of 2.7 Å, generating molecularly sized and heterogeneous Ni-Fe sites anchored on doped graphene. These Ni-Fe sites exhibited drastically improved OER activity. It is revealed that the Ni-Fe sites adsorbed HO‾ ions with a bridge geometry, which facilitated the OER electrocatalysis.