Oxygen Electrocatalysis by Transition Metal Spinel Oxides
Zhichuan is an associate professor in the School of Materials Science and Engineering, Nanyang Technological University. He received his PhD degree in Electroanalytical Chemistry at 2008 and B.S. degree in Chemistry at 2002 from Lanzhou University, China. His PhD training was received in Lanzhou University (2002-2004), Institute of Physics, CAS (2004-2005), and Brown University (2005-2007). Since 2007, he worked in State University of New York at Binghamton as a Research Associate and from 2009 he worked in Massachusetts Institute of Technology as a Postdoctoral Researcher. He was shortlisted as the finalist of 2012 NRF Fellowship. He is top 10% highly cited authors in RSC chemistry journals in 2014. Dr. Xu has received several awards such as Chun-Tsung Endowment Outstanding Contribution Award - Excellent Scholar at 2018 and the Zhaowu Tian Prize for Energy Electrochemistry by International Society of Electrochemistry (ISE) at 2019. Dr. Xu is a member of the International Society of Electrochemistry (ISE), The Electrochemistry Society (ECS), and the American Association for the Advancement of Science (AAAS). He was awarded Fellow of Royal Society of Chemistry (FRSC) on Nov. 2017. He served as guest editors for Electrochimica Acta and Chemistry -- A European Journal, and an associate editor for Nano-Micro Letters. He is also the development editor for Current Opinion in Electrochemistry and the president of ECS Singapore Section. Dr. Xu is a Highly Cited Researcher by Clarivate Analytics, Web of Science (2018 and 2019).
Exploring efficient and low cost oxygen electrocatalysts for ORR and OER is critical for developing renewable energy technologies like fuel cells, metal-air batteries, and water electrolyzers. This presentation will presents a systematic study on oxygen electrocatalysis (ORR and OER) of transition metal spinel oxides. Starting with a model system of Mn-Co spinel, the presentation will introduce the correlation of oxygen catalytic activities of these oxides and their intrinsic chemical properties. The catalytic activity was measured by rotating disk technique and the intrinsic chemical properties were probed by synchrotron X-ray absorption techniques. It was found that molecular orbital theory is able to well-explain their activities. The attention was further extended from cubic Mn-Co spinels to tetragonal Mn-Co spinels and it was found that the molecular theory is again dominant in determining the catalytic activies. This mechanistic principle is further applied to explain the ORR/OER activities of other spinels containing other transition metals (Fe, Ni, Zn, Li, and etc.). The talk further gives insight on surface reconstruction on spinel oxides and how the bulk properties affect such reconstruction during OER.
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 Zhou, Y.; Sun, S.; Wei, C.; Sun, Y.; Xi, P.; Feng, Z.; Xu, Z. Adv. Mater. DOI: 10.1002/adma.201902509 (2019)
 Wu, T.; Sun, S.; Song, J.; Xi, S.; Du, Y.; Chen, B.; Sasangka, W. A.; Liao, H.; Gan, C. L.; Scherer, G.; Zeng, L.; Wang, H.; Li, H.; Grimaud, A.; Xu, Z. Nat. Catal., DOI: 10.1038/s41929-019-0325-4 (2019)