Presenter：Bin Liu, Schoolof Chemical and Biomedical Engineering, Nanyang Technological University
Topic：Identificationof Co2+ in Spinel Co3O4 as Active Sites forWater Oxidation
Time： 09：30AM,July 21st
Location：909-B
Abstract
Spinel cobalt oxide (Co3O4)has been extensively studied as promising electrocatalyst for water oxidation.It is believed that the cobalt ions in spinel Co3O4 should be oxidized during the oxygen evolution reaction (OER). Therefore, theobserved evident anodic peak prior to the rise of the OER current in the linearsweep voltammetry (LSV) scan in spinel Co3O4 was ascribedto the oxidation of cobalt ions accompanying with a phase transformation. Here,through a combination of independent in-situ measurements including X-ray absorption and grazing-angle X-ray diffractionunder operando conditions, we found that both the spinel structure and cobaltvalence states in Co3O4 remained unchanged duringelectrochemical water oxidation. Following a potential-resolved in-situ Raman analysis, it was revealedthat the anodic peak current could be mainly contributed from the formation ofperoxide moieties (e.g., Co-OO-Co or Co-OOH) on the surface of Co3O4,and more importantly, the tetrahedral Co2+ ions in Co3O4 should be the crucial sites to bridge the μ-OO bond.
Biography
Bin Liu received hisB.Eng. (1st Class Honors) and M.Eng. degrees in Chemical Engineering from theNational University of Singapore, and obtained his Ph.D. degree in ChemicalEngineering fromUniversityofMinnesotain 2011.Thereafter, he moved toUniversityofCalifornia,Berkeleyand worked as a postdoctoral researcher in Department of Chemistry during 2011� 2012 before joiningSchoolofChemicaland Biomedical Engineering atNanyangTechnologicalUniversityas an Assistant Professor in 2012. His main research interests areelectrocatalysis, photovoltaics and photoelectrochemistry. More information canbe found at http://www.ntu.edu.sg/home/liubin/home.html.
Contact: Yanguang Li
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