【Topic】：Mechanistic Understanding of Electrochemical C=O Reduction Enables Selective Production of Biorenewable Chemicals
【Time】：14:00-15:30 on May 25, 2017
【Speaker】：Dr. Wenzhen Li
Richard Seagrave Associate Professor in the Department of Chemical and Biological Engineering Department Iowa State University
Electrochemical reduction of biorenewable platform chemicals is an emerging route for sustainable biofuel and chemicals production. However understanding gaps between reaction conditions, underlying mechanisms, and observed product selectivity have limited the rational design of effective, active, and stable electrochemical systems. Herein, we investigate the mechanisms and tunability of electrochemical reduction of C=O, using furfural (C5H4O2) as a model biomass-derived furanic compound. We demonstrate that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (1) electrocatalytic hydrogenation/hydrogenolysis (ECH) and (2) direct electrochemical reduction. Through novel electrochemical techniques we clarified the nature of heterogeneous electron transfers (ET) occurring for formation of furfuryl alcohol, 2-methylfuran (outer sphere ET), and hydrodimerization (inner sphere ET) products. Electrochemical H/D isotope studies revealed that formation of key products require electrochemically adsorbed hydrogen, namely by the ECH mechanism. Cyclic voltammetry and bulk electrolysis results clarify the reaction pathways of 2-methylfuran and furfuryl alcohol formation under these conditions, and furfural alcohol is not a reaction intermediate to methylfuran product. Finally, understanding of the underlying mechanisms enabled us to manipulate the electrochemical reduction of furfural by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important bio-based polymer precursors and fuels. Our recent research in electrochemical reduction of furfural on Pb electrode and a paired electrolyzer for integration of HMF oxidation and reduction for valuable chemical production will be briefly introduced.
Dr. Wenzhen Li is a Richard Seagrave Associate Professor in the Department of Chemical and Biological Engineering Department at Iowa State University and an Associate Scientist at US DOE Ames Lab. His research interests are in the areas of catalysis, electrochemical energy, biorenewables and advanced materials. Dr. Li has 87 peer-reviewed journal articles with 9200+ citations, 6 issued patents, and his h-index is 42. He is one of the pioneer researchers who discovered that carbon nanotubes can serve as a better fuel cell catalyst support than conventional carbon black, and explored integration of renewable electricity and renewable carbon for chemicals and fuels production. His current research activities include developing advanced electrocatalysts and electrochemical reactors for flexible, decentralized and modular chemicals manufacturing from biorenewables, CO2 and N2 feedstock, and novel efficient redox flow batteries and electrolyzers for energy storage. Dr. Li received his Ph.D. with honors from Dalian Institute of Chemical Physics of Chinese Academy of Sciences under guidance of Profs. Qin Xin and Gongqun Sun; and had worked as postdoctoral researcher with Prof. Masahiro Watanabe at University of Yamanashi, and with Prof. Yushan Yan at University of California Riverside; as research scientist at SUNY Albany College of Nanoscale Science and Engineering, and as assistant to associate professor at Michigan Technological University. His research projects are funded by US-Nation Science Foundation (NSF), US-DOE-Advanced Research Projects Agency-Energy (ARPA-E) and Iowa Energy Center (IEC).