Mixed-Conductor Enhanced Redox Materials

Mixed-Conductor Enhanced Redox Materials and Their Applications in Clean Energy Conversions
Fanxing Li
Assistant Professor
Chemical and Biomolecular Engineering Department, 
North Carolina State University, U.S.A
2013-06-26 10:00
Conversion of methane into syngas, a gaseous mixture composed primarily of carbon monoxide and hydrogen, is a topic of practical relevance for many synthetic fuel and chemical production processes. At present, most methane-derived syngas is produced through reforming in the presence of gaseous oxidants such as steam, oxygen, and/or carbon dioxide. Although the reforming based approaches have been successfully utilized at a commercial scale, the efficiencies of the state-of-the-art reforming processes are limited due to the high steam to methane ratio required by the reforming catalysts and/or the needs for energy intensive air separation operations. The current study investigates the feasibility of converting methane into syngas using a solid, oxygen-carrying material. In a so-called “redox reforming scheme”, lattice oxygen contained in a redox catalyst is used to partially oxidize methane into syngas. In a subsequent regeneration step, the lattice oxygen consumed during the methane oxidation step is replenished with air.  A number of surface-modified redox catalysts composed of a primary metal oxide, mixed ionic-electronic conductor (MIEC), and/or catalytically active transition metals are synthesized and characterized. Preliminary results indicate that the newly developed redox catalyst are significantly more reactive than conventional, TiO2 supported oxygen carriers used in the so-called chemical looping processes. They are also found to possess excellent stability through multiple redox cycles. These redox catalysts also exhibit good potential in terms of resistance towards carbon formation and selectivity towards syngas products.
Besides methane partial oxidation, a number of other applications of redox materials including chemical looping combustion and oxidative methane coupling are also discussed. Other research topics being explored at the presenter’s research group will also be briefly covered.
Dr. Fanxing Li is an Assistant Professor in the Chemical and Biomolecular Engineering Department at the North Carolina State University. Dr. Li received his BS and MS degrees in chemical engineering from Tsinghua University in 2001 and 2004, respectively. He received his PhD at the Ohio State University in 2009. Dr. Li has published 25 journal articles and book chapters and invented/co-invented 7 patents. He has won numerous international awards, including the prestigious Best PhD in Particle Technology Award and the U.S. National Science Foundation CAREER Award.