Prof. Jeffery's Talk

Jan 16, 2017 - 17:00

Jan 16, 2017 - 18:00

Rm. No. 118 Ground floor Chemical Engg. Dept.

Seminars

Prof. Jeffery C.S. Wu National Taiwan University

Abstract: Global warming and energy shortage raise the concern about greenhouse gases and renewable energy. One of the best routes to covert CO2 into renewable energy and simultaneously reduce the concentration of CO2 in atmosphere is photosynthesis[1]. This study explored the photocatalytic hydrogenation of CO2 by a novel twin reactor to mimic photosynthesis process under light irradiation. The Z-scheme of water splitting is comprised of H2-photocatalyst and O2-photocatalyst with aid of electron transfer mediator to produce hydrogen and oxygen respectively [2]. A novel twin reactor which divided H2-photocatalyst and O2-photocatalyst in two compartments using a membrane can separate H2 and O2 thus preventing backward reaction. Pt/SrTiO3:Rh and BiVO4 were used as the H2-photocatalyst and the O2-photocatalyst respectively. The diffusion of electron mediator Fe2+/Fe3+ through Nafion membrane was investigated. The transfer rate of mediator ions was remarkably higher than the photoreaction rate indicating that membrane did not delay the water-splitting reaction in the twin reactor[3]. The CO2 hydrogenation was carried out in the H2 side of the twin reactor. Photocatalytic reaction was performed under AM 1.5G sunlight. Oxygen can be released from the O2 side of the twin reactor. Simultaneously H+ was diffused through the membrane to the H2 side. CO2 was purged in the H2 side then reduced to hydrocarbons by photocatalyst [4]. A series of sol-gel prepared InTaO4 were loaded with different metal oxide such as NiO RuO2 Cu(OH)2 and Pt were as co-catalysts. The UV-VIS spectra of this series catalysts indicated that the photocatalysts could absorb visible light. These CO2 hydrogenation catalysts were applied into the twin photoreactor. In aqueous system which catalyst was dispersed in the solution the maximum yields of methanol and acetaldehyde were 9.27 μmole/g•hr and 11.30 μmole/g•hr at 25oC. The twin photoreactor gave higher yields of CO2 than those in the single reactor because the backward (oxidation) reaction was inhibited by separating O2 in the other side [5]. References: [1] N. A. Campbell J. B. Reece E. J. Simon Essential biology Chapter 7 p. 105 Pearson/Benjamin Cummings San Francisco 2004 [2] R. Abe K. Sayama K. Domen H. Arakawa Chem. Phys. Lett. 344 (2001) pp. 339-344 [3] C.-C. Lo C.-W. Huang C.-H. Liao J. C. S. Wu Int. J. Hydrogen Energy 35(4) 1523-1529 (2010) [4] S.-C. Yu C.-W. Huang C.-H. Liao J. C. S. Wu S.-T. Chang K.-H. Chen J. Membr. Sci. 382(1-2) 291-299 (2011) [5] W.-H. Lee C.-H. Liao M.-F. Tsai C.-W. Huang J. C. S. Wu Appl. Catal. B: Environ. 132-133 445-451(2013) Bio: Jeffrey C. S. Wu is professor and chair of the Chemical Engineering Department National Taiwan University. He received his PhD D degree in Chemical Engineering from University of Pittsburgh USA in 1988. From 1989 to 1994 he was a Senior Research Engineer at Alumina Company of America (Alcoa) Pittsburgh Pennsylvania USA. Professor Wu is a member of the Taiwan Institute of Chemical Engineers and Taiwan Institute of Engineers. He is author and coauthor of over 100 SCI journal papers one book chapter and two textbooks of Chemical Industry and Catalysis. His research interest is photocatalysis include (a) photoreduction of CO2 to fuel (b) photocatalytic water splitting for H2 and (c) photocatalytic oxidation of air pollutants. He has received a number of awards including (1) Outstanding Engineering Professors Award Chinese Institute of Engineers Taiwan in 2016; (2) Outstanding Cross-Sector Collaboration Award 2nd National Industrial Innovation in 2012; (3) Lai Tzai-Der award of Taiwan Institute of Chemical Engineers in 2009; (4) Chemical Technology Award of Taiwan Institute of Chemical Engineers in 2006 and (5) Silver medal of National Invention Taiwan in 2004. Currently He is the editor of Catalysis Communications. He also serves as a member of editorial boards of Applied Catalysis A: General Chemical Engineering Journal Journal of CO2 Utilization and Journal of Photocatalysis Science.