Highly Efficient TiO2-X via Magnesiothermic Reduction for SunLight-Induced H2 Generation

Jong-Sung Yu

Abstract :

High efficiency with stable performance and utilization of visible light is a key challenge to sunlight-induced photochemical generation of H2, the cleanest energy carrier, using particulate photocatalyst system. Recently, black TiO2-x materials were achieved by creating oxygen vacancies and/or defects at the surface using different methods. Fascinatingly, they exhibited an extended absorption in VIS and IR instead of only UV light with a band gap decreases from 3.2 (anatase) to ~1 eV. However, despite the dramatic enhancement of optical absorption of black TiO2-x material, it fails to show expected visible light-assisted water splitting efficiency. Therefore, a black TiO2 material with optimized properties would be highly desired for visible light photocatalysis.

Herein, we report H-doped reduced reduced of TiO2-x nanoparticles prepared by a controlled reduction via the simultaneous presence of two active reducing species, [Mg] and [H] in confined microenvironment at TiO2 surface for excellent photocatalytic H2 production from methanol-water system. It exhibits outstanding activity (31.4 mmolg-1h-1) and excellent stability after Pt deposition for photochemical H2 generation from methanol-water in simulated sunlight. The excellent photoactivity of H:TiO2-x is attributed to the oxygen vacancies and H doping at TiO2 surface generated by [Mg] and [H]. The photocatalyst is working in the wavelength < 700 nm and exhibits reasonable visible-light activity with a quantum yield of 17.8, 7.62 and 3.72% at 400, 420 and 454 nm, respectively along with the exceptionally high turnover number (238680) with respect to Pt. This outstanding activity can be correlated with the extended absorption in visible light, perfect band position, presence of an appropriate amount of Ti3+ and oxygen vacancy, and slower charge recombination.



Feb. 1983,      Sogang University, Seoul, Korea, B.S. (honor) in Chemistry
April 1990,    University of Houston, Houston, TX, USA, Ph.D. in Chemistry


Professional Activities

1990-1991,            Research Fellow, Ohio State University
1998-1999             Research Fellow, Pennsylvaia State University
2004-2005,           Research Fellow, Northwestern University
2008-2015,           Professor, Dept. of Advanced Materials Chem., Korea University
2015-Present,       Professor, Dept. of Energy Systems Engineering, DGIST


Honors, Awards and Memberships

2013.12–Present,       Editorial board of frontiers in Fuel Cells
2012.03–2014.03,     Associate Editor of J. of Electrochemical Science and Technology
2012.05–2014.09,     2012, 2013 and 2014 Excellent Research Award in Korea Univ.
2011.05                       2011 International Conference on Clean Energy, Honor award, in Taiwan
2011.11                        Best Paper Award in International Conference on Advanced Electromaterials
2011.04                       Excellent Research Award in Inorganic Chemistry Division of Kor. Chem. Soc.
2005.05–Present,      Editorial board, J. of Experimental Nanoscience (Taylor and Francis)
2005.01–Present,      Editorial board, Carbon Letter (Korean Carbon Society)
2005.07                       Scientific Chair at 2005 Carbon International Conference
2004.07                       Excellent Research Award in Material Chemistry Division of Kor. Chem. Soc.
2004.06                       Grant for 2004 Korea Leading Scientists (2004.06 – 2007.05), KOSEF