Research Interests and Projects
Understanding complex systems at the molecular level is important but difficult using experiments alone. Computer simulations based on fundamental physical and chemical principles can complement experiments and provide new insights into the behavior of these systems. My research program is centered on the investigation of the molecular processes that govern materials processing and catalytic properties. State-of-the-art theoretical methods combined with molecular simulations are employed in our research. Particularly, we are interested in the following projects
I. Activation and Conversion of CO2 and CH4.
Climate change resulting from anthropogenic green house gases, mainly carbon dioxide, is widely considered as a major threat faced by mankind. Recycling carbon dioxide in the production of useful chemicals or liquid fuel will complement carbon capture and sequestration and have a positive impact on global carbon dioxide levels, but such a process requires energy or hydrogen sources. In this project, we exploit methane as both hydrogen and energy source in a combined catalytic conversion process.
Recent publications: J. Catal. 317, 44(2014); 272, 227(2010); ACS Catal. 3, 1296(2013); Langmuir, 26, 5551 (2010); 24, 12410 (2008); JPCC 116, 7817 (2012); Catal. Today 147, 68 (2009); 194, 30(2012).
II. Hydrogen storage in metal complex hydride and other novel materials
For on-board vehicle applications, hydrogen storage systems are required to provide the needed quantity of hydrogen with acceptable volume, weight, cost, and safety risk as compared with the current gasoline-driven combustion engine. Light-metal complex hydrides hold great promise as potential hydrogen storage media due to their intrinsic high hydrogen content and recently demonstrated reversibility for hydrogen release and uptake. Our overall goal is to develop a multiscale approach to model desorption and adsorption of hydrogen in complex metal hydrides. We predicted the TiAl3Hx complex as the precursor for forming TiAl3 alloy observed in Ti-doped NaAlH4. The predicted TiAl3H12 structure was confirmed by an experimental study. We then showed that doped 3d transition metals form similar interstitial structures, and examined the effect of doped transition metals on reversible hydrogen release/uptake from NaAlH4.
Recent publications: IJHE, 38, 3670(2013); JPCC 113, 8513 (2009); 115, 2522(2011); JPCA 114, 12318 (2010); 117, 8099(2013); JCTC 5, 2079 (2009); Chem. Eur. J. 15. 1685(2009).
III. Support effect for metal oxide catalysts
Current commercial heterogeneous catalysts with metal oxides as active species are difficult to study experimentally due to their structural and chemical complexity. Our research in this broad area aims at providing atomic level understanding of some technologically, economically and environmentally important processes, such as NOx storage and reduction. The projects in this area involve collaborations with the computational and experimental groups (Drs. Donghai Mei, Chuck Peden, Zdenek Dohlnek, and Bruce Kay) of the Institute of Interfacial Catalysis at PNNL.
Recent publications: Catal. Today 151, 304(2010); JPCC 113, 18296 (2009); 113, 7779 (2009); 112, 18050 (2008); 112, 16924; PCCP 11, 3380(2009); PRL 101, 156103 (2008).