Due to recent advances in shale gas production, increased natural gas recovery, and reduced natural gas prices, the United States has an abundance of cheap natural gas. Methane, the primary component of natural gas, has found widespread use as a fuel for electricity generation; however it is not a good feedstock for the production of chemicals or transportation fuels such as gasoline or diesel. This stems from the difficulty in selectively oxidizing methane by insertion of an oxygen atom into a strong carbon-hydrogen bond while preventing the complete combustion to carbon dioxide and water. Gold is known to be inert when exposed to oxygen or air, but when it divided into small nanoparticles, it starts to catalyze the oxidation of carbon monoxide. Dr. Grabow of the University of Houston and Dr. Chandler of Trinity University have recently discovered a mechanism whereby water acts as a co-catalyst during CO oxidation over gold nanoparticles supported on titanium-oxide. They are now translating this knowledge to enable the partial oxidation of methane and other alkanes to form the corresponding alcohol. The team follows a collaborative and tightly coupled approach using computational and experimental studies to quantify the promotional effect of water on selective oxidation and to investigate the dominant reaction mechanism for oxygen insertion into carbon-hydrogen bonds. With over 7.72 trillion m3 of confirmed natural gas reserves, there is a huge incentive to develop commercially-viable methane conversion processes to benefit the U.S. economy and achieve national energy independence. The research activities are integrated with broad-reaching educational efforts at the K-12, undergraduate, graduate and professional level to broaden the participation of minority students and increase the retention of at-risk students at both participating universities. The University of Houston is a designated Hispanic-Serving Institution and has the most ethnically balanced student body of all major research institutions in the U.S. Trinity University provides research active undergraduate education to San Antonio and the South Texas region, which are largely populated by a traditionally underrepresented group in the STEM disciplines. Together, the principal investigators have a strong record for mentoring research projects for undergraduate, minority and female students.
Dr. Lars Grabow of the University of Houston and Dr. Bert Chandler of Trinity University are funded by the Chemical Catalysis Program at NSF to study oxygen insertion reactions into carbon-hydrogen (C-H) bonds over supported gold catalysts. The ultimate goal is to convert methane to methanol selectively, and a rational approach to the problem requires the close integration of theoretical (Grabow) and experimental (Chandler) techniques. The prevailing challenge in all processes using methane as a feedstock is activating the strong C-H bond; hence, the initial focus is on higher alkanes with weaker C-H bonds to acquire pertinent knowledge about the oxygen (O) insertion mechanism. To realize the possibility of using small amounts of water to improve the activity and selectivity of oxidation reactions over supported gold (Au) catalysts, the team quantifies the amount of surface water on different supports, investigates the dominant reaction mechanism for oxygen insertion into C-H bonds, and improves the product yield as guided by computational predictions. The selected application, O insertion into C-H bonds of alkanes, is a challenging fundamental problem in chemistry with far reaching technological impact for upgrading of natural gas to benefit the U.S. economy and achieve national energy independence. This concept can also be extended to other difficult selective oxidation reactions, e.g. ethylene epoxidation. Research activities are integrated with broad-reaching educational efforts at the K-12, undergraduate, graduate and professional level to broaden the participation of minority students and increase the retention of at-risk students at both participating universities. Together, the principal investigators have a strong record for mentoring research projects for undergraduate, minority and female students.
