RUI: CAS: Mapping Catalytic Sites on Alkali Promoted Anatase Titanium Dioxide (TiO2)

St. John Fisher College

Investigators

Abstract

Lowering the cost of renewable fuel production is a key goal for a society moving toward a sustainable economy. Substances that accelerate chemical reactions without themselves being consumed, commonly referred to as catalysts, will continue to be the key element towards achieving this goal. Recent advances suggest new ways of improving catalysts by modifying the shape of the catalyst particles. The proper shape exposes the catalyst’s most useful reactive sites while minimizing other sites that are either unreactive or that lead to undesirable side reactions and waste. With funds from the Chemical Catalysis Program in the Division of Chemistry, Dr. Alexey Ignatchenko of St. John Fisher College is fine-tuning catalyst shapes to maximize catalyst effectiveness for the preparation of industrial chemicals and biofuels. Cost savings in catalytic biofuel processing brings a clear economic benefit to society. The study provides enriching research experiences for undergraduate students from a predominantly undergraduate institution. The students interact with scientists at the Oak Ridge National Laboratory and use the specialized instruments housed at the Center for Nano Materials. The project prepares students to be the next generation of scientists engaged in renewable energy research that will ensure our country’s energy independence. The success of many renewable energy technologies depends on detailed knowledge about the structure of reactive catalytic centers and the mechanism of their action on the atomic scale. With funding from the Chemical Catalysis Program, Dr. Alexey Ignatchenko of St. John Fisher College is strategically selecting the best available surface of anatase TiO2 crystals and further fine-tuning its catalytic activity by alkali doping. His research group studies catalytic centers created by adding potassium and cesium separately to (001) or (101) surfaces of anatase TiO2 single crystals as well as on nano shaped particles enriched by one of the surfaces. A combination of theoretical and experimental methods, such as Density Functional Theory (DFT) computations, Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTS), X-Ray Photoelectron Spectroscopy (XPS), electron microscopy analysis, and catalytic activity testing of individual surfaces is applied to understand the role of acidic and basic catalytic centers in the reaction mechanism of the decarboxylative ketonization reaction, which is important for upgrading biofuels. This study is guiding research and development in rational modification of the type, amount, or location of the alkali promoters and the satellite basic centers made of oxygen, –OH, and –O– for many other catalytic reactions. The students involved in the project learn how to control the activity and selectivity of a catalytic process by manipulating catalyst structures at the molecular level and by refining critical steps of the reaction mechanism. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.