The proposal seeks to understand and re-design high-temperature water-gas shift (WGS) catalysts so as to avoid the use of chromium (an element with potential environmental and health risks). Currently, chromium-containing catalysts are used almost exclusively for this important reaction that generates hydrogen from carbon monoxide and water, thereby contributing to a sustainable hydrogen-based energy economy. The project will utilize state-of-the art catalyst characterization and mechanistic tools to understand the detailed surface reactions that occur under high-temperature water-gas shift reaction conditions, and then propose new formulations based on known properties of potential low-cost substitute materials.
The study will examine both conventional and model HT-WGS catalysts for both their bulk and surface chemical and physical states under reaction conditions. The PI has many state-of-the-art characterization tools at his disposal that should allow unprecedented insight into the mechanism by which the current chromium-based catalyst functions. He will then attempt to emulate the properties of chromium by using a novel "controlled synthesis" method that will be employed with various earth-abundant candidate catalyst materials. The fundamental understanding obtained on the commercial chromium-containing catalyst should provide guidance on the structure, composition and redox properties needed to match the chromium-containing catalyst. In additional to a suite of spectroscopic tools, the PI will employ standard reactivity testing methods and studies with isotopically labeled species to gain detailed understanding of both the working catalyst composition and the WGS reaction mechanism.
The proposed research, if successful in all aspects, could transform the industrial process for HT-WGS while avoiding environmental and health issues associated with the current use of chromium. The project would also contribute to the realization of a sustainable hydrogen economy, which would improve U.S. energy security and help ensure competitiveness of the U.S. chemical industry. From an educational standpoint, the project will train one graduate student and 4-6 undergraduate students. In addition the PI will continue his longstanding involvement in a number of educational outreach programs in the Lehigh Valley area, including the Lehigh University CHOICES program that annually brings middle-school female students to the campus for a day to interact with faculty and students engaged in STEM activities.
