Nano-structured noble metals and noble metal oxides are used in proton exchange membrane (PEM) fuel cells and water electrolyzers for their electro-catalytic activity. The combined generation of acidic protons and the high electrochemical potentials require that the catalysts remain stable under these extremely corrosive environments. The cost of noble metals thus provides the impetus to search for stable catalyst supports to minimize the loading while also enhancing the electrocatalytic activity. Very few materials are known to exhibit the desired electrical conductivity and electrochemical stability at 1.8-2.0V. Group IV oxide particularly, SnO2 is known to exhibit the desired electrochemical stability as well as moderate electronic conductivity. There is a need to further improve its electronic conductivity to enhance the efficiency of the electro-catalytic activity and minimize the catalyst loading. This project will conduct a fundamental experimental and theoretical study to identify a new class of different SnO2 based materials that likely exhibit improved electrochemical and electronic properties for electrolysis of water. The approach will be to use first principles ab initio techniques to determine thermodynamically stable mixed metal oxides while also using the Gaussian methodology to identify the electrochemical stability of the parent and doped tin oxide at the desired electrochemical potentials. Novel chemical approaches will be used to generate high surface area Ir1-xRuxO2 catalyst structures on these stable catalyst supports. The role of bulk and surface microstructure and composition on the electrochemical stability and the electrocatalytic response will be studied by correlating high resolution microscopy results with logical electrochemical potentiometric, and electronic conductivity tests.
Intellectual merits: A new class of nano-crystalline mixed metal oxide catalyst supports exhibiting desirable electronic conductivity and electrochemical properties will be developed, and a better understanding of the underlying electrochemical processes and the influence of nano-scale materials structure and microstructure on the electrochemical stability and activity will be generated; 3) The combination of theory and experiments will lay the foundation for the design and development of novel catalyst supports for the generation of carbon free hydrogen using electrolysis of water. Broader impacts: The proposed research will advance the science and technology of mixed metal oxides for electrocatalysis for use in PEM fuel cells and water electrolysis. The proposed studies will offer an excellent opportunity for minority women and individuals from underrepresented groups to participate in the research activity. The on-going existing collaboration with North Carolina Agriculture and Technical University (NCAT) through the recently funded NSF-Engineering Research Center (ERC) will further help to recruit minority individuals into the graduate program. Moreover, web-based audio-visual electrochemistry tools will be developed for local high school students who will be allowed to participate in projects in the PI's laboratory and present their work in a competitive workshop.
