Effect of composition and partical size in oxidation catalysis by metal oxide solid solution nanoparticles

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In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Marjorie Langell of the University of Nebraska at Lincoln is investigating methods of tailoring nanometer-sized, heterogeneous catalysts by their chemical composition and crystallite size. The project targets the improvement of catalytic efficiency and selectivity, which would be important for the chemical manufacturing sector and sustainable growth. The catalysts are suitable for use in the energy sector in natural gas power generators, solid-state fuel cells, and petrochemical cracking. There are also applications in pollution abatement and in photochemical (solar) chemistry. For broader impacts on human capital, the project trains graduate and undergraduate students, and includes national laboratory experience for these researchers. The project also involves outreach to encourage high school students to pursue undergraduate chemistry degrees and to increase understanding of catalysis and nanoscience by demonstrations and activities readily available to the general public.The bimetallic oxide catalysts are being synthesized in nanoscale form by combinatorial hydrothermal-solvothermal methods and characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), and x-ray absorption fine structure (XAFS). The materials are being evaluated for reactivity in the water gas shift reaction, carbon monoxide (CO) oxidation, and the oxidative dehydrogenation of methanol. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) measure possible surface segregation and identify adsorbate species, and temperature programmed desorption (TPD) determines the activation energies and helps in identifying reaction mechanisms. Atmospheric pressure studies, performed in a catalyst characterization system, follow the catalytic reactions with products detected by gas chromatography-mass spectrometry (GC-MS).