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

在这个由化学学部化学催化项目资助的项目中，内布拉斯加州大学林肯分校的Marjorie Langell教授正在研究根据化学成分和晶体尺寸定制纳米尺寸的非均相催化剂的方法。该项目的目标是提高催化效率和选择性，这对化学制造部门和可持续增长非常重要。该催化剂适用于天然气发电机、固态燃料电池和石化裂解等能源领域。在污染治理和光化学（太阳能）化学方面也有应用。为了对人力资本产生更广泛的影响，该项目培训研究生和本科生，并为这些研究人员提供国家实验室经验。该项目还包括鼓励高中生攻读本科化学学位，并通过向公众提供的示范和活动来增加对催化和纳米科学的理解。采用水热-溶剂热相结合的方法合成了纳米形式的双金属氧化物催化剂，并用x射线衍射（XRD）、透射电子显微镜（TEM）和x射线吸收精细结构（XAFS）对催化剂进行了表征。这些材料在水煤气变换反应、一氧化碳氧化和甲醇氧化脱氢中的反应活性正在被评估。x射线光电子能谱（XPS）和次级离子质谱（SIMS）测量可能的表面偏析并鉴定吸附质种类，程序升温解吸（TPD）确定活化能并有助于鉴定反应机理。在催化剂表征系统中进行的大气压研究，通过气相色谱-质谱（GC-MS）检测催化反应的产物。

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).