NSF Young Investigator: Structural Tailoring of Nanoscale Materials for Catalysis and Ceramics

这是美国国家科学基金会颁发的青年研究员奖。这项研究致力于加工具有特殊表面反应性和物理性能的纳米材料，用于催化和陶瓷应用。一个目标是利用气体冷凝法制备的纳米颗粒的细小颗粒尺寸和增强的表面扩散，在相对较低的烧结温度下获得高密度材料。用X射线衍射、原子力显微镜和光声红外光谱观察了纳米结构材料的结构演变。还分析了这些材料在净成形和高温应用中的力学性能。纳米结构复合材料被合成为负载型金属催化剂；这些材料应该具有高的金属分散性和可能的增强的催化活性，并且可以被设计成具有高密度的均匀的纳米级孔。研究了纳米结构催化剂在化学制造过程中的热稳定性、选择性和反应活性，并与溶胶凝胶法和传统浸渍法制备的催化剂进行了比较。用小角X射线散射、穆斯堡尔谱、原子力显微镜、正电子湮没谱和量热法对催化剂进行了表征。用高温光声红外光谱跟踪了使用新型催化剂的反应动力学。

This is an NSF Young Investigator Award. The research addresses the processing of nanoscale materials with unusual surface reactivity and physical properties for catalysis and ceramic applications. One objective is to achieve highly dense materials at relatively low sintering temperatures by exploiting the small grain size and enhanced surface diffusion of nanometer-sized particles prepared by the gas condensation method. Structural evolution of the nanostructured materials is observed by X-ray diffraction, atomic force microscopy, and photoacoustic infrared spectroscopy. Mechanical properties of these materials are also analyzed for net-shape forming and high- temperature applications. Nanostructural composites are synthesized as supported metal catalysts; these materials should offer high metal dispersion and possibly enhanced catalytic activity, and can be engineered to have a high density of uniform nanoscale pores. The thermal stability, selectivity, and reactivity of nanostructure catalysts in chemical manufacturing processes are studied and compared to those of catalysts produced by sol-gel synthesis or traditional impregnation methods. Catalysts are characterized by small-angle X-ray scattering, Moessbauer spectroscopy, atomic force microscopy, positron annihilation spectroscopy, and calorimetry. Reaction kinetics of processes using the novel catalysts are followed with high-temperature photoacoustic infrared spectroscopy.