Modeling NOx Reduction on Catalytic Surfaces with Molecular Beam Techniques

这项建议是Francisco Zaera教授对燃烧废气在贵金属表面的催化反应研究的继续。Zaera教授的实验室专门使用分子束技术进行本征动力学测定，并使用表面红外振动光谱对化学吸附剂进行表征。根据先前的赠款，在高真空下观察到的动力学和机理与在催化反应条件下观察到的动力学和机理之间的关联方面取得了进展。在本方案中，将在高通量脉冲分子束条件下研究高温下Pd(和Rh)单晶上的NO和CO反应，以模拟真实的催化反应条件。此外，为了确定竞争吸附对吸附截面和反应动力学的影响，燃烧废气中的其他典型气体，如CO2、H2O、O2也将包括在分子束中。快速步进扫描红外反射吸收光谱仪将提供随时间变化的表面复盖率和成分信息。吸附机理将用蒙特卡罗方法模拟，反应参数将由暂态动力学研究得出。这项研究对开发新型的燃烧废气修复催化剂具有重要意义。它被认为是遵守现代全球气体排放标准的主要需要。

This proposal is a continuation of Prof. Francisco Zaera's investigation of the catalytic reaction of combustion exhaust gases on noble metal surfaces. Prof. Zaera's laboratory is specialized in the use of molecular beam techniques for intrinsic kinetics determination, and surface infrared vibrational spectroscopy for chemisorbate characterization. Under the previous grant, progress was made in correlating between kinetics and mechanisms observed under high-vacuum to those under catalytic reaction conditions. In the present proposal, NO and CO reactions on Pd (and Rh) single crystals at high temperature will be studied under high-flux pulsed molecular beam conditions, to resemble the real catalytic reaction conditions. In addition, other gases typical in combustion exhaust, e.g., CO2, H2O, O2, will be included in the molecular beam in order to determine the influence of competitive adsorption on the adsorption cross-section and the reaction kinetics. A rapid step-scanning infrared reflection-absorption spectroscope will provide the time-dependent surface coverage and composition information. The mechanism of adsorption will be modeled with Monte-Carlo techniques and the reaction parameters will be derived from the transient kinetics study. This research has significant implications in the development of novel catalysts for the remediation of combustion exhaust gases. It is recognized as a primary need in complying with modern global standards of gas emission.