ABSTRACT

In this study, detailed surface reaction mechanisms for CO/O₂ system on Pt/Al₂O₃ and Rh/Al₂O₃ have been developed based on the measurements of gaseous and surface species. The conventional conversion rate experiments for gaseous CO to CO₂ were conducted with the monolith honeycomb catalyst, and furthermore, the adsorbed surface species were identified with the powdered catalyst by in-situ FTIR under the same conditions as conversion rate experiment. As a result, it was found that only linear CO adsorption was detected for Pt, while twin CO adsorption was detected for Rh. Based on the results, detailed surface reaction mechanisms have been developed for Pt/Al₂O₃ and Rh/Al₂O₃. As a result of numerical simulation, it was confirmed that the variations of CO to CO₂ conversion rate with temperature were quantitatively reproduced for various O₂ concentration conditions. Furthermore, using those reaction mechanisms, CO conversion rate on bimetal, Pt/Rh Al₂O₃ catalysts were examined for several Pt/Rh ratios. Numerical simulation results for bimetal catalysts were also quantitatively agreed with experimental results for various Pt/Rh ratios as well as CO/O₂ ratios.

摘要

在这项研究中，基于对气体和表面物质的测量，已经开发了 CO/O ₂系统在 Pt/Al ₂ O ₃和 Rh/Al ₂ O ₃上的详细表面反应机制。气态CO到CO ₂的常规转化率实验是用整体蜂窝催化剂进行的，此外，在与转化率实验相同的条件下，通过原位FTIR对粉末状催化剂的吸附表面物种进行了鉴定。结果发现，Pt 仅检测到线性 CO 吸附，而 Rh 检测到双 CO 吸附。基于这些结果，已开发出 Pt/Al _{2 的}详细表面反应机制O ₃和Rh/Al ₂ O ₃。数值模拟的结果证实，对于各种O ₂浓度条件，CO 到CO ₂转化率随温度的变化被定量再现。此外，使用这些反应机制，针对几种 Pt/Rh 比率检查了双金属 Pt/Rh Al ₂ O ₃催化剂上的 CO 转化率。双金属催化剂的数值模拟结果也与各种 Pt/Rh 比率以及 CO/O ₂比率的实验结果在数量上一致。