Pd-Rh/TiO2光催化CO2氧化乙烷脱氢研究

采用浸渍还原方法制备Pd-Rh/TiO₂催化剂用于常温光催化CO₂氧化乙烷脱氢制C₂H₄。研究不同Pd/Rh比催化剂的光反应性能，利用XRD、EDX-mapping、TEM、HRTEM、XPS技术表征催化剂表面和电子特性，通过UV-Vis、PL技术考察催化剂光响应性能，采用原位红外光谱技术分析Pd-Rh/TiO₂光催化CO₂氧化乙烷脱氢反应机理。研究表明，Pd-Rh双金属体系可有效提高光反应活性，光照下Pd和Rh金属之间存在内部电子转移的作用，降低了Pd表面的电子云密度，促进光生电子和空穴的分离，同时促进了C₂H₆和CO₂在材料表面的吸附。Ar替换CO₂的对比实验证明，反应中的CO₂消耗H₂，可消除催化剂表面积碳，促进C₂H₄生成。

Study on the photocatalytic oxidative dehydrogenation of ethane with CO2 over Pd-Rh /TiO2 catalyst

Pd-Rh/ TiO₂ catalyst was prepared by impregnation reduction method for photocatalytic CO₂ oxidative dehydrogenation of ethane to C₂H₄ at room temperature. Effects of different Pd/Rh ratio of the catalysts on the photocatalytic performances were studied. Morphology characteristics of the catalysts were examined by XRD, EDX-mapping, TEM, HRTEM and XPS. The photocatalytic performances of the catalysts were measured by UV-Vis and PL. The mechanism of oxidative dehydrogenation of ethane was examined with in situ FTIR. The internal electrons transfer between Pd cluster and Rh cluster effectively improves the photocatalytic performance. It reduces the electron density of the Pd surface, and promotes the separation of e^- and h⁺. It also improves the adsorption of C₂H₄ and CO₂ on the surface of the catalyst. The contrast experiments of CO₂ and Ar prove that CO₂ does help to eliminate carbon deposed on the catalyst and to promote ethylene generating with itself reduced by H₂.