摘要
采用红外光谱研究了CO在担载于Al_2O_3上的氧化态和还原态Pd与Pt及Pd-Pt双金属催化剂上的吸附态和吸脱附行为。吸附速度和升温脱附试验结果表明,CO在担载Pd上先出现桥式吸附态而后出现线式吸附态,前者不易脱附而后者极易脱附。CO在PdO上的吸附趋于饱和时,出现1995cm^(-1)的弱吸收带。CO在担载Pt上以线式吸附态为主而不易脱附。在Pd-Pt双金属催化剂上CO的吸脱附行为与Pd/Pt比有着密切关系。讨论了氧化作用、Pd/Pt比对CO吸脱附性质的影响。
The adsorption and stepwise desorption of CO and the adsorbed Species of CO on the oxidized and reduced alumina-supported Pd, Pt and Pd-Pt bimetallic catalysts have been studied by in situ IR spectroscopy. When CO is adsorbed on Pd/Al2O3, the linear CO species appear behind the predominant bridged species, the former can be easily desorbed even by evacuation; at full surface co-verage by CO, a new weak band appears at about 1995 cm-1. On the contrary, when CO is adsorbed on Pt/Al2O3, the linear CO Species holds a dominant position, and is difficult to be desorbed. The behavior of adsorption and desorp-tion of CO on Pd-Pt/Al2O3 catalysts with different Pd/Pt ratios is obviously different. The effects of oxidation, and Pd/Pt ratio on the behavior of CO ad-sorption and dcsorption are discussed.
基金
国家自然科学基金
