富氧条件下Au/γ-Al_2O_3催化剂上的CO氧化反应

The CO Oxidation on Au/γ-Al_2O_3 Studied by Pulse Reaction Technique

用脉冲反应研究了Au/γ-Al2O3催化剂上的CO氧化反应,结果表明在催化剂的表面首先发生CO和O2的吸附,然后吸附态的CO和O2之间反应生成CO2;在催化剂的表面CO的吸附强度大于O2的吸附强度,O2单独存在时不能在催化剂表面发生吸附.升高反应温度和提高含氧量都能提高CO的转化活性.

The reaction mechanism of CO oxidation on Au/γ-Al_2O_3 as well as the effect of reaction conditions on the CO conversion has been investigated using pulse reaction method. The catalyst was prepared by a deposition-precipitation method in an HAuCl_4 solution using γ-Al_2O_3 as support, the loading of Au was 2%. According to the test results, a mechanism of CO oxidation on Au/γ-Al_2O_3 catalyst was assumed as follows: first CO adsorbed on the Au surface forming Au-CO species, then the O_2 in the gas phase may be directly activated on the surface of the Au atoms around the Au-CO species and then reacted with the adsorbed CO to form CO_2. In the case of O_2 existed in the gas phase alone, it cannot adsorbed on the surface of the catalyst. Composition of reactants and reaction temperature has evident effect on the CO conversion.