制备方法对CuO/CeO_2-ZrO_2催化CO低温氧化活性的影响

采用微波加热分解法(一步法)和微波加热处理共沉淀+浸渍法(两步法)制备了CuO/CeO2-ZrO2催化剂,并对其进行了X射线衍射、低温氮气吸附/脱附和程序升温还原等表征,采用色谱流动法考察了催化剂的催化CO低温氧化性能.结果表明,一步法比两步法更有利于使催化剂表面CuO高度分散,CuO与CeO2-ZrO2间的相互作用更强,CuO更容易被还原,从而具有更高的催化CO氧化活性.与CeO2-ZrO2有相互作用的高分散和小颗粒CuO有利于催化剂活性的提高,与CeO2-ZrO2无相互作用的大颗粒CuO对催化剂的活性有抑制作用.

Effect of Preparation Method on the Activity of CuO/CeO2-ZrO2 Catalysts for Low Temperature CO Oxidation

CuO/CeO₂-ZrO₂ catalysts were prepared by microwave heating decomposition (one-step approach) and by microwave heating treatment of co-precipitation followed by impregnation (two-step approach). The catalysts were characterized by X-ray diffraction (XRD), low temperature N2 adsorption/ desorption, and H₂-temperature-programmed reduction (H₂-TPR). The catalytic activities of the catalysts for low temperature CO oxidation were investigated using a microreactor-gas chromatograph. The results showed that the one-step approach was more beneficial to CuO dispersion on the catalyst surface because of a strong interaction between CuO and CeO₂-ZrO₂ and to the improved reducibility of CuO, which resulted in higher catalytic activity. We conclude that finely dispersed and small CuO particles strongly interact with CeO₂-ZrO₂ are responsible for the high catalytic activity toward CO oxidation and that large CuO particles that do not interact with CeO₂-ZrO₂ inhibit the catalytic activity.