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采用共沉淀法制备了Au/Co_3O_4催化剂,通过TG-DSC、XRD、BET、XPS等技术对其进行了表征,并考察了其室温下催化氧化甲醛的性能.结果表明,Au的负载降低了Co3O4催化氧化甲醛的反应温度,在25℃具有60%的催化去除效率(RH 0%,GHSV 80 000 h-1)和100%的CO2选择性;室内环境湿度水平的水汽能显著提高其催化活性,在25℃达到了95%以上的甲醛去除效率(RH 50%,GHSV 80 000 h~(-1))和100%的CO_2选择性,活性持续2 0 h以上未见降低.XPS结果表明,Au在Co_3O_4表面主要以金属单质形式存在,其引入提高了催化剂表面的Oads/Olatt比.原位红外(In situ DRIFTS)分析结果表明,甲酸盐和二氧亚甲基(DOM)是催化反应过程中的主要中间物种,水汽的引入有利于促进甲酸盐的生成、中间产物的氧化分解以及产物的脱附.
The Au / Co_3O_4 catalysts were prepared by coprecipitation method and characterized by TG-DSC, XRD, BET and XPS, and the catalytic performance of the catalysts for the catalytic oxidation of formaldehyde at room temperature was investigated. The results show that the Au loading decreases the Co3O4 The catalytic oxidation of formaldehyde with 60% catalytic removal efficiency (RH 0%, GHSV 80 000 h-1) and 100% CO2 selectivity at 25 ° C could significantly increase the catalytic activity of formaldehyde at room humidity, 95% formaldehyde removal efficiency (RH 50%, GHSV 80 000 h -1) and 100% CO 2 selectivity reached above 95% at 25 ℃, and the activity did not decrease for more than 20 h. XPS results showed that Au In the surface of Co_3O_4, the metal is mainly in the form of metal element, and its introduction improves the Oads / Olatt ratio of the catalyst surface. In situ DRIFTS analysis shows that formate and dioxomethylene (DOM) The main intermediate species in the introduction of water vapor facilitates the formation of formate, the oxidative decomposition of intermediates and the desorption of products.