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以溶胶-凝胶法制备TiO2载体,用沉积-沉淀法制备出一系列负载型Au/TiO2。系统考察了焙烧温度、金的负载量、反应液pH值、沉淀剂种类以及Cl-存在与否等制备参数对催化剂活性的影响。以室温下CO的催化氧化为探针反应,确定催化剂的最适宜制备参数,并对优化的质量分数为1.0%的Au/TiO2催化剂进行了活性稳定性测试。结果表明:Au/TiO2的最适宜焙烧温度是200～350℃;反应液的最适宜pH值为9;最适宜沉淀剂是NaOH;金的负载量(质量分数,下同)在0.5%～5.0%范围内时,金含量越高,催化剂活性和热稳定性越好。大量Cl-的存在能导致催化剂活性的显著下降。对优化的Au/TiO2催化剂在室温下催化氧化不同浓度的CO进行循环测试,经历3次循环,连续反应2 160 min后,CO的转化率仍为100%。
The TiO2 carrier was prepared by sol-gel method and a series of supported Au / TiO2 were prepared by deposition-precipitation method. The effects of calcination temperature, loading of gold, pH value of the reaction solution, precipitant type and presence of Cl- on the activity of the catalyst were systematically investigated. Catalytic oxidation of CO at room temperature was used as a probe reaction to determine the most suitable preparation parameters of the catalyst. The activity stability of Au / TiO2 catalyst with 1.0% mass fraction was tested. The results showed that the optimum calcination temperature of Au / TiO2 was 200-350 ℃, the optimum pH value of the reaction solution was 9, the most suitable precipitating agent was NaOH, and the loading of gold (mass fraction) was between 0.5% and 5.0% % Range, the higher the gold content, the better the catalyst activity and thermal stability. The presence of large amounts of Cl- can lead to a significant decrease in catalyst activity. The optimized Au / TiO2 catalyst was tested for catalytic oxidation of different concentrations of CO at room temperature. After 3 cycles, the CO conversion was still 100% after 2 160 min continuous reaction.