Resource utilization of high concentration SO_(2) for sulfur production over La-Ce-O_(x)@ZrO_(2) composite oxide catalyst

Sulfur dioxide is one of the main causes of air pollution such as acid rain and photochemical smog,and its pollution control and resource utilization become an important research direction of air pollution control,The active component La-Ce-O_(x) is loaded on SiO_(2),γ-Al_(2)O_(3),TiO_(2) and ZrO_(2),and the La-Ce-Ox@ZrO_(2)exhibits the best catalytic activity.By adjusting the loading amount of La-Ce-O_(x),La-Ce-Ox@ZrO_(2) with different mass fractions was prepared.The results show that the activity of 15%La-Ce-Ox@ZrO_(2)catalyst is the best.The SO_(2)conversion is 100%,and the S yield and S selectivity are more than 96% at 350℃.According to the analysis results of H_(2)-TPR,CO_(2)-TPD and NH_(3)-TPD,ZrO_(2) as a support not only reduces the acidity of the catalyst,but also improves the weak alkaline sites of the catalyst,which is conducive to the adsorption and activation of SO2molecules at low temperature.The incorporation of La and Ce increases the oxygen concentration adsorbed on the catalyst.The strong interaction between the support ZrO_(2) and the active component La-Ce-Oxis conducive to the electron transfer between the active component and the support,and improves the activity of the catalyst.For the 15%La-Ce-O_(x)@ZrO_(2),the main reaction intermediates are weakly adsorbed SO_(2)(SO_(3)^(2-)),bicoordinated CO_(3)^(2-),monodentate carbonate and CO in the gas phase.Therefore,the catalytic reaction follows both L-H and E-R mechanisms.