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Study On Catalytic Performance Of Nano-Gold And Zeolite System

Posted on:2007-04-04Degree:MasterType:Thesis
Country:ChinaCandidate:X X LiFull Text:PDF
GTID:2121360185986324Subject:Environmental Science
Abstract/Summary:PDF Full Text Request
A series of gold catalysts for CO oxidation was prepared by deposition precipitation method and organic gold-complex grafting method with gold as active site and 13X zeolite as support. The catalytic activity for CO oxidation was evaluated by gas chromatogram under CO concentration of 2500ppm. The means of XRD, XPS, SEM and BET were used to characterize these catalysts; the factors affecting the activity of catalysts and the reactive mechanism were discussed.The experiment showed that gold catalysts prepared by deposition precipitation method when the gold concentration around 0.0097 mol/L, the pH value of chloroauric acid solution at 8, solution temperature at 80℃, the calcination temperature at 300℃, the activity of Au/13X was better. When the catalyst temperature was 120℃, GHSV=12000h-1, CO could turn to CO2 entirely.The experiment showed that the catalysts prepared by organic gold-complex grafting method when the stiring time at 2h, the calcination temperature at 300℃, calcination time at 4h, the activity of Au/13X was better, but was worse compared with the former, T50 was above 300℃.The activity of gold catalysts for CO oxidation was different by preparation method; this could show that the gold state, the size of gold particle, the nature of support, and the property of gold-support could influence the activity of catalysts. From SEM and BET results, it was found that Au/13X prepared by deposition precipitation, has large surface area and good gold distribution on the support surface. And its mean aperture was 3 nm. From XPS and XRD analysis, it was estimated that Au0 may be the active species of Au support catalysts and the existence of Au3+ may improve the catalytic performance. There was some synergetic effect between the two species of Au.In this paper Au/13X catalysts were prepared by two methods with gold as active site and 13X zeolite as support, and studied the catalytic performance for CO oxidation, this study were not only enriching the theory of gold catalyst but also exploiting a new catalyst, in addition these gold catalysts as new catalysts offered new choose and new technology approach for environmental protection.
Keywords/Search Tags:Gold, Zeolite, CO, Catalytic oxidation
PDF Full Text Request
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