Preparation Of Supported Nano-metal Catalyst And Its Catalytic Performance For WGSR

In the thesis, a series of Ru-based and Au-based catalysts were prepared, which supportedon MgAl₂O₄ spinel and promoted by alkali-metal oxide and/or rare-earth oxide. Catalysts werecharacterized by means of TEM, SEM, XRD, BET, UV-vis technique, and on which the WGSreaction activity evaluation was performed.(1) RuO₂ nanoparticles with an average diameter of 4.9 nm were prepared using thesol-gel method, and then the nanoparticles were embedded in MgAl₂O₄ as the support. PVAwas introduced in the preparation in order to inhibit RuO₂ particle agglomeration and make themicro-path where reactants contact with catalyst. The catalyst was good at anti-sinteredbecause the particles were embedded in the support. And the steady catalytic activity wasobtained also.(2) Gold sol was prepared by sol method and then supported on MgAl₂O₄ spinel. A groupof Au-based catalysts were prepared with CeO₂ and K₂O as promoters. The results ofevaluation represented that Au loading and the promoters were key factors for the catalyticactivity. Au/CeO₂ catalyst was also studied as a contrast, and the CO conversion was up to 90%when the temperature was 300℃.(3) Effect of particle size on Ru-based and Au-based catalysts were studied. The resultindicated that the catalytic activity increased along with the decreasing of nanoparticle sizebecause of the quantum size effect resulting from size decreasing of nano-metal. The numberof surface atom increase heavily that will change bond state between reactant and nano-metal,and the number of active site also increase heavily. In Ru-base and Au-based catalysts, catalystwith 2.6nm Ru or 4nm Au displayed the best catalytic activity respectively.