Study On Preparation Of Modified Bentonite And Its Supporting Nicle Catalysts For Benzene Hydrogenation

Gold nanoparticles are highly active for low-temperature CO oxidation, gold catalysts have been widely studied. The syntheses of gold nanoparticles supported on a variety of metal oxides, have been reported. Au/SiO2, however, is not active for CO oxidation. The bentonie is a kind of clay which is cheap and easy to get. Montmorillonite is the main mineral component of it. The montmorillonite has good ability of swelling, cation exchange, water absorption, thixotropy, adhesion, adsorption. It can be a good catalyst material for its valuable ability. Now, there is no report for Au supported on the bentonie. In this paper, we prepared Au catalysts supported on modified bentonite and investigated their catalytic performance for CO oxidation. The influence of the type and strength of acid for support,the prepare method, the different loading of Au, the calcination temperature and adsorption time is studied.The Au and Au-Ce catalyst is prepared and compared its catalytic properties by CO oxidation. These samples were characterized by BET, XRD, ICP, CO-TPD and TEM.1. The bentonie which is acid-activated by HC1 and H2SO4 was used as the support of catalyst. To prepare the catalyst by impregnation, deposition-precipitation and cation adsorption. To investigate the influence of method, support, adsorption time and calcination temperature by comparing the CO oxidation. The results show that the surface area and pore volume of bentontie has significantly increased after activated by acid. The effect actived by H2SO4 was more significant than HC1. The prepare methods have a great impact for the catalytic properties of catalyst. The catalyst prepared by CA method have better activity than others. At the same conditions of theory Au loading and test condition, the catalyst prepared by CA method can achieve complete conversion at 210℃. Among the support of LBen, YBen and SiO2, Au supported on acid-actived bentonie have better activity than Au/ SiO2,Au/LBen was more active than Au/YBen at the same Au loading which was proved by TEM. The catalyst supported on bentonie acid-actived by H2SO4 and prepared by CA was use to investigate the influence of calcination temperature and adsorption time. The result shows that adsorption for 48h and calcination at 450℃can get the catalyst with best activity.2. Choose the bentonie acid-actived by H2SO4 as the support of catalyst which was prepare by deposition-precipitation. Study the influence of the strength of acid, Au loading for CO oxidation. The catalytic activity is investigated over Au-Ce/LBen, Au/LBen and Au/SiO2. The results show that The surface area of sample can maximum to 341m2.g-1 after activated by appropriate acid concentration30%(wt.). So,choose the 30%LBen as the support of catalyst. The catalytic activity was first increased and then decreased with the increase of Au loading. It can achieve the best activity at 2.5wt%. The Au-Ce/LBen catalyst shows best catalytic activity. CO is completely conversed at 270℃.The Au-Ce/LBen have better CO adsorption ability and heat stability.