Preparation And Catalytic Performance Of Silica Microspheres Supported Silver,Gold And Platinum Nanomaterials

In recent years,people have become more and more aware of environmental protection,and various materials have been studied for the treatment of environmental pollution caused by various organic dyes and nitro compounds.Noble metal nanomaterials are widely used in the field of catalysis due to their small size and large specific surface area.Among them,silver,gold,and platinum nanomaterials are all promising catalysts in the field of catalysis.As a result,the catalytic performance of the catalyst is reduced,so the supported noble metal nanocatalyst have shown broad application prospects.Among many carriers,silica exhibits excellent characteristics.Because bimetallic nanocatalysts usually produce synergistic effects and show better catalytic performance than single-metal catalysts,the preparation of bimetallic catalysts has become one of the hotspots of research in recent years.The main content and results of the paper are as follows:（1）On the basis of the previous work,this thesis uses the hydrolysis and condensation reaction of 3-mercaptopropyltrimethoxysilane（MPTMS）to modify the surface of silica with sulfhydryl functional groups,and use sulfur dioxide modified with sulfhydryl functional groups.Silicon is used as a carrier to prepare Ag and Au nanocomposite materials supported on a silica carrier.Exploring the catalytic performance of composite materials,when catalytic reduction of p-nitrophenol（4-NP）,the catalytic activity of supporting bimetallic Ag and Au ratio of 1:2 is better.In the catalytic reduction of methine blue（MB）,the catalytic activity of which the ratio of Ag to Au is 1:4 is the best compared to other catalysts.In the catalytic reduction of p-nitrothiophenol（4-NTP）,the catalytic activity is the best when the ratio of bimetallic Ag and Au is 1:1.（2）Silica modified with sulfhydryl functional groups is used as a carrier to prepare Ag and Pt nanocomposite materials supported on a silica carrier.Exploring the catalytic performance of the composite material,in the catalytic reduction of 4-NP,the catalytic effect of loading Ag and Pt ratio of 1:1 is the best,which is better than other catalysts.In the catalytic reduction of MB,when the ratio of Ag to Pt is 1:2,the catalytic activity is the best compared with other catalysts.In the catalytic reduction of 4-NTP,the catalyst with a ratio of 1:1 between Ag and Pt has a fast reaction rate during the period of time when the reaction starts,but as time goes by,the reaction rate gradually decreases.（3）Several magnetic supported catalysts that can be quickly separated and recovered,Fe₃O₄@Si O₂,Fe₃O₄@Si O₂@Ag,Fe₃O₄@Si O₂@Au and Fe₃O₄@Si O₂@Ag-Pt were prepared,and the catalytic performance of several catalysts was explored.In the catalytic reduction of4-NP,Fe₃O₄@Si O₂@Ag and Fe₃O₄@Si O₂@Ag-Pt have better catalytic performance.In the catalytic reduction of MB,the Fe₃O₄@Si O₂@Ag-Pt bimetallic catalyst has the best catalytic performance,and in the catalytic reduction of 4-NTP,Fe₃O₄@Si O₂@Ag shows better catalytic performance.The reusability of Fe₃O₄@Si O₂@Ag catalyzed by 4-NP reduction was explored,and it still has good catalytic activity after multiple cycles of continuous catalysis.