Synthesis And Property Of Novel Supported Metal Oxide Nanoparticles Catalysts

The gases emitted by modern industries and mobiles contain large amounts of CO₂ and volatile organic compounds?VOCs?.CO₂is the main cause of greenhouse effect.Therefore,reducing CO₂ emissions and improving the CO₂ utilization have attracted increasing interests.CO₂ methanation is one of the integrated alternatives of CO₂utilization.Meanwhile,most VOCs pollute the environment,and endanger human health.Therefore,it is of great significance to eliminate VOCs.Catalytic oxidation of VOCs is one of the most effective ways to VOCs elimination.The core of CO₂ methanation and VOCs catalytic oxidation is the design of catalysts with excellent activity and stability.In this paper,a novel nickel-based catalyst?nickel species nanoparticles anchored on the layered Si O_x matrix?and a novel noble metal platinum supported catalyst?Pt nanoparticles supported on the amorphous titanium oxide?were designed and prepared.At the same time,the synthesis process and catalytic performance were explored.Firstly,this paper has studied the CO₂ methanation on a Ni-based catalyst.Compared to noble metals such as Ru and Rh,Ni is cheap and has good catalytic activity,and has a prospect of practical large-scale production.Nickel silicate hydroxide has a typical layered structure,and the nickel content is uniformly anchored on the layered Si O_x matrix.The layered structure is beneficial to increase the specific surface area and promote the adsoption and chemical activation of the reactant at the nickel active sites.Therefore,nickel silicate hydroxide is a good nickel-based catalyst precursor.In this paper,by reducing the nickel silicate hydroxide,a catalyst with a high diepersion of nickel species anchored on the Si O_xmatrix was obtained.The optimized Ni/Si O_x-2 catalyst has a high specific surface area(up to 286.4 m² g^-1)and exhibits excellent CH₄ selectivity?91.4%?,CO₂ conversion?64.2%?and thermal durability for CO₂ methanation.Secondly,this paper has studied the catalytic oxidation of VOCs on a Pt-based catalyst.Based on the previous study of the amorphous metal oxide by precipitation-hydrolysis,amorphous titanmiun oxide was synthesized.The catalysts supported platinum nanoparticels obtained by the traditional impreganation methods show excellent catalytic activity for the catalytic oxidation of VOCs under mild condictions.The amorphous phosphorus-doped titanium oxide exhibits high BET surface area?27 times higher than that of initial titanium dioxide?and excellent thermal stability.The platinum nanoparticles?average diameter 1.8±0.5 nm?were successfully dispersed uniformly on the amorphous titanium oxide by impreganation.The optimal sample Pt/40-ATO-P catalyst has good performance for catalytic oxidation of toluene,and its T₅₀ and T₉₀?temperature required for conversion of 50%or 90%?are 130 ^oC and 140 ^oC,respectively,both lower than the contral sample Pt/Ti O₂.In addition,the Pt/40-ATO-P catalyst also exhibited good catalytic oxidation properties for other VOCs?benzene,1,3,5-trimethylbenzene,ethyl acetate and n-hexane?.