Study On The Preparation Of Pt/C And Pt-Au/C Catalysts And Their Catalyzing Oxidation Reaction For Glyoxal

Precious metal nanoparticles have attracted wide attention because of theirunique catalytic characters. However, nanoparticles with uniform shape and size canbe hardly obtained using traditional impregnation method. Nanoparticles weresynthesized firstly and sequently deposired onto activated carbon, then, preciousmetal nanoparticle catalysts were obtained after absorbing, stirring and washingprocedures in this thesis. The oxidation reaction of glyoxal into glyoxalic acid waschosen as target reaction to value the catalytic activity of catalysts prepared.For single Pt/C catalyst, the effect of concentration of Pt precursor, kinds ofprotective agents, reducing agents and catalytic actived carbon supporters oncatalytic activity was investigated, and the catalyst with best performance wasselected by screening.For bimetallic Pt-Au/C catalyst, the effect of preparation methods ofnanoparticals, the mass of Pt-Au, kinds and concentration of protective agents, etc.was investigated and the catalytic results were analysed and the reaction mechanismwas discussed.Based on the current analytic technique, further improvements were achieved toanalyze kinds of species in the catalytic production.The main results are outlined as follows:1、The1.0%Pt/C catalyst has the best catalytic activity and selectivity whichprepared via depositing nanoparticles which using H2PtCl6as precursor, PEG-400asprotective agent, NaBH4as reducing agent onto un-treated domestic coconut shellactived carbon(YHB). Under the perfect reaction conditions, the conversion ofglyoxal was93.18%, the yield of glyoxalic acid reached66.88%, while theselectivity reached71.77%after reacting for60min.2、The Pt-Au/C bimetallic catalysts prepared via photochemical reductionmethod has better catalytic activity than Pt-Au/C bimetallic catalysts prepared viachemical reduction method. Among them, catalyst with the ratio of Pt:Au=4:1which using photochemical reduction method in acetone-PEG system has the best catalyticperformance. The yield of glyoxalic acid reached61%.3、 The analysis of the formic acid was solved using improvedspectrophotometric method. The amounts of formic acid in all catalytic reactionproduction were all less than5%.