Experimental Study On Synthesis And Catalytic Test Of Gold And Ruthenium Nanoparticles

Gold and ruthenium nanoparticles have been widely used in the field of catalysis due to their unique optical,electrical and electromagnetic properties,as well as significant small size effect and surface effect.The size and morphology of the noble nanoparticles and the interactions with carrier are the important factors which affect the catalytic application.Therefore,it is a widely recognized research strategy to fabricate noble metal nanoparticles with various morphologies by liquid phase reduction method and further investigate the immobilization and catalysis in the related fields.This work focuses on in-situ synthesis of gold and ruthenium nanoparticles in liquid phase.The effects and mechanisms of various exogenous substances such as SDS and metal ions on the morphology of gold nanoparticles within the L-tryptophan system and ruthenium nanoparticles within ascorbic acid system were investigated,respectively.Then the graphene oxide with rich functional groups was used as the carrier,and the direct and two-step loading methods were used to support the nanoparticles.Finally,the 4-nitrophenol degradation reaction was catalyzed by each of the nine graphene oxide supported gold and ruthenium nanocatalysts and catalytic effects were compared and analyzed while NaBH₄ as a reducing agent.The results show that chain-like structure gold nanoparticles were synthesized when SDS is present,and gold and ruthenium nanoparticles of various morphologies were synthesized with different exogenous substances.Graphene oxide can achieve fine dispersion of nanoparticles either adopting direct or two-step loading method.Three catalysts immobilized onto graphene oxide are graphene oxide direct reduction catalyst,L-tryptophan and ascorbic acid as reducing agent respectively,and the gold nanoparticles size made by L-tryptophan is in the middle but achieves best catalytic effect among them.Besides,with the addition of PVP,SDS or CTAB,the reaction time is extended.Graphene oxide supported ruthenium nanocatalyst was successfully prepared and applied in the reaction,but the supported ruthenium catalyst with CTAB greatly reduced the catalytic performance.Both supported gold and ruthenium nanocatalysts can be reused after centrifugal separation,and show good catalytic effect while used a second time.