Biomolecule-mediated Growth Of Nanoparticles And Their Catalytic Performance

The combination of biotechnology and nanotechnology is a research hotspot in the field of materials at the present stage,especially the biological molecules have great advantages and potential in regulating the growth of nanoparticles?NPs?,improving the physical and chemical properties of NPs and expanding new applications.In this research,Pt,Pd and CeO₂ NPs were synthesized using biological molecules as templates and their applications in redox reactions were explored.Firstly,glutathione?GSH?and cysteine?Cys?were used as templates to control the growth of Pt NPs on graphene nanoplates?GNPs?.On the carrier interface,Pt NPs were prepared by the synergistic effect of biomolecules and GNPs.Compared with Pt/GNPs without template assisted,Pt NPs in Pt-GSH/GNPs and Pt-Cys/GNPs are highly dispersed and exhibit higher catalytic performance in methanol electrooxidation and its catalytic performance is closely related to the type of modified functional groups,the size and morphology.In general,catalysts obtained by interface control method show higher catalytic performance than that of catalysts obtained by non-interface control method,especially at the[K₂PtCl₄]/[Cys]ratio of 24,nonspherical Pt-Cys/GNPs with the length of 3¹3 nm have the highest mass activity(695.04 A g^-1),which is 2.15-times higher than Pt/GNPs,and also own good stability and anti-CO poisoning ability.Secondly,histidine?His?was selected as biotemplate to regulate the synthesis of CeO₂ NPs.The obtained His-CeO₂ has higher surface oxygen vacancy than pure CeO₂.Then Pt/His-CeO₂-C is synthesized with His-CeO₂ as a cocatalyst component.Depending on the synergistic effect between Pt and His-CeO₂,Pt/His-CeO₂-C has better catalytic performance in the methanol electrooxidation and the the mass activity reaches 1116.9 A g^-1,which is 2.94-times higher than Pt/C-Z obtained without oxide assisted,2.19-times higher than the commercial Pt/C-JM and higher than Pt/CeO₂-C(765 A g^-1).In addition,CO stripping experiments prove that the presence of oxygen vacancy in His-CeO₂ has played an important role in improving its anti-CO poisoning ability and improving the catalytic properties of catalysts.Finally,high-density defects and grain boundaries on CoA-Pd NPs were synthesized by coenzyme A?CoA?as biotemplate in aqueous phase.Among them,CoA-Pd?1:45?NPs shows the highest catalytic effect for the reduction of Cr?VI?by using formic acid?FA?as the reductant with the highest reduction rate of 2.45 mmol mg^–1 min^–1?50 ^oC?,which is superior to recently reported Pd-based catalysts.Experimental characterizations and DFT calculations disclose that functional groups at both ends of the CoA are the main sites for the nucleation and growth of Pd,so the way Pd tends to grow at both ends of chain molecules is beneficial to form lots of grain boundaries and defects,and the existence of these defects is the key factor in improving catalytic activities.In addition,CoA-Pd NPs with FA also have good application in the catalytic reduction of 4-nitrophenol?4-NP?and dechlorination of trichloroethylene?TCE?.The above results provide a reference for synthesis of highly efficient nanomaterials mediated by biotemplates for redox reaction.