In this letter, we report a quantitative analysis of how a Pt（II） precursor is reduced to atoms at different temperatures for the formation of Pt nanocrystals with different morphologies and sizes. Our results sugge...In this letter, we report a quantitative analysis of how a Pt（II） precursor is reduced to atoms at different temperatures for the formation of Pt nanocrystals with different morphologies and sizes. Our results suggest that in the early stage of a synthesis, the Pt（II） precursor is reduced to atoms exclusively in the solution phase, followed by homogeneous nucleation to generate nuclei and then seeds. At a relatively low reaction temperature such as 22℃, the growth of the seeds is dominated by autocatalytic surface reduction that involves the adsorption and then reduction of the Pt（II） precursor on the surface of the just-formed seeds. This particular growth pathway results in relatively large assemblies of Pt nanocrystals. When the reaction temperature is increased to 100 ℃, the dominant reduction pathway will be switched from surface to solution phase, producing much smaller asselnblies of Pt nanocrystals. Our results also demonstrate that a similar trend applies to the seed-rnediated growth of Pt nanocrystals in the presence of Pd nanocubes.展开更多
基金supported in part by a grant from National Science Foundation of the United States(DMR-1505441)startup funds from the Georgia Institute of Technology
文摘In this letter, we report a quantitative analysis of how a Pt（II） precursor is reduced to atoms at different temperatures for the formation of Pt nanocrystals with different morphologies and sizes. Our results suggest that in the early stage of a synthesis, the Pt（II） precursor is reduced to atoms exclusively in the solution phase, followed by homogeneous nucleation to generate nuclei and then seeds. At a relatively low reaction temperature such as 22℃, the growth of the seeds is dominated by autocatalytic surface reduction that involves the adsorption and then reduction of the Pt（II） precursor on the surface of the just-formed seeds. This particular growth pathway results in relatively large assemblies of Pt nanocrystals. When the reaction temperature is increased to 100 ℃, the dominant reduction pathway will be switched from surface to solution phase, producing much smaller asselnblies of Pt nanocrystals. Our results also demonstrate that a similar trend applies to the seed-rnediated growth of Pt nanocrystals in the presence of Pd nanocubes.
