Controlled preparation and application of glutathione capped gold and platinum alloy nanoclusters with high peroxidase-like activity

Abstract

• The Au-PtNCs have been controlled prepared through a hydrothermal method. • The Au-PtNCs show optimal catalytic activity for TMB oxidation. • Doping with platinum is the most efficient way to improve the catalytic properties. • The Au-PtNCs are applied to colorimetric determine H 2 O 2 with high sensitivity. In the present study, we have prepared glutathione capped gold and platinum alloy nanoclusters (Au-PtNCs) in a controlled way by employing the hydrothermal method and optimized through adjusting the ratio of raw materials, reaction temperature, and time. Compared with the corresponding monometallic gold and platinum nanoclusters, the alloy nanoclusters' catalytic activity is improved dramatically in the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 . And the maximum velocity is calculated to be 106 × 10 −8 M · s −1 for TMB as substrate, being much better than that of other reported metallic nanoclusters and nanoparticles. Further study shows that the high catalytic activity mainly attributes to the synergistic effect of gold and platinum. Besides, they have been applied to determine H 2 O 2 in the presence of TMB, which shows high sensitivity with a limit of detection (LOD) at 100 nM. The proposed method has been used to determine H 2 O 2 in milk and contact lens solutions, which shows very good recovery and exhibits high practical application potential. Therefore, the present study provides a new type of alloy nanoclusters with high peroxidase-like activity, which will inspire more research interests on doping and alloying with Pt to improve the catalytic activity of metal nanoclusters.