ICS84

H2 evolution studies and effects of alloyed metal composition on Ag-Pt bimetallic nanoparticles as reduction catalysts

Shalaka Varshney 1 Ronen Bar-Ziv 2 Dan Meyerstein 1,3 Tomer Zidki 1
1Department of Chemical Sciences, Ariel University, Ariel, Israel
2Department of Chemistry, Nuclear Research Center Negev, Beer-Sheva, Israel
3Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel

Metallic nanoparticles (NPs) are well established as heterogeneous catalysts and a subject of focus due to their promising use in catalysis.1-3 Herein, we present a kinetic study of reduction reactions on Ag, Au, Pt metallic and Ag-Pt bimetallic alloy NPs that were synthesized in aqueous suspensions without using any stabilizer. Owing to the synergistic and alloying effects between the metals in Ag-Pt alloy NPs, those have shown superior catalytic performance in the reduction of 4-nitrophenol to 4-aminophenol by NaBH4. In the bulk, due to the large immiscibility between Ag and Pt, an alloy has not been observed, whereas in the nanosized regime, the prepared Ag-Pt alloy NPs have not only shown higher catalytic activity than their mono-metals, but also eliminated the induction time which was observed in the pure Ag NPs case. Kinetics studies of hydrogen evolution on various metallic and bimetallic NPs were conducted in order to follow the reduction mechanism of the fastest Ag-Pt catalyst. High-resolution transmission electron microscopy (HR-TEM) and X-Ray powder diffraction (XRD) studies show that the silver-rich Ag-Pt alloy NPs have a spherical linked shape and confirm the structure of an alloy with the size of ~4.0 nm. The highest catalytic activity was gained specifically in one particular metal ratio composition of Ag-Pt alloy NPs with a relatively low content of Pt which also presented those as low-cost catalysts.

REFERENCES

  1. Herves, P., Perez-Lorenzo, M., Liz-Marzan, L. M., Dzubiella, J., Lu, Y., & Ballauff, M. (2012). Catalysis by metallic nanoparticles in aqueous solution: model reactions. Chemical Society Reviews, 41(17), 5577-5587.
  2. Singh, A. K., & Xu, Q. (2013). Synergistic catalysis over bimetallic alloy nanoparticles. ChemCatChem, 5(3), 652-676.
  3. Ferrando, R., Jellinek, J., & Johnston, R. L. (2008). Nanoalloys: from theory to applications of alloy clusters and nanoparticles. Chemical reviews, 108(3), 845-910.








Powered by Eventact EMS