The Effect of Reducing Agents on the Electronic, Magnetic and Electrocatalytic Properties of Thiol-Capped Pt/Co and Pt/Ni Nanoparticles

The electronic, magnetic and electrocatalytic properties of bimetallic thiol-capped Pt/Co and Pt/Ni nanoparticles were synthesised using two reducing agents, NaBH4 and N2H4. X-ray diffraction analysis of the nanoparticles showed Pt lattice contraction upon the addition of Co or Ni to Pt indicating the formation of an alloy structure, more apparent when N2H4 was used. XPS data analysis revealed Pt metal and Pt(II) (assigned to PtO) and a higher concentration of surface metallic Ni and Co for the NaBH4-reduced samples. Both the NaBH4- and N2H4-reduced catalysts were active for the methanol oxidation reaction (MOR), with the Pt-Co-N2H4 catalyst revealing the highest activity. The N2H4 significantly affected the magnetic properties of Pt/Co and Pt/Ni particles by controlling the morphology and crystalline structure of the nanoparticles. In general, the type of reducing agent affected the final properties of the nanoparticles.