PtNi Nanocrystals Supported on Hollow Carbon Spheres: Enhancing the Electrocatalytic Performance through High-Temperature Annealing and Electrochemical CO Stripping

PtNi nanoparticles have been proved to be a type of highly efficient electrocatalyst for the oxygen reduction reaction (ORR) among the Pt-based nanomaterials. However, how to improve the surface catalytic activity and stability of polymer-stabilized Pt-based nanocrystals is still a critical issue for their application in, fuel cells. In this work, a one-step solvothermal process was used to synthesize PVP-stabilized PtNi nanocubes supported ion hollow carbon spheres. With optimized metal precursor ratio (Pt/Ni = 1:1) and solvothermal temperature (130 degrees C), PtNi nanocrystals with uniform size and cubic shape can be synthesized and highly dispersed on :hollow Carbon spheres. To improve the electrocatalytic activity of the PtNi nanocrystals, the synthesized composite was treated by a heating annealing at 300 degrees C and a subsequent electrochemical CO stripping process. It was found that the two-step treatment can significantly enhance the catalytic activity of the PtNi nanocrystals for ORR with high durability. In addition, the prepared PtNi-composite also showed higher catalytic activity and stability for methanol oxidation. The obtained peak current density on the present catalyst can reach 3.89 A/mg(pt), which is 9 times as high as commercial Pt/C (0.43 A/mg(pt)). The present study not only demonstrates a general method to synthesize hollow Carbon sphere-supported nanoparticle catalysts but also provides an efficient strategy to active the surface activity of nanoparticles.