Electrodeposited PtNi nanoparticles towards oxygen reduction reaction: A study on nucleation and growth mechanism

In this work, highly monodispersed Pt-Ni alloy nanoparticles were directly deposited on carbon substrate through a facile electrodeposition strategy in the solvent system of N,N-dimethylformamide (DMF). A series of carbon supported Pt-Ni alloy electrocatalysts were synthesized under different applied electrode potentials. Among all as-obtained samples, the Pt-Ni/C electrocatalyst deposited at -1.73 V exhibits the optimal specific activity up to 1.850 mA cm(-2) at 0.9 V vs. RHE, which is 6.85 times higher than that of the commercial Pt/C. Comprehensive physiochemical characterizations and computational evaluations via density functional theory were conducted to unveil the nucleation and growth mechanism of PtNi alloy formation. Compared to the aqueous solution, DMF solvent molecule must not be neglected in avoiding particle agglomeration and synthesis of monodispersed nanoparticles. During the alloy co-deposition process, Ni sites produced through the reduction of Ni(II) precursor not only facilitates Pt-Ni alloy crystal nucleation but also in favor of further Pt reduction on the Ni-inserted Pt surface. As for the deposition potential, it adjusts the final particle size. This work provides a hopeful extended Pt-based catalyst layer production strategy for proton exchange membrane fuel cells and a new idea for the nucleation and growth mechanism exploration for electrodeposited Pt alloy. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

By directly depositing highly monodispersed Pt-Ni alloy nanoparticles on a carbon substrate through electrodeposition and synthesizing carbon supported Pt-Ni alloy electrocatalysts under different applied electrode potentials, an optimal specific activity was achieved for the Pt-Ni/C electrocatalyst deposited at -1.73 V, showing potential for proton exchange membrane fuel cells.