In situ surface-doped PtNiCoRh nanocrystals promote electrooxidation of C1 fuels

Abstract

Heteroatom-doped Pt-based nanocrystals have generated considerable interest and hold great prospects in heterocatalysis. However, engineering the superficial atomic configurations of these nanocrystals via in situ surface doping remains exceedingly challenging. Herein, we propose a one-pot, in situ surface doping chemical synthesis protocol to prepare quatermetallic PtNiCoRh dendritic nanocrystals as versatile and active catalysts for the electrooxidation of C1 fuels. Leveraging the selective coordination effect between ascorbic acid and Rh3+ ions, the doping of trace Rh atoms can be guided specifically at the near-surface of PtNiCoRh nanocatalysts. Electrocatalytic tests indicate that Pt67Ni16Co16Rh1 nanocrystals with in situ trace Rh-doped surface exhibit substantially enhanced activity, durability, and CO tolerance for the electrooxidation of methanol, formaldehyde, and formic acid. In situ Fourier transform infrared spectroscopy provides molecular-level insight into the exceptional performance of these nanocatalysts. The surface incorporation of anti-corrosive Rh atoms enables the transfer of CO intermediates from the atop Pt sites to the bridged Rh-Pt surface sites, thereby facilitating the elimination of these poisoning species from the catalyst surface. This study presents an effective in situ surface doping strategy which can enable the design of more atom-economic heterocatalysts.