Pd@PtRuNi core–shell nanowires as oxygen reduction electrocatalysts

Fuel cells, as the alternative to fossil energy, have engaged widespread attention by reason of the high conversion efficiency from the chemical energy to the electric energy combined with low pollution emissions. The cathodic ORR catalysts with excellent performance and cost-effectiveness are the dominant point towards the massive development of fuel cells. Here, our group select the Pd NWs as the template and construct the Pd@PtRuNi core–shell bilayer nanostructure to expand platinum atom utilization. Pd@PtRuNi bilayer core–shell NWs unfold elevated mass activity of 1.62\,{\rm{A}}\,{{\rm{mg}}}_{{\rm{metal}}}^{-1} at 0.9 V versus RHE in alkaline media, 2.03- and 6.23-fold of pristine Pd NWs and benchmark commercial Pt/C, respectively. Meanwhile, the cyclic stability tests reveal the excellent durability of Pd@PtRuNi NWs, whose mass activity is only 13.58% degradation after accelerated durability tests. The catalytic activity and durability towards ORR are better than the U.S. 2025 DOE target (0.44\,{\rm{A}}\,{{\rm{mg}}}_{{\rm{pt}}}^{-1} and less than 40% activity attenuation at 0.9 V after 30 000 potential cycles). The elevated catalytic properties can be traceable to the synergism between the ligand effect of Ni and Ru and one-dimensional structure superiority, which optimizes the electronic structure of active sites, promotes the charge transfer and restrains the agglomeration and detachment.