Ultrathin zigzag-surface copper nanowire assembled hierarchical microspheres to enhance oxygen reduction catalysis.

Ultrathin catalysts predominantly expose surface active atoms to deliver promising applications in oxygen reduction reactions (ORRs). However, they are commonly synthesized at high reaction temperatures, with tedious chemical routes involved. Herein, we report a low temperature (273 K) electric field driven route to synthesize zigzag-surface ultrathin copper nanowires. Interestingly, the ultrathin copper nanowires assemble into three-dimensional microspheres, which exhibit hydrophobic-aerophilic features, eventually resulting in good ORR activities. The aerophilicity and hydrophobicity of copper nanowires are related to their CuO active sites and hierarchical protuberances, respectively. Our findings open a new door to grow ultrathin catalysts for new energy storage systems.