Halide-regulated growth of electrocatalytic metal nanoparticles directly onto a carbon paper electrode

Direct growth of hierarchical micro/nanostructured metal arrays on a 3D substrate is a powerful tool to enhance the catalytic efficiency of metal particles towards a wide range of substrates. In this contribution, we demonstrate a novel and versatile method for growing anisotropic microstructures directly onto a 3D carbon paper electrode, using Au, Pd and Pt nanoparticles as elementary building blocks. It was determined that halides play a crucial role in the morphology of synthesized Au particles, leading to either complex flower-like rough surfaces (exhibiting high catalytic activity) or featureless smooth surfaces (exhibiting low catalytic activity). Of the three metal materials studied, the Pt decorated carbon paper (Pt@carbon) material exhibits a high electrocatalytic activity toward the oxygen reduction reaction in an alkaline medium. We demonstrate that this new Pt material can operate as a cathode in an alkaline glucose fuel cell exhibiting outstanding peak power density of 2-3 mW cm(-2) (using an anode of Au@carbon or Pt@carbon at room temperature and low metal loading without any fuel circulation). This newly described fabrication approach allows for the rational control of metallic particle growth, paving a new way towards materials with regulated surface roughness allowing for tuneable physical, optical and catalytic properties.