Laser assisted solution synthesis of high performance graphene supported electrocatalysts

Simple, yet versatile, methods to functionalize graphene flakes with metal (oxide) nanoparticles are in demand, particularly for the development of advanced catalysts. Herein, based on light-induced electrochemistry, we report a laser-assisted, continuous, solution route for the simultaneous reduction and modification of graphene oxide with catalytic nanoparticles. Electrochemical graphene oxide (EGO) was used as tarting material and electron-hole pair source due to its low degree of oxidation, which imparts structural integrity and an ability to withstand photo-degradation. Simply illuminating a solution stream containing EGO and metal salt (e.g. H2PtCl6 or RuCl3) with a 248 nm wavelength laser produced reduced EGO (rEGO, oxygen content 4.0 at.%) flakes, decorated with Pt (~2.0 nm) or RuO2 (~2.8 nm) nanoparticles. The RuO2-rEGO flakes exhibited superior catalytic activity for the oxygen evolution reaction, requiring a small overpotential of 225 mV to reach a current density of 10 mA cm−2. The Pt-rEGO flakes (10.2 wt.% of Pt) shows enhanced mass activity for the hydrogen evolution reaction, and similar performance for oxygen reduction reaction compared to a commercial 20 wt.% Pt/C catalyst. This simple production method was also used to deposit PtPd alloy and MnOx nanoparticles on rEGO, demonstrating its versatility in synthesizing functional nanoparticle modified graphene materials.