Laser Processed Magnetite Nanoparticles Embedded on rGO Composites for Efficient Electrocatalytic Oxygen Evolution Reaction

The oxygen evolution reaction (OER) plays a key role in the ongoing global search for effective and clean energy sources. Tremendous efforts have been devoted to finding high-performance electrocatalysts consisting of nonprecious metals. The search is spent, not only on the designing of new materials, but also on the invention of new fabrication techniques. Recently, laser processing has emerged as a promising route to obtain micron-thick films of highly graphitic carbons. The laser approach enables a fast one-step synthesis of highly-dispersed nanoparticles under ambient temperature and pressure conditions. In this work, a laser is used to fabricate magnetite/reduced graphene oxide (rGO) composite electrodes as electrocatalysts. The graphitization level can be controlled by tuning different laser parameters. The detailed chemical, structural and morphology characterization, and electrochemical measurements are investigated. With only five atomic percentage metal, the designed magnetite-rGO electrocatalyst lowers the overpotential by 40 mV at 10 mA cm(-2) with a smaller Tafel value (63 mV dec(-1)). Moreover, these studies demonstrate that magnetite-rGO nanocomposites are stable OER electro- catalysts with only 13.5% activity reduction after 10 h of chronoamperometric operation. This work combines an efficient nanocomposites fabrication method with important implications for energy-related applications.