A Large-Scale Graphene–Bimetal Film Electrode with an Ultrahigh Mass Catalytic Activity for Durable Water Splitting

The practical industralization of water splitting needs high-efficient and cost-effective catalytic electrodes. A versatile and scalable solution-processing method to prepare such a catalytic electrode with high flexibility and conductivity is introduced. This preparation method is applicable for a wide variety of metal species and takes graphene sheets as metal carriers and film-forming agents, resulting in 100% utilization of raw materials. The obtained graphene–bimetal film has excellent comprehensive performance with high areal activity and superior turnover frequency at a low mass loading of 0.05 mg cm⁻², as well as a record-high mass activity for oxygen or hydrogen evolution. The assembled two-electrode configuration can be used in a practical full water splitting system, requiring a cell voltage of 1.58 or 1.50 V at 30 or 70 °C to afford a current density of 10 mA cm⁻²; it also exhibits a long-term durability over 200 h, superior to most of the reported systems for the same purpose. This work provides a new platform for large-scale and high-yield production of electrocatalysts and also uncovers the design principles of catalytic electrodes with high mass activity toward industralization.