A research team has created an electrode for hydrogen evolution. A nickel-molybdenum (NiMo) catalyst is wrapped in a ‘holey’ graphene layer containing nanometer-sized holes. The fringes of the holes are chemically active sites, boosting hydrolysis by accelerating charge transfer and H atom adsorption. Meanwhile, graphene protects the NiMo core from dissolving. Through efficient hydrogen generation in acid solution using non-noble metals, the system potentially allows affordable green energy storage.