Monolithic electrode integrated of ultrathin NiFeP on 3D strutted graphene for bifunctionally efficient overall water splitting

High-performance earth-abundant electrocatalysts for oxygen and hydrogen evolutions are highly desired for renewable energy but remain challenging. Herein, we have developed ultrathin NiFeP nanosheets, and merged the NiFeP with a 3D support of sponge-like strutted graphenes (SG). The synthesized NiFeP/SG, a porous monolith, shows efficient electrocatalytic activities for oxygen and hydrogen evolutions in alkaline electrolyte with low overpotentials of 218 and 115 mV, respectively. Using NiFeP/SG as direct catalytic electrodes, the overall water splitting requires a low cell voltage of 1.54 V to achieve a current of 10 mA cm−2. The high performances result from the shifted-up d states caused by iron incorporation, the ultrathin NiFeP, and the 3D network structure of SG. Additionally, NiFeP/SG demonstrates excellent gravimetric catalytic activities, meaningful to aerospace and portables. The material opens the way to a universal robust lightweight catalytic electrode for a variety of applications in electrochemical energy storage and conversion.