Efficient Self‐Powered Overall Water Splitting by Ni4Mo/MoO2 Heterogeneous Nanorods Trifunctional Electrocatalysts

Abstract The exploration of cost‐effective multifunctional electrodes with high activity toward energy storage and conversion systems, such as self‐powered alkaline water electrolysis, is very meaningful, although studies remain quite limited. Herein, a heterogeneous nickel‐molybdenum (NiMo)‐based electrode is fabricated for the first time as a trifunctional electrode for asymmetric supercapacitor (ASC), hydrogen evolution reaction, and oxygen evolution reaction. The trifunctional electrode consists of Ni 4 Mo and MoO 2 (denoted Ni 4 Mo/MoO 2 ) with hierarchical nanorod heterostructure and abundant heterogeneous nanointerfaces creating sufficient active sites and efficient charge transfer for achieving high performance self‐power electrochemical devices. The ASC consists of the as‐prepared Ni 4 Mo/MoO 2 positive electrode, showing a broad potential window of 1.6 V, and a maximum energy density of 115.6 Wh kg −1 , while the alkaline overall water splitting (OWS) assembled using the as‐prepared Ni 4 Mo/MoO 2 as bifunctional catalysts only requires a low cell voltage of 1.48 V to achieve a current density of 10 mA cm −2 in aqueous alkaline electrolyte. Finally, by integrating the Ni 4 Mo/MoO 2 ‐based ASC and OWS devices, an aqueous self‐powered OWS is assembled, which self‐power the OWS to generate hydrogen gas and oxygen gas, verifying great potential of the as‐prepared Ni 4 Mo/MoO 2 for sustainable and renewable energy storage and conversion system.