Facile synthesis of synergistic δ-MoN/Co@NCA heterostructures for enhanced bifunctional supercapacitor and oxygen evolution performance

Abstract

Owing to their efficient electron transport, pseudocapacitive properties, customizable electronic structures, and thermal and chemical durability, transition-metal nitrides such as MoN as composites with cobalt are essential for energy-storage applications like supercapacitors. However, the challenging processes involved in creating such electrodes, including ammonolysis, chemical vapor deposition, and carbothermal nitridation, are bottlenecks for researchers. This work investigates a simple synthesis technique for creating a hexagonal molybdenum nitride, cobalt, and nitrogen-doped carbon aerogel (δ-MoN/Co@NCA) nanocomposite. δ-MoN/Co@NCA's potential as a supercapacitor electrode and oxygen evolution reaction catalyst is highlighted. The procedure entails nitridation at 700 °C after the creation of a cellulose acetate and cobalt molybdate complex. Co and MoN are effectively encapsulated within a carbon aerogel matrix in the porous, well-defined crystalline structure of the heterostructured δ-MoN/Co@NCA nanocomposite, as evidenced by the XRD, XPS, and HR-TEM results, which improves electrochemical performance. In a half-cell configuration, the material exhibited a specific capacitance of 654 F g−1 at 1 A g−1 with a reversible capacity of 350 F g−1 at 15 A g−1 and a cycling efficiency of 93.6% after 5000 cycles. A δ-MoN/Co@NCA//Activated carbon asymmetric supercapacitor device exhibited a specific capacitance of 144 F g−1 at 1 A g−1. The device showed an 82% capacitance retention after 5000 cycles, with 98% coulombic efficiency. Moreover, the device exhibited energy and power densities of 39.2 Wh kg−1 and 703.4 W kg−1, respectively. The electrodes’ oxygen evolution reaction performance likewise showed a 265 mV overpotential and a 73 mV dec−1 Tafel slope. This study demonstrates that the δ-MoN/Co@NCA nanostructure exhibits synergetic electrochemical properties derived from Co, MoN, and nitrogenated carbon and is an excellent candidate for improving energy storage capabilities in supercapacitors and as an oxygen evolution electrocatalyst. This journal is © The Royal Society of Chemistry, 2026.