Construction of NiSe2/Ni3B2O6 heterostructures on electrospun carbon nanofibers for high-performance supercapacitor and hydrogen evolution reaction

Heterostructured engineering is driving advancements in supercapacitor and hydrogen evolution reaction (HER). In this work, a NiSe2/Ni3B2O6 heterostructure on electrospun carbon nanofibers was fabricated as a dual-functional material. The NiSe2/Ni3B2O6 heterojunction with favorable electronic distribution and the well-dispersed active sites supported by electrospun carbon nanofibers, facilitate conductivity, stability and reaction kinetics. CCo@NiSe@NiBO, belonging to an energy storage mechanism dominated by diffusion control, showed a specific capacitance of 984.0 F g-1, and a capacitance retention of 42.68% when the current density increases by 20 times, which exceeds that of many reported Ni based selenides and borides. Meanwhile, CCo@NiSe@NiBO as a HER catalyst achieved overpotentials of 227 mV at 10 mA cm-2 and Tafel slopes of 91.2 mV dec-1. DFT calculations revealed its optimized adsorption energy of OH- for CCo@NiSe@NiBO. In addition, a CCo@NiSe@NiBO//active carbon hybrid device displayed an energy density of 35.58 Wh kg-1 as well as 91.88% of its initial capacitance after 10000 cycles. It was successfully integrated into the circuit. This work emphasizes the advantages of electrospun nanofibers in constructing heterostructures and establishes heterostructured engineering as a powerful strategy for advancing energy storage devices and catalysis.