Nickel–Copper Alloy Nanoparticles Embedded in N-Doped Porous Carbon Nanosheets for Supercapacitors and Hydrogen Evolution Reaction

Exploring high-performance and cost-affordable electroactive materials for hydrogen evolution reaction (HER) and energy storage is of paramount importance to respond positively to the looming energy crisis. Here we report a nitrogen-doped hierarchical porous carbon nanosheet decorated with nickel–copper alloy nanoparticles (NiCu@NHPC), which can be fabricated in large quantities using lactose and nitrate as precursors via a simple two-step carbonization strategy. No external template or pore-forming agent was used in the preparation process. The structural characterizations reveal that monodisperse NiCu alloy nanoparticles are tightly embedded into the porous carbon framework. Benefiting from its outstanding structure feature, the NiCu@NHPC hybrid exhibits exceptional electrochemical performance. Specifically, the NiCu@NHPC hybrid as supercapacitor electrode material displays a high specific capacity up to 1175 C g–1 at 1 A g–1 and a good rate performance. Meanwhile, the assembled asymmetric supercapacitor device NiCu@NHPC//NHPC delivers a desirable energy density of 61.33 Wh kg–1 at a power density of 960 W kg–1 and a long-term cycle life. More importantly, the NiCu@NHPC hybrid also manifests a superior electrocatalytic activity for HER with an overpotential of 80 mV at 10 mA cm–2, a lower Tafel slope (76 mV dec–1), and good durability in acidic media. This work provides a facile but effective strategy for designing bimetallic alloy@carbon hybrids for application as high-performance supercapacitor electrode material and HER electrocatalyst.