Catalytic manipulation of Ni nanostructures-immobilized CNTs via nitrogen coupling for robust water electrolysis and effective glucose detection

The development of a novel multifunctional high-performance electrocatalyst is a critical requirement for electrochemical applications. This study reports an effective engineering approach to enhance multi-integrated active sites of nickel (Ni) catalysts through the coupling of nitrogen (N) atoms to trigger surface-functionalized Ni nanoparticles that are well dispersed over a structure of carbon nanotubes (CNTs). Excitingly, the N-doped Ni@CNTs material possesses good catalytic features with a required overpotential (η) of ∼133.8 mV to achieve 50 mA/cm² toward hydrogen evolution reaction and ∼330 mV to achieve 100 mA/cm² toward oxygen evolution reaction in 1.0 M KOH. To assess overall water splitting practicability, an electrolyzer device derived from the N-doped Ni@CNTs_(+,−) is fabricated and shows an operation voltage of only ∼1.62 V at 10 mA/cm² together with a prospective stability that is superior to Pt/C₍₋₎//RuO₂₍₊₎. Furthermore, the non-enzymatic glucose sensor derived from the N-doped Ni@CNTs electrode displays high sensitivity of 5.2 μA/mM/cm², wide linear range of (0.01–3.7) mM, low detection limit of ∼17.4 μM (S/N = 3), excellent selectivity, and long-term stability. Our study suggests that the developed N-doped Ni@CNTs are favorable catalyst for practical water electrolysis to produce green hydrogen and for non-enzymatic glucose sensor application.