Ni–O–C/LNSP Core–Shell Heterostructure Mimicking Noble Metal-like Activity and Nonenzymatic Electrochemical Lactate Regulation in Human Sweat

Abstract

Herein, a core/shell LNSP (lamellar nanosheet–nanoplate) of nickel oxy carbide (Ni–O–C/LNSP) has been synthesized by a solvent-devoid combustion process, which exhibits exceptional oxygen evolution efficiency (OER) performance with an overpotential of 311 mV, a Tafel slope of 116 mV dec^–1, and stability over 8 h with 2.8% potential loss owing to more exposed active sites and high conductivity with the interface effect. The activation energy of 28 kJ/mol was calculated for electrolysis using Ni–O–C/LNSP. The calculated integrated area of 3.70 × 10^–5 AV (Ni–O–C/LNSP) established MOOH* formation with active sites of 4.619 × 10^–16. The ultrastability of Ni–O–C/LNSP for commercial application was shown by durability at 10/100 mA cm^–2 for the OER (GC─8 h, 2.8%; NF─100 h, 3.4/4.9%), UOR (60 h, 3.4%), SWO (60 h, 4.1%), MSWO (60 h, 5.6%), and overall water splitting (100 h, 3.9%). The effect of pH with the addition of tetramethylammonium cations (TMA⁺) reveals Ni–O–C/LNSP follows the lattice oxygen mechanism. The solar-driven water electrolysis at 1.58 V shows the effectiveness of Ni–O–C/LNSP for STH conversion. The multiple applications projected Ni–O–C/LNSP as an auspicious catalyst for energy applications. Using Ni–O–C/LNSP, we have generated H₂ effectively with a lower power consumption of 771.08 L_H2 kW h^–1 than bare NiO (801 L_H2 kW h^–1). The as-prepared Ni–O–C/LNSP used for nonenzymatic lactate detection showed a sensitivity of 71.05 μA mM^–1 cm^–2 at 1.54 V with [lactate] difference in human sweat corroborated under both anaerobic and aerobic exercise conditions using Ni–O–C/LNSP.