Revealing the effect of sulfur doping in NiCo-layered double hydroxides for enhanced electrocatalytic water splitting and glucose sensing performance

Abstract

Enhancing performances of electrocatalytic water splitting and electrochemical glucose sensing by varying the electronic structure is of great significance for hydrogen production and health management. In this work, a difunctional electrocatalyst sulfur doped nickel cobalt layered double hydroxide (S-doped NiCo-LDH) were prepared to investigate how the S doping affects the electronic structure and thereby the corresponding performance. The experimental characterization and theoretical calculation manifest that S doping can increase the valance state ratio of Co²⁺/Co³⁺ and the upshift of d band centers, accompanied with the reduce energy barriers of *H and *OOH formation for the initial step in (HER) and the determining step in (OER), and larger adsorption energy for glucose. In consequence, S-doped NiCo-LDH delivered low overpotentials of 183 mV and 246 mV at 10 mA cm⁻² for HER and OER along with excellent stability for glucose sensing. Furthermore, it also achieved an ultrahigh sensitivity of 2509.6 μA mM⁻¹cm⁻² in a linear range of 0.01–1.21 mM and displayed satisfactory selectivity, reproducibility and stability. This study presents an efficient approach to improving the performance of electrocatalysts for difunctional applications