NiCo PBA-derived Co/P dual-doped Nickel Sulfide on Nickel Foam as an efficient electrocatalyst for water splitting

초록

Water electrolysis is a promising method for high-purity hydrogen production, but its efficiency is limited by the sluggish kinetics of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). While noble metal-based catalysts such as RuO2 and Pt/C exhibit excellent performance for OER and HER, their high cost and scarcity hinder practical applications. To address these challenges, transition metal-based compounds have garnered significant attention due to their affordability, abundance, and high catalytic activity. Among these, transition metal sulfides (TMSs) stand out for their high electrical conductivity and unique electronic properties, which are attributed to the electronegativity of sulfur. Moreover, Prussian blue analogues (PBAs), known for their tunable compositions, open frameworks, and high specific surface areas, have been extensively applied in the energy storage and conversion fields. Particularly, their derivatives, such as TMSs, exhibit superior electrocatalytic properties and homogeneous metal distributions. Additionally, dual doping strategies have been employed to tailor the electron density of PBA-derived TMSs, creating favorable active sites and improving reaction kinetics. These advancements position PBA-derived TMSs as promising candidates for cost-effective and efficient water electrolysis systems. Inspired by these considerations, we designed a strategy to directly grow Ni3S2 with Co and P dual-doped structures on nickel foam (NF) via a hydrothermal reaction and subsequent pyrolysis. Initially, nickel hydroxide (Ni(OH)2) was prepared using hydrothermal methods to increase the surface area for further composition. Next, a nickel-cobalt bimetallic PBA was synthesized under low pH conditions, promoting Ni2+ leaching from the nickel hydroxide. According to Le Chatelier's principle, the acidic environment shifts the equilibrium, favoring the dissolution of nickel ions. The obtained NiCo PBA/NF was then subjected