FeS-decorated nickel iron hydroxide with a regulated coordination environment towards improved methanol oxidation reaction

Abstract

Methanol oxidation reaction (MOR) has garnered extensive attention as a pivotal technology for the synthesis of high-value-added products. However, the high selectivity of methanol oxidation products into high-value formic acid requires precise control of the reaction pathway and the reconstruction of Ni. Herein, a microbial corrosion strategy was employed to construct Ni(Fe)(OH)₂–FeS nanosheets. The constructed Ni(Fe)(OH)₂–FeS electrode exhibits superior MOR performance, achieving 1.378 V vs. RHE at 10 mA cm⁻² with a Tafel slope of 21 mV dec⁻¹. Density functional theory calculations indicate that the introduced S²⁻ enables modulation of the d-band center and the coordination environment of Ni sites. Furthermore, this effect can promote the buildup of *OH at the active site, thus increasing the local *OH concentration around the electrode surface. Moreover, the anion S²⁻ promotes the surface reconstruction of Ni(Fe)(OH)₂ and enhances the Ni–O bond in Ni(Fe)OOH–FeS, thereby optimizing the adsorption and binding energy of the intermediate, which significantly enhances the MOR performance. This innovative design facilitates the controlled conversion of the *CHO intermediate to HCOOH by enhancing the CO-free pathway, demonstrating significant potential in fostering the sustainable advancement of the interdisciplinary fusion between biology and clean energy technologies.