Surface Selenium Coating Promotes Selective Methanol-to-Formate Electrooxidation on Ni3Se4 Nanoparticles

Abstract

In the quest to replace fossil fuels and reduce carbon dioxide emissions, developing energy technologies based on clean catalytic processes is fundamental. However, the cost-effectiveness of these technologies strongly relies on the availability of efficient catalysts made of abundant elements. Herein, this study presents a one-step hydrothermal method to obtain a series of Ni₃Se₄ nanoparticles with a layer of amorphous selenium on their surface. When employed as electrocatalysts for the methanol oxidation reaction (MOR), the optimized proper surface Se-coated Ni₃Se₄ nanoparticles exhibit a high current density of 160 mA cm^–2 at 1.6 V, achieving a high methanol-to-formate Faradaic efficiency above 97.8% and excellent stability with less than 20% current decay after an 18 h chronoamperometry test. This excellent performance is rationalized using density functional theory calculations, which unveil that the electrochemical recombination of SeO_x results in a reduction of the energy barrier for the dehydrogenation of methanol during the MOR process.