Synthesis of MOF doped Cu for water spilliting in alkaline media

The development of renewable energy sources has recently drawn an increasing amount ofattention as a means of addressing the global problems of environmental pollution and rising energyconsumption[۱]. Among the many options, hydrogen energy shows itself to be a strong contenderas a clean and carbon-neutral energy source. Widely accepted as the best approaches to thehydrogen evolution reaction (HER), where electrical energy is used to directly split water, are electrochemical and photoelectrochemical water splitting[۲]. The oxygen evolution reaction (OER), which involves a sequential proton-coupled electron transfer step and is more complex thanthe straightforward two-electron transfer process for HER, has relatively low kinetic rates and continues to be a significant barrier to the advancement of water splitting applications[۳]. It isurgently necessary to create highly active electrocatalysts in order to reduce overpotentials andspeed up reaction rates[۴].In this study, three metallic CoNiCu are successfully synthesized via the thermal annealing by doping Cu to MOF based NiCo as reported by Lin et al [۵].All electrochemical performances were evaluated by using an electrochemistry workstation (VSP-۳۰۰) on a standard three-electrode system in ۱.۰ M KOH electrolyte with glassy carbon electrode (GCE, ۳ mm) coated with catalyst as the working electrode, a platin electrode as the counter electrode, and Ag/AgCl electrode and the reference electrode. To form homogeneous ink, ۲ mg of catalyst was dissolved in a mixed solution containing water-ethanol (۴:۱, v/v) and Nafion solution (۴۰ L, ۵ wt%) and sonicated for ۳۰ minutes. The working electrode was then created by dropping۵ μL of ink onto the GCE (۰.۱۳۶ mg cm۲). Linear sweep voltammetry (LSV) measurements were conducted at ۵ mV s-۱.The catalysts exhibits ۹۶ mV overpotential (η) at a current density of ۱۰ mA cm−۲ , for OER. Theobtained catalyst shows an onset potential of ۱.۵۵ V vs. RHE and ۲۸۰ mA cm−۲ current density at ۱.۹V vs RHE in the presence of ۱ M KOH. The observed results of OER catalytic behavior are better than noble benchmark Pt/C catalyst under identical conditions. The results suggested that the MOF plays a major role in enhancing the catalytic activity, stability and electronic properties due to their porous and interconnected structure.

کلیدواژه ها:

CoNiCu ، MOF ، water spiliting ، oxygen evolution