Study on electrocatalytic oxygen evolution of nitrogen carbon materials derived from tungsten-doped NiFe MOFs

The oxygen evolution reaction in the two-step reaction of water electrolysis to hydrogen production involves complicated electron transfer steps. Designing an efficient oxygen evolution catalyst for hydrogen production by water electrolysis is essential. Based on the diverse catalytic activities of polyoxometalate (POM) and metal-organic frameworks (MOFs), this paper proposed to use Keggin-type polyoxometalate (K₆NaNi₃(H₂O)₃PW₁₀O₃₉H₂O) as tungsten source and combined it with MOFs. After nitrogen doping and calcination, tungsten-doped nitrogen-carbon materials are grown on nickel foam. SEM, XRD and XPS characterizations showed that the doped material was a tungsten-doped polyoxometalate and nickel-ferroalloy bimetallic nitro-carbon material with bead chain and Raman spectra showed that such material had a high number of defect structures that promote catalytic effect. The electrocatalytic oxygen evolution (OER) performance was studied using linear sweep voltammetry (LSV) and the Tafel curve. The results showed that in 1.0 mol/L KOH alkaline electrolyte, the material’s overpotential was 226 mV when the current density was 50 mA/cm². The Tafel slope was only 78.64 mV/dec, and the performance was almost unchanged after 10 hours of operation, showing good catalytic activity and stability.