Direct carbonization of cobalt-doped NH2-MIL-53(Fe) for electrocatalysis of oxygen evolution reaction

Abstract

In this work, we synthesized high-performance electrocatalysts for oxygen evolution reaction (OER) by one-step carbonization of cobalt(Co)-doped NH₂-MIL-53(Fe) with different molar ratios between Fe and Co. The results showed that the as-prepared composite with a molar ratio between Fe and Co = 1 : 3 and the calcination temperature of 550 °C displayed the best OER activity, denoted as MOF(Fe₁–Co₃)_550N. The MOF(Fe₁–Co₃)_550N possesses a microporous structure with a high Brunauer–Emmett–Teller (BET) surface area of 235.37 m²·g⁻¹. It shows excellent OER catalytic behavior in 0.1 M KOH solution. The overpotential at 10 mA cm⁻² is 0.39 V and the Tafel slope is 72.9 mV dec⁻¹, which is comparable to that of the as-synthesized RuO₂. The satisfactory results are attributed to the presence of pyridine N, Co₃O₄, the enlarged surface area and the micropore structures after calcination.