Co–Mn Bimetallic Metal–Organic Frameworks Nanosheets for Efficient Oxygen Evolution Electrocatalysis

Abstract

Developing an efficient oxygen evolution reaction (OER) catalyst is the footstone of many electrochemical energy conversion devices. Herein, a cobalt–manganese bimetallic metal–organic framework (MOF) is developed as an efficient OER catalyst (denoted as Co₃Mn₁ BDC). The Co₃Mn₁ BDC nanosheets demonstrate advantages in specific surface area, pore size distribution comparing with monometallic Co BDC and Mn BDC. The performance investigations demonstrate that the doping of Mn in Co-based MOFs facilitates the electrochemical area, charge transfer efficiency, reaction kinetics, and turnover frequency. As a consequence, the Co₃Mn₁ BDC exhibits a low overpotential of 289 mV at current of 10 mA cm⁻² and a favorable Tafel slope of 56.8 mV dec⁻¹ on glassy carbon electrode, which is better than IrO₂. When the catalyst is loaded on Ni foam, the overpotential and Tafel slope are further decreased to 231 mV and 50.8 mV dec⁻¹. Moreover, the Raman spectrum confirms that the Co₃Mn₁ BDC can be transformed into active CoOOH, suggesting the bright prospect in electrocatalysis devices as “precatalyst”.