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”.