Manganese Carbonate (Mn₂(CO₃)₃) as an Efficient, Stable Heterogeneous Electrocatalyst for the Oxygen Evolution Reaction

With the growing population and energy demand, there is an urgent need for the production and storage of clean energy obtained from renewable resources. Water splitting electrocatalytically is a major approach to obtain clean H2. The efficiency, stability, and slow kinetics of anode materials developed so far do not fit the commercial application of the water oxidation reaction. To develop an efficient energy conversion catalyst, particularly for the oxygen evolution reaction (OER) herewith, Mn2(CO3)3 was electrodeposited on a Ni foam (NF) electrode surface by the chronoamperometric technique. The deposited Mn2(CO3)3/NF was characterized using various surface characterization techniques. The electrochemical behavior of the Mn2(CO3)3/NF-deposited electrode toward the OER was studied using electrochemical methods in KOH (pH 14) and NaHCO3 (pH 8.3) electrolytes. The Mn2(CO3)3/NF electrode showed a lower overpotential than CO3/NF and NF electrodes in the KOH/NaHCO3 media. The Mn2(CO3)3/NF electrode performs high electrocatalytic water oxidation with an overpotential of 360 mV at a current density of 10 mA·cm-2. This overpotential is much lower than those of CO3/NF (460 mV) and bare NF (520 mV), with good long-term stability in the KOH medium without any catalytic degradation after 100 CV cycles and 15 h chronoamperometric studies. The stability of the electrodeposited Mn2(CO3)3 on the NF electrode was determined by X-ray photoelectron spectroscopy. Thus, the Mn2(CO3)3/NF catalyst is suitable for the oxygen evolution reaction.