Surfactant-Assisted Electrodeposition of Manganese Carbonate for Efficient Hydrogen Evolution in an Acidic Medium

Developing cost-effective, eco-friendly electrocatalysts for the hydrogen evolution reaction (HER) is essential for sustainable hydrogen production. In view of this, MnCO3 is reported as an electrocatalyst for HER. However, the HER performance of MnCO3 is inferior to the benchmark catalyst, Pt/C and requires further improvement. This study significantly enhances the HER performance of MnCO3 via the electrochemical interfacial templating technique. MnCO3 is electrodeposited on pencil graphite at 2 V using three surfactants: cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and triton X-100 (TX-100) at different amounts. Uniform and stable deposits are obtained with 500 mg of surfactant. While structural analysis confirms successful deposition of MnCO3, microscopic studies reveal the surfactant-dependent textural properties of MnCO3. MnCO3 electrodeposited with 500 mg of SDS demonstrates outstanding HER performance (an overpotential of 51 mV at 10 mA cm-2 (10), comparable to Pt/C, 59 mV) and it outperforms Pt/C at higher current densities. In addition, a progressive improvement in the HER performance is observed on continuous operation (> 50 hours of chronoamperometry at 10 and 5000 cycles of linear sweep voltammogram), which indicates excellent long-term stability and durability.