Self-Assembled Manganese Sulfide Nanostructures on Graphene as Oxygen Reduction Catalyst for Anion E

ChemElectroChem 2017, 4, 1–11.

Development of active, inexpensive and durable non-precious metal electrocatalysts to replace high cost Pt-based catalysts towards commercialization of fuel cell technology is the focus in recent days. In this regard, we report a facile one pot hydrothermal synthesis of self-assembled manganese sulfide on graphene layers (MnS/G) and recognised as non-precious metal catalyst for an efficient oxygen reduction reaction (ORR) in alkaline medium. The phase purity and surface morphologies are investigated using X-ray diffraction and scanning electron microscopic techniques, respectively. The optimised MnS/G with 50% Mn exhibited excellent ORR property with onset and half-wave potentials of 0.83 and 0.71 V vs RHE, respectively. While evaluating the durability, only 90 mV negative shift in its half-wave potential is observed after 5,000 repeated potential cycling and is also ascertained up to 48 h of operation at a constant potential using chronoamperometric technique with 28% degradation in the current. The optimised material is utilised as cathode catalyst while fabricating membrane electrode assembly to validate in anion exchange membrane fuel cell (AEMFC). A peak power density of 12 mW cm-2 was realized in H2-O2 feeds under ambient temperature and pressure; thus looks as an alternative non-precious metal catalyst for fuel cell applications.