Manganese oxide nanoparticle carbon microparticle electrocatalyst and method of making from Albizia procera leaf

An electrocatalyst, consisting of:

• manganese oxide nanoparticles supported on carbon microparticles, the carbon microparticles having a flat platelet morphology with a thickness of less than 10 μm;
• and
• optionally, at least one binder selected from the group consisting of a conductive polymer, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, styrene butadiene rubber, a tetrafluoroethylene hexafluoroethylene copolymer, a tetrafluoroethylene hexafluoropropylene copolymer, a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene resin, a propylene-tetrafluoroethylene copolymer, and an ethylene-chlorotrifluoroethylene copolymer,
• wherein the manganese oxide nanoparticles are in the form of crystallites having an average diameter in a range of from greater than 10 to 25 nm, and the carbon microparticles are derived from Albizia procera leaves and have an average longest dimension in the range of from 100 to 300 μm,
• wherein the manganese oxide nanoparticles comprise hausmannite, tetragonal Mn3O4 and optionally further cubic MnO, and
• wherein the electrocatalyst has an Mn:C atomic ratio in a range of from 5:1 to 1:1.