Enhanced performance of carbon-coated manganese catalysts derived from metal-organic framework for rechargeable zinc-air batteries

The wide structural versatility of the Metal-Organic Framework (MOF) is considered to be potential catalysts. In this work, [Mn (BDC)center dot nDMF](n) was synthesized by the reaction of 1,4-benzene dicarboxylic acid (1,4-BDC) with Manganese (II) nitrate using a solvothermal method. The [Mn(BDC)center dot nDMF](n )crystals were calcined for 2 h to produce Mn-MOF derived catalysts (C@MnO catalysts). The formation of MnO crystals was investigated by the X-ray diffraction (XRD) and the Raman Spectroscopy analyzed the graphitization. The resulting catalysts, C@MnO are highly porous with a high specific surface area of 291.62 m(2) /g at 700 degrees C. After calcination, Ni deposition was performed, to produce Ni@C@MnO on which Ni-atoms are deposited on the surface of MnO. The surface area reduces to 214.09 m(2)/g at 700 degrees C and the structure is distorted due to deposition. Numerous characterization techniques, including XRD, SEM, EDS, TGA, and Raman, strongly support the effective incorporation of Mn and Ni into the material frameworks. When applied as a cathode for Zinc-air battery, the Ni@C@MnO electrode delivered a high current density of 0.206 Acm(-2) for the OER. The cyclic test for charging-discharging was performed for 152 cycles revealing a potential catalyst, having splendid stability for the OER and ORR.