Incorporation of MnO 2 nanoparticles into MOF-5 for efficient oxygen evolution reaction

A composite MnO 2 @MOF-5 is prepared by in situ incorporation of pre-synthesized MnO 2 nanoparticles into metal organic framework, MOF-5, during synthesis. The product is characterized by powder X-ray diffraction analysis, Raman spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and elemental mapping, which support the formation of proposed composite materials. The oxygen evolution reaction activity of MnO 2 @MOF-5 composite is evaluated by cyclic voltammetry, linear sweep voltammetry, and chronoamperometric measurement under visible light. It is found that MnO 2 @MOF-5/NF has better durability and ability to produce a current density of 10 mAcm −2 at only 324 mV overpotential with lower 71 mVdec −1 Tafel slope as compared to some of previously reported Mn-based catalysts for oxygen evolution reaction (OER). The stability of these electrodes is evaluated by chronoamperometric studies for 6000 s in the presence of visible light, and they showed constant current density. Furthermore, the stability studied by continuous CV sweeps in 1.0 M NaOH at a scan rate of 100 mVs −1 shows that these materials are stable up to 100 cycles, which confirms the stability and durability of the electrodes. Graphical abstract