Fig. 5.

A UV–vis and photographs of (a) Ni-hemin MOF solution (b) Ni-hemin MOF +TMB + H₂O₂ (c) Ni-hemin MOF +TMB + H₂O₂ +H₂SO₄, B Time-dependent UV–vis spectral changes of TMB solution with H₂O₂ catalyzed by NiO MOF, C Time-dependent absorbance changes of (a) Ni-hemin MOF solution (b) TMB + H₂O₂ (c) Ni-hemin MOF +TMB + H₂O₂ at 652 nm, and D Time-dependent absorbance changes of TMB solution with H₂O₂ at 652 nm in the presence of different concentrations of NiO MOF