Fig. 11

Photocatalytic activity of pure Co₃O₄ and the different fabricated p-Co₃O₄/n-ZnO heterostructures: a the relative concentration of MO as a function of irradiation time ((C₀ and C are the concentration of MO at initial and any time)), b the degradation efficiency of MO in 72 h, c first-order plot of MO