Fabrication of Macroporous Co₃O₄–MgO Composite Catalysts for Methylene Blue Degradation Using Oxone as an Oxidant

Abstract

Macroporous Co₃O₄–MgO composites with uniform pores of 0.3–1.0 µm were successfully fabricated for the first time by the sol–gel method using poly(methyl methacrylate) (PMMA) particles as a template. The macropore size and BET surface area were easily controlled by selecting a proper size of the commercial PMMA microspheres. In addition, the composites showed smaller Co₃O₄ particles than the catalysts prepared by the conventional impregnation method. High surface area composite catalysts with controlled porous structure exhibited a higher methylene blue degradation activity in the presence of Oxone as an oxidant than conventional supported catalysts. Because good dispersion of the active Co₃O₄ species is a key factor to enhance the catalytic activity, this finding could be attributed to the good mixing of Mg and Co precursors, a distinct advantage of the sol–gel technique.