Efficient Catalytic Behavior by Cobalt and Manganese Oxides Species Supported on a 3DOM Carbon

Abstract

A series of heterogeneous catalysts was synthesized, characterized, and evaluated for the total oxidation of toluene, a representative volatile organic compound (VOC). Metal oxides (Mnx Oy , Co3 O4 , and Co3 O4 –Mnx Oy ) were deposited onto three-dimensionally ordered mesoporous (3DOM) carbon. The support exhibited a high surface area (325 m2 g− 1 ) and uniform mesoporosity ( ≈ 3.7 nm), enabling effective dispersion of the active phases. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the preservation of the ordered structure after impregnation, whereas x-ray photoelectron spectroscopy (XPS) revealed multiple oxidation states of cobalt (Co2 + /Co3 + ) and manganese (Mn2 + /Mn3 + /Mn4 + ), favoring redox cycling and oxygen mobility. Catalytic tests demonstrated that the bimetallic oxide system achieved complete toluene conversion (1000 ppm) with the highest activity (1.35 mol of TOL(Toluene) g− 1 s− 1 ), outperforming single-metal catalysts (Co3 O4 /3DOM: 0.84 mol of TOL g− 1 s− 1 ; Mnx Oy /3DOM: 1.22 mol of TOL g− 1 s− 1 ).