Solvent-free selective oxidation of ethylbenzene with molecular oxygen catalyzed by cobalt catalysts supported on exfoliated carbon nitride

Exfoliated graphitic carbon nitride (eg-C3N4) material was applied as a support to load cobalt catalysts (CoOx/eg-C3N4) through a simple impregnation method. The physical and chemical properties of the synthesized CoOx/eg-C3N4 materials were characterized by a series of analytic techniques including XRD, SEM, FT-IR, UV-vis, and XPS. The characterization results revealed that the introduction of Co2+ species had not altered the graphitic structure of eg-C3N4. The Co2+ species probably coordinatively interact with the nitrogen-containing group of eg-C3N4. The catalytic performances of the CoOx/eg-C3N4 were evaluated in the solvent-free selective oxidation of ethylbenzene (EB) using molecular oxygen as an oxidant. Among the 3CoO(x)/eg-C3N4 materials with various preparation temperatures, 3CoO(x)/eg-C3N4-400 exhibited the highest EB conversion, which was owing to its superior percentages of Co2+ and tertiary nitrogen species.