Three-dimensional commercial-sponge-derived Co3O4@C catalysts for effective treatments of organic contaminants

This study concerns an application of spongin-based scaffolds of commercial sponge origin as a naturally structured precursor of carbon material. Further functionalization with cobalt via a simple sorption-reduction method resulted in the preparation of novel catalysts tested in oxidation-reduction reactions. The structure and chemical composition of the prepared materials were investigated in detail, demonstrating the presence of carbonized fibers tightly covered with a metal-containing phase mainly composed of Co3O4. The fibrous structure with open porous canals provides good accessibility for substrates to the surface of the catalysts. Biocarbon material obtained at 600 °C exhibited good catalytic ability in the oxidation of styrene (with high selectivity for the formation of styrene oxide) and rhodamine B compared with other prepared catalysts and biocarbons. Interestingly, all of the prepared materials exhibit favorable activity in the reduction of 4-nitrophenol. A reusability study showed good activity even after the fifth catalytic cycle in both oxidation and reduction reactions. The study proved the adaptability of spongin-based scaffolds to prepare biocarbons with high potential to be used as a support for various catalytic applications.