Novel monolithic catalysts derived from in-situ decoration of Co3O4 and hierarchical Co3O4@MnOx on Ni foam for VOC oxidation

Monolithic Co3O4 and Co3O4@MnOx catalysts have been successfully prepared by in-situ growth. The morphology control and formation mechanism of Co3O4 on Ni foam was investigated in detail. Among the different samples, bamboo leaf-like Co3O4-NF-10 presented good catalytic activity for acetone oxidation (T-50 = 179 degrees C, T-90 = 193 degrees C), which was attributed to its low temperature reducibility, abundant Co3+ and surface adsorbed oxygen species (O-ads). Therefore, Co3O4@MnOx-NF was further prepared to obtain abundant Co3+ and O-ads species due to the redox reaction between MnO4- and Co2+. As expected, the Co3O4@MnOx-NF catalyst presented significantly improved activity for not only acetone but ethyl acetate and toluene oxidation compared to the Co3O4-NF-10. The high catalytic performance of Co3O4@MnOx-NF was ascribed to its good low-temperature reducibility, abundant Co3+ and O-ads species. In addition, Co3O4@MnOx-NF presented a satisfactory cycle and long-term stability. This work shed light on the design of monolithic catalysts in VOC oxidation.