Excellent low-temperature catalytic performance of nanosheet Co-Mn oxides for total benzene oxidation

Abstract

A series of CoaMnbOx oxides (a/b = 1:1∼7:1) at 500 °C and Co2Mn1Ox at a temperature range of 300–700 °C were prepared by an oxalate co-precipitation method and evaluated of catalytic performance for benzene total oxidation. It is found that Co2Mn1Ox catalyst displays the best activity among all the CoaMnbOx oxides. The typical uniform nanosheet morphology plays a vital role in achieving the relatively high activity of Co2Mn1Ox. A detailed characterization has illustrated that the calcination temperature is also an important factor to influence the structure, physico-chemical properties and thus catalytic performance of Co2Mn1Ox. Co2Mn1Ox calcinated at 300 °C (CM300) presents pretty thin nanosheet and small particle size of 6.6 nm. It displays a better low-temperature catalytic activity than those obtained at temperatures of >300 °C: under the conditions of 20,000 mL g−1 h−1 and 1500 ppm of benzene, the temperature at 90% conversion of benzene oxidation is 191 °C, which is lower than that of some related reports in the literatures. Furthermore, CM300 performed excellent long-term stability. It is concluded that the superior catalytic performance of CM300 is associated with its relatively large specific surface area, good low-temperature redox property, abundant active oxygen species and active components (Co2+ and Mn4+). Co-Mn oxides will be the potential alternative of precious metals for the removal of volatile organic compounds in the industrial field.