Metal-organic frameworks-derived Mn-doped Co3O4 porous nanosheets and enhanced CO sensing performance

Abstract

Improving the gas-sensing performances of p-type oxide semiconductors is an important research issue. Here, we reported the simple fabrication of bare Co3O4 and Mn-doped Co3O4 porous nanosheets by annealing the Co-based metal-organic frameworks (MOFs) nanosheets precursors synthesized from the ion-assisted solvothermal treatment. Different characterization techniques were adopted to verify the physical and chemical morphologies of the as-prepared samples. The results demonstrate that Mn cations have been successfully doped into the lattice of Co3O4. Besides, these prepared samples were used for detection of carbon monoxide (CO). Results show that 3 mol% Mn-doped Co3O4 nanosheets present enhanced CO-sensing properties [(Rg − Ra)/Ra = 280% to 40 ppm at 125 °C] compared with bare Co3O4 nanosheets. The response reported here for the detection of CO even exceeds those of some n-type oxides under the same conditions. We speculate that the enhanced CO-sensing properties are probably due to the high specific surface area, abundant oxygen vacancies generated by Mn doping, and the relatively high Co3+/Co2+ ratio. The Mn-doped Co3O4 sensor has a huge potential advantage in detecting low concentrations of CO.