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

Improving the gas-sensing performances of p-type oxide semiconductors is an important research issue. Here, we reported the simple fabrication of bare Co 3 O 4 and Mn-doped Co 3 O 4 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 Co 3 O 4 . Besides, these prepared samples were used for detection of carbon monoxide (CO). Results show that 3 mol% Mn-doped Co 3 O 4 nanosheets present enhanced CO-sensing properties [(R g − R a )/R a = 280% to 40 ppm at 125 °C] compared with bare Co 3 O 4 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 Co 3+ /Co 2+ ratio. The Mn-doped Co 3 O 4 sensor has a huge potential advantage in detecting low concentrations of CO.