Sn and Mn co-doping synergistically promotes the sensing properties of Co3O4 sensor for high-sensitive CO detection

In the realm of gas sensors, p-type metal oxide semiconductor (MOS) usually exhibits inherently low sensitivity toward target gases caused by the hole accumulation layer configuration , which seriously hinders its practical application. Diatomics co-doping is an efficient tactic for adjusting the characteristics of MOS related to gas-sensing due to their synergistic effect . In this work, we controllably synthesized bare Co 3 O 4 , Sn-doped Co 3 O 4 , Mn-doped Co 3 O 4 and Sn/Mn co-doped Co 3 O 4 nanosheets . The experimental results reveal that Sn/Mn co-doped Co 3 O 4 sample presents porous nanosheets structure. 1 mol% Sn/Mn co-doped Co 3 O 4 sensor presents enhanced response [(R g -R a )/R a = 330 %∼40 ppm at 150 °C] toward CO compared with the bare Co 3 O 4 , 1 mol% Sn-doped Co 3 O 4 , and 1 mol% Mn-doped Co 3 O 4 nanosheets. Besides, 1 mol% Sn/Mn co-doped Co 3 O 4 nanosheets show a low limit of detection (500 ppb/experimental value), good stability and selectivity. We infer that the good CO-sensing properties may be ascribed to the oxygen vacancies defects generated by Sn 4+ and Mn 2+ /Mn 3+ co-doping, high Co 3+ ratio, and high specific surface area. This study affords an effective co-doping strategy for enhancing the gas-sensing performances of p-type MOS.