Synergistic enhancement of triethylamine sensing performances via oxygen vacancy-rich Co-doped MnO2@MnCo2O4.5 nanorods/nanosheets

The presence of oxygen vacancies in p-type metal-oxide semiconductors significantly boosts gas-sensing performance. Despite this, the current literature lacks extensive studies on inducing oxygen vacancies in manganese-based oxides to enhance their intrinsic activities. Thus, developing a simple and efficient synthetic method to generate abundant oxygen vacancies in manganese-based oxides is essential. In this study, we achieved a straightforward transformation of Co-doped-MnO2 into MnCo2O4.5 nanosheets with plentiful oxygen vacancies by reducing then with NaBH4 solution at room temperature. This uncomplicated process effectively produced MnCo2O4.5 nanosheets with numerous oxygen vacancies, which markedly improved the gas-sensing properties. The hierarchical Co-doped-MnO2@MnCo2O4.5 nanorods/nanosheets nanocomposite, benefiting from the Co doping and reduction strategy, demonstrated superior gas-sensing performance compared to pristine MnO2 nanowires. Specifically, the sensor's response based on Co-doped-MnO2@MnCo2O4.5 to 50 ppm TEA gas increased by 340% at an optimal operating temperature of 170 degrees C, which is 2.7 times higher than that of pristine MnO2. This exceptional performance is attributed to the synergistic effect of oxygen vacancies and active sites within the hierarchical nanocomposite structure.