Synthesis and characterizations of highly responsive H2S sensor using p-type Co3O4 nanoparticles/nanorods mixed nanostructures

High-quality p-type semiconducting Co 3 O 4 with mixed morphology of nanoparticles/nanorods are synthesized using a hydrothermal route for high response and selective hydrogen sulphide (H 2 S) sensor application. XRD and Raman studies revealed the crystal structure and molecular bonding for obtained Co 3 O 4, respectively. The nanoparticles/nanorods-like structures were confirmed for Co 3 O 4 using FESEM and TEM analysis. The EDS and XPS spectra analysis were carried out for elemental composition and chemical atomic states of Co 3 O 4 . The Co 3 O 4 sensor is investigated for gas sensing properties in dynamic conditions. The sensor exhibited the highest selectivity towards H 2 S among various hydrogen-contained gases at 225 °C. The sensor revealed a high response of 357% and 44% for 100 and 10 ppm H 2 S gas concentrations, respectively. The Co 3 O 4 sensor exhibited a systematic dynamic resistance response for 100–10 ppm range H 2 S gas. The excellent dynamic resistance repeatability of the sensor was shown towards 25 ppm H 2 S gas. The response of Co 3 O 4 sensor was investigated at different operating temperatures and H 2 S concentrations. The sensor stability and H 2 S sensing mechanism for the Co 3 O 4 sensor have been reported. Highly uniform and mixed nanostructures of Co 3 O 4 can be the potential sensor material for real-time high-performance H 2 S sensor application. • High quality Co 3 O 4 nanostructures preparation via hydrothermal route. • Co 3 O 4 sensor exhibits high selectivity towards H 2 S gas at 225 °C. • Co 3 O 4 sensor works in H 2 S gas concentration 10 ppm–100 ppm at 225 °C. • High response of 357% for 100 ppm H 2 S gas at 225 °C. • Co 3 O 4 sensor shows continuous transient response for concentration 100 to 10 ppm.