Ppb H2S gas sensing characteristics of Cu2O/CuO sub-microspheres at low-temperature

Cu2O/CuO sub-microspheres were synthesized via a one-step reduction approach using copper (II) acetate as precursor in triethylene glycol solution at reaction temperature ranging from 100 to 180 °C. It is found that the reaction temperature plays a very important role in the size, the Cu2O content, and morphology of the products. The sub-microspheres obtained at the reaction temperature below 140 °C are assembled by smaller particles with a diameter of about 10 nm. As the reaction temperature is increased to above 160 °C, uneven samples with larger size will be synthesized. The sensing performances of the sub-microspheres are related to the Cu2O content, porous characteristics and their surface areas. The sensor response of the sub-microspheres obtained at 120 °C is up to 2.1–50 ppb H2S gas at 95 °C, and the recovery time is only about 76 s. Thus, the sub-microspheres are promising for H2S sensors.