Synthesis and enhanced H2S gas sensing properties of α-MoO3/CuO p–n junction nanocomposite

One-dimensional (1D) α-MoO3/CuO nanocomposite has been synthesized via a simple method. This nanocomposite consists of n-type α-MoO3 nanorods decorated with p-type CuO nanoparticles, leading to the formation of p–n junctions at their interfaces. The p–n junction nanocomposite exhibits great enhanced H2S gas sensing properties, compared to pristine α-MoO3 nanorods. The sensor response of this nanocomposite is up to 272.0–10 ppm H2S gas at the optimal working temperature (270 °C), which is 53.3 times higher than that of α-MoO3 nanorods. More importantly, even at 100 °C, α-MoO3/CuO p–n junction nanocomposite still has very strong response to 5 ppm H2S gas. In addition, the nanocomposite sensors have a very good selectivity to H2S gas. Such enhanced H2S sensing performances are attributed to the disappearance of p–n junctions, which can be proved by the fact that crystalline CuO nanoparticles are converted into amorphous CuS ones after the nanocomposite is exposed to H2S gas.