Multiwalled Carbon Nanotubes and CuO Nanoparticles Composite based H₂S Sensors

H₂S is an extremely hazardous air pollutant that harms the human respiratory system and world ecosystems. The main sources of H₂S emissions are sewage, petroleum industries, and natural gas. The demand for some sensing mechanism to monitor its emissions is paramount. Herein, we demonstrate CuO nanoparticles and multiwalled carbon nanotubes (MWCNTs)-based H₂S sensors. The conventional chemical vapor deposition technique (CVD) is used for growing MWCNTs. The optimal amount of MWCNTs and CuO nanoparticles in the composite enhanced the H₂S sensor response. The experimental data confirmed that the bare CuO sensor response (ΔR/R%) for 1 ppm H₂S was 31%; further MWCNTs/CuO heterojunction sensor responses reached 53%. The enhanced sensing characteristics are a result of the formation of nano-heterojunctions between MWCNTs and CuO nanoparticles, which enhance the chemical and electronic sensitization properties. In addition, the heterojunction sensor demonstrated excellent H₂S selectivity over other oxidizing and reducing gases.