A thermodynamic approach toward selective and reversible sub-ppm HS sensing using ultra-small CuO nanorods impregnated with NbO nanoparticles

This paper provides an ideal solution to the challenges of employing CuO nanoparticles for the reversible, selective, and stable detection of sub-ppm H 2 S gas. This scheme presents a hidden thermodynamic advantage that makes both sulfidation and oxidation reactions reversible over a wide range of temperature (100-220 °C) by the addition of Nb 2 O 5 nanoparticles coupled with Gibbs free energy changes. Our optimized sensor composed of CuO-Nb 2 O 5 composites at 220 °C exhibits excellent selectivity toward H 2 S and SO 2 gases, ultralow detection concentration of 500 ppb, fast response time (