Selective H₂S sensor based on CuO nanoparticles embedded in organic membranes

We report on H₂S gas sensors based on CuO nanoparticles that are embedded within polymer membranes of poly-vinyl-alcohol (PVA) and glycerol ionic liquid (IL). The nanoparticles were fabricated by the colloid microwave assisted hydrothermal method that enables a precise control of nanoparticle size. Polymer solutions of PVA and 5% IL were prepared with different concentrations of nanoparticles. Next, the solutions were used to fabricate polymer membranes by the solution casting method. The produced membranes were flexible and they hold semiconducting properties. Each membrane was encapsulated between two electrical electrodes where the top and bottom electrodes were made of stainless steel grid and copper sheet, respectively. A constant voltage was applied across the electrodes, and the electrical current response signal was measured. The measurements revealed that those sensors were sensitive to H₂S gas with concentrations as low as 10 ppm, and they functioned at low temperatures. In addition, their sensing behavior was reversible which enabled repeatable use of those sensors. Those sensors were also selective to H₂S, and they exhibited fast response of 20.4 ± 12.8 s. Moreover, the sensors were easy to manufacture, thus, they have potential to be used for practical field applications.