Highly sensitive H2S gas sensors based on Pd-doped CuO nanoflowers with low operating temperature

Abstract A facile method was used to prepare Pd-doped CuO nanoflowers with various doping concentrations. The samples were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), inductively coupled plasma atomic emission spectrometer (ICP-AES), and Brunauer – Emmett – Teller (BET) specific surface area analysis. The responses (Rg/Ra or Ra/Rg, where Rg is the resistance in gas, and Ra is the resistance in air) of such sensors exposed to 50 ppm CH4, NO2, C2H5OH, H2S, NH3, and H2 were measured for comparison. For 1.25 wt% Pd-doped CuO nanoflowers, the response (Rg/Ra) to 50 ppm H2S was 123.4 at 80 °C, which was significantly higher than that of pure CuO (Rg/Ra = 15.7). Furthermore, excellent stability and repeatability of the gas sensor were also demonstrated. The observed results clearly revealed that it is an important and facile approach to detect the H2S at low operating temperature for practical applications.