Gadolinium-Doped CeO2 Gas Sensor for H2S Sensing

다국어 초록 (Multilingual Abstract)

Dihydrogen sulfide (H2S) gas has a flammable nature and is one of the most toxic and dangerousgases. Even small concentrations can be fatal to humans. Herein, we investigated the H2S gas-sensingfeatures of commercial pristine cerium oxide (CeO2) and gadolinium (Gd)-doped CeO2 (GDC) nanoparticles.
First, the sensing materials were well-characterized using various methods including X-ray photoelectronspectroscopy, transmission electron microscopy and X-ray diffraction to gain insight into their chemicalcomposition, morphology, phases, and crystallinity, respectively. In the next step, gas sensors were fabricatedusing a top electrode (Au/Ti) configuration. Preliminary H2S-gas-sensing studies revealed that GDC gas sensorhad a superior gas response to H2S gas than the pristine CeO2 gas sensor at 350°C. The responses of thepristine CeO2 gas sensor to 20 ppm H2S gas was 1.542, while the response of the GDC gas sensor to theaforementioned H2S concentration was 3.489. In addition, the GDC sensor exhibited good selectivity to H2Sgas among C2H5OH, C7H8 and NH3 gases. Also, we investigated the response of the sensor in up to 60%relative humidity. The enhanced response of the GDC gas sensor to H2S gas was mainly related to theformation of oxygen defects as a result of Gd-doping in CeO2. Also, good selectivity to H2S was related to thesensing temperature, the higher reactivity of H2S relative to other gases and the small bond energy of H-SH.
This study demonstrates the promising ability of Gd-doping to enhance the H2S gas-sensing characteristicsof CeO2, which can be applied to other similar systems based on semiconducting metal oxides.