Fabrication and Enhanced Acetylene Sensing Properties of PdO-Decorated SnO_2 Composites Chemical Sensor

摘要

Pure and PdO-decorated SnO_2 nanospheres with different contents were synthesized with a facile and environment-friendly hydrothermal process. X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS) were used to characterize the crystalline composition and the morphology of the prepared materials, respectively. Planar-type chemical gas sensors were fabricated and their sensing properties to acetylene gas (C_2H_2), an important characteristic hydrocarbon contaminant dissolved in power transformer oil as a result of faults, were systemically investigated. Interestingly, C_2H_2 sensing properties could be obviously enhanced by adding PdO decoration. Among the four sensors, the 10 at% PdO-decorated SnO_2 sensor displays the most superior sensing characteristics, and its optimum operating temperature is measured to be about 360℃. Its highest response to 50 uL/L of C_2H_2 is measured to be about 12.32, which is 3.80 times larger than that of the pure SnO_2 sensor. The response time and recovery time of the 10 at% PdO-decorated SnO_2 to 50 uL/L of C_2H_2 are about 16 s and 22 s. Moreover, good long-term stability is also observed. All results lay a solid foundation for exploring high performance SnO_2 based chemical sensor to detect C_2H_2 gas extracted from power transformer oil.