Effect of Pd-Sensitization on Poisonous Chlorine Gas Detection Ability of TiO2: Green Synthesis and Low-Temperature Operation

Abstract

Ganoderma lucidum mushroom-mediated green synthesis of nanocrystalline titanium dioxide (TiO2) is explored via a low-temperature (≤70 °C) wet chemical method. The role of Ganoderma lucidum mushroom extract in the reaction is to release the ganoderic acid molecules that tend to bind to the Ti4+ metal ions to form a titanium-ganoderic acid intermediate complex for obtaining TiO2 nanocrystallites (NCs), which is quite novel, considering the recent advances in fabricated gas sensing materials. The X-ray powder diffraction, field emission scanning electron microscopy, Raman spectroscopy, and Brunauer–Emmett–Teller measurements etc., are used to characterize the crystal structure, surface morphology, and surface area of as-synthesized TiO2 and Pd-TiO2 sensors, respectively. The chlorine (Cl2) gas sensing properties are investigated from a lower range of 5 ppm to a higher range of 400 ppm. In addition to excellent response–recovery time, good selectivity, constant repeatability, as well as chemical stability, the gas sensor efficiency of the as-synthesized Pd-TiO2 NC sensor is better (136% response at 150 °C operating temperature) than the TiO2 NC sensor (57% at 250 °C operating temperature) measured at 100 ppm (Cl2) gas concentration, suggesting that the green synthesized Pd-TiO2 sensor demonstrates efficient Cl2 gas sensing properties at low operating temperatures over pristine ones.

Low-Temperature and High-Sensing Chlorine Sensor Based on Mesoporous SnO2 Wrinkled Nanosheets Inherited from Waste Cabbage Leaves

“…However, it is a highly corrosive, extremely toxic, and explosive gas, which can irritate eyes and damage the respiratory system once in contact and inhalation. In general, low concentration may cause bronchitis or asthma, and high concentration can cause asphyxiation or sudden death. , Accordingly, the occupational exposure limit (OEL) is set as 0.5 ppm . Thus, rapidly and accurately monitoring low concentrations of Cl 2 gas in the environment and production is essential.…”

“…In general, low concentration may cause bronchitis or asthma, and high concentration can cause asphyxiation or sudden death. 2,3 Accordingly, the occupational exposure limit (OEL) is set as 0.5 ppm. 4 Thus, rapidly and accurately monitoring low concentrations of Cl 2 gas in the environment and production is essential.…”