Improvement of NO2 Sensing Properties in Pd Functionalized Reduced Graphene Oxides by Electron-Beam Irradiation

Abstract

Herein, we present the effect of electron-beam irradiation (EBI) on the gas-sensing properties of Pd-functionalized reduced graphene oxide (RGO). Scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy were used to characterize the synthesized products. The samples were irradiated using electron beams at doses of 0 (Pd-RGO-0), 100 (Pd-RGO-100), and 500 kGy (Pd-RGO-500), and the NO2 gas-sensing properties were investigated. It was found that irradiation by electron beams has a critical effect on the gas-sensing properties of the samples, and the Pd-RGO-500 sensor showed the highest response to NO 2 gas. In particular, the response of the unirradiated sensor and the sensor irradiated at doses of 100 and 500 kGy to 10 ppm NO 2 were 1.027, 1.045, and 1.047, respectively. The response times of Pd-RGO-0, Pd-RGO-100, and Pd-RGO-500 to 10 ppm NO 2 gas were 389, 335, and 345 s, respectively. The corresponding recovery times for these sensors were 808, 766, and 816 s, respectively. The increased numbers of oxygen functional groups and high-energy defects were the main reasons for the increased gas response. This study will eventually lead to increased performance levels of RGO-based sensors that use EBI, as this technology can introduce changes into materials in a non-contact, clean, and powerful manner.

Ammonia Gas Sensing Behavior of Hybridization between Reduced Graphene Oxide and Gold Nanoparticles

“…The mechanism of increasing resistance in the presence of NH 3 gas is explained as follows: rGO and hybridized AuNPs with rGO sensing layers have p-type characteristics wherein holes act as the majority carriers. The electron donor effect of NH 3 gas molecules (reducing agent) will deplete the hole concentration in sensing layers upon adsorption which leads to an increase in resistance of sensor devices [1,4,6,10], [19,20]. Our results are comparable to the report of Sivalingam and Balasubramanian who used rGO/Au hybrid nanostructure for detecting 10,000 ppm of NH 3 gas at RT with the highest sensitivity of 10% [5].…”

“…Meanwhile, Sivalingam and Balasubramanian use the coreduction method of these precursors (at 80°C for 5 minutes) to synthesize rGO/Au film which was applied to NH 3 sensing at RT [4,5]. Choi et al synthesize rGO and then deposit the Pd layer on the rGO surface by a sputtering process and thermal annealing; a NO 2 gas sensor at RT was made from this Pd-rGO hybrid [6]. From these reports, it can be seen that the mechanism and performance of the sensor depend strongly on the metal used and the synthesis method.…”

Electron Beam Induced Tailoring of Electrical Characteristics of Organic Semiconductor Films

“…2 MeV EB provokes oxygen functional group adsorption and non oxygen defects in reduced grapheneoxide which is mainly responsible for improved responsivity. Similar phenomena have also been observed in case of Pd functionalized reduced grapheme oxide based gas sensor [64]. In spite of having huge potential of high energy EB as a tool to modify the chemiresistive gas sensing of CPs, researcher community has paid fewer attention on it for both pure CPs and its hybrid nanomaterials.…”

“…The phenomena are responsible for doping through oxidation of organic molecules which improves electrical conductivity and overall device sensitivity in case of detectors like gas sensors [64].…”

State-of-the-Art Research on Chemiresistive Gas Sensors in Korea: Emphasis on the Achievements of the Research Labs of Professors Hyoun Woo Kim and Sang Sub Kim

“…Thus, non-oxygenated defects played an important role in improving the sensing performance. Choi et al [ 130 ] reported the effect of e-beam irradiation (0, 100, and 500 kGy) on the NO 2 -sensing features of Pd-functionalized rGO. The response of the unirradiated sensor and the sensor irradiated at doses of 100 and 500 kGy to 10 ppm NO 2 were 1.027, 1.045, and 1.047, respectively.…”