Thin and ultrathin films of palladium oxide for oxidizing gases detection

The fabrication of reliable and cost‐effective gas sensor for low concentrations of toxic gases such as ammonia is still a challenging task, in this work the authors report structural, topography, and optical properties of pure and Ba‐doped Mn3O4 thin films prepared by chemical spray pyrolysis (CSP) as well as its gas sensing performance toward low concentrations of ammonia gas. XRD analyses prove the films have tetragonal spinel structure with a preferred orientation along the direction (103). AFM and SEM measurements show the films have homogeneous with rough surfaces and porous structures. EDS measurement confirms the presence of Mn, O, and Ba elements according to a doping concentration ratio. Optical measurements show the optical band gap redshifts and the bond length expands as Ba concentration increases. The optimal results are achieved in Mn3O4:Ba1% thin films where porous structure, rough surface, high crystallinity, and maximum response toward (20, 30, 40, and 50 ppm) of ammonia gas with great stability. Empirical equations are suggested to evaluate the sensitivity in terms of relative bond length and RMS roughness. These results show the films are good candidates in p‐type MOS gas sensors.

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“…Furthermore Figure shows an excellent coincidence with the experimental data and fairly agree with the work reported in literature …”

Section: Resultssupporting

confidence: 92%

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Najim

Darwoysh

Dawood

et al. 2018

Physica Status Solidi (a)

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“…As it can be seen in Figure 10, at the process of NO 2 quantitative detection within concentration interval 500 ppb-200 ppm, PdO ultrathin films have demonstrated good values of sensor response, signal stability, and reproducibility of sensor response [51]. It is necessary to note that the recovery period at NO 2 detection is longer than that at O 3 detection (Figures 7, 8, and 10).…”

Section: Gas Sensor Properties Of Palladium (Ii) Oxide Nanostructuresmentioning

confidence: 93%

“…It has been established that PdO thin and ultrathin film sensors gave the stable signal, and the resistance values reliably returned to the baseline at SA atmosphere [50,51]. It is necessary to note that the recovery period is quite long (600-700 s).…”

Section: Gas Sensor Properties Of Palladium (Ii) Oxide Nanostructuresmentioning

confidence: 99%

Palladium (II) Oxide Nanostructures as Promising Materials for Gas Sensors

Samoylov¹,

Ryabtsev²,

Popov³

et al. 2018

Novel Nanomaterials - Synthesis and Applications

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One of the most important environment monitoring problems is the detection of oxidizing gases in the ambient air. Negative impact of noxious oxidizing gases (ozone and nitrogen oxides) on human health, sensitive vegetation, and ecosystems is very serious. For this reason, palladium (II) oxide nanostructures have been employed for oxidizing gas detection. Thin and ultrathin films of palladium (II) oxide were prepared by thermal oxidation at dry oxygen of previously formed pure palladium layers on polished poly-Al 2 O 3 , SiO 2 /Si (100), optical quality quartz, and amorphous carbon/KCl substrates. At ozone and nitrogen dioxide detection, PdO films prepared by oxidation at T = 870 K have demonstrated good values of sensitivity, signal stability, operation speed, and reproducibility of sensor response. In comparison with other materials, palladium (II) oxide thin and ultrathin films have some advantages at gas sensor fabrication. Firstly, for oxidizing gas detection, PdO films with p-type conductivity are more perspective than the material with n-type conductivity. Secondly, at ambient conditions, palladium (II) oxide is insoluble in water and does not react with it. These facts are favorable for the fabrication of gas detectors because they make possible to minimize the air humidity influence on PdO sensor response values. Thirdly, the synthesis procedure of PdO films is rather simple and is compatible with planar processes of microelectronic industry.

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“…The catalytic activity of Pd NPs enhanced the NO 2 molecule adsorption and thereby enhanced the sensor response, so a PS/WO 3 –Pd60 sensor having the highest amount of Pd NPs showed the highest sensor response at room temperature ( Figure 3 C). With a facile fabrication process and being compatible with the planar processes of the microelectronics industry, ultra-thin PdO films provided good sensing performances toward NO 2 [ 85 ], but they require a long recovery period (600–700 s) because of the lack of immediate interaction between NO 2 molecules and oxygen molecules adsorbed on sensor material surface. Also, ZnO nanostructured films obtained by a thermal evaporation method offered significantly enhanced response (622 at 100 ppm NO 2 ) with good response-recovery at 200 °C [ 86 ].…”

Section: Recent Advances In No 2 Gas Detectionmentioning

confidence: 99%

Recent Advances in Electrochemical Sensors for Detecting Toxic Gases: NO2, SO2 and H2S

Khan

Rao

2019

Sensors

282

100

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Toxic gases, such as NOx, SOx, H2S and other S-containing gases, cause numerous harmful effects on human health even at very low gas concentrations. Reliable detection of various gases in low concentration is mandatory in the fields such as industrial plants, environmental monitoring, air quality assurance, automotive technologies and so on. In this paper, the recent advances in electrochemical sensors for toxic gas detections were reviewed and summarized with a focus on NO2, SO2 and H2S gas sensors. The recent progress of the detection of each of these toxic gases was categorized by the highly explored sensing materials over the past few decades. The important sensing performance parameters like sensitivity/response, response and recovery times at certain gas concentration and operating temperature for different sensor materials and structures have been summarized and tabulated to provide a thorough performance comparison. A novel metric, sensitivity per ppm/response time ratio has been calculated for each sensor in order to compare the overall sensing performance on the same reference. It is found that hybrid materials-based sensors exhibit the highest average ratio for NO2 gas sensing, whereas GaN and metal-oxide based sensors possess the highest ratio for SO2 and H2S gas sensing, respectively. Recently, significant research efforts have been made exploring new sensor materials, such as graphene and its derivatives, transition metal dichalcogenides (TMDs), GaN, metal-metal oxide nanostructures, solid electrolytes and organic materials to detect the above-mentioned toxic gases. In addition, the contemporary progress in SO2 gas sensors based on zeolite and paper and H2S gas sensors based on colorimetric and metal-organic framework (MOF) structures have also been reviewed. Finally, this work reviewed the recent first principle studies on the interaction between gas molecules and novel promising materials like arsenene, borophene, blue phosphorene, GeSe monolayer and germanene. The goal is to understand the surface interaction mechanism.

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Thin and ultrathin films of palladium oxide for oxidizing gases detection

Cited by 24 publications

References 44 publications

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Palladium (II) Oxide Nanostructures as Promising Materials for Gas Sensors

Recent Advances in Electrochemical Sensors for Detecting Toxic Gases: NO2, SO2 and H2S

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Thin and ultrathin films of palladium oxide for oxidizing gases detection

Cited by 24 publications

References 44 publications

Structural, Topography, and Optical Properties of Ba‐Doped Mn3O4 Thin Films for Ammonia Gas Sensing Application

Structural, Topography, and Optical Properties of Ba‐Doped Mn3O4 Thin Films for Ammonia Gas Sensing Application

Palladium (II) Oxide Nanostructures as Promising Materials for Gas Sensors

Recent Advances in Electrochemical Sensors for Detecting Toxic Gases: NO2, SO2 and H2S

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Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application

Structural, Topography, and Optical Properties of Ba‐Doped Mn₃O₄ Thin Films for Ammonia Gas Sensing Application