However, the conventional techniques required complex instrumentations, long sampling time, high expensive and large energy consumption are main factors limiting their usage in real-time monitoring ( Chung et al., 2013 Vikrant et al., 2018a Vikrant et al., 2018b). In addition, various conventional techniques such as gas chromatography (GC) ( Zhu et al., 2019), high-performance liquid chromatography (HPLC) ( Schenk et al., 2019), spectrophotometry ( Möhlmann, 1985), polarography ( Septon and Ku, 1982), and ion chromatography ( Lorrain et al., 1981) have been used to measure gaseous HCHO.
The precise assessment and rapid identification of concentrations of HCHO offers valuable information that can be further used to control the IAP. In light of such circumstances, the Occupational Safety and Health Administration (OSHA) has estimated the limit for HCHO exposure is 0.75 ppm ( Na et al., 2019). Similarly, exposure to various VOCs, including formaldehyde (HCHO), for prolonged time leads to leukemia and nasopharyngeal cancer due to its mutagenic nature ( Hopkinson and Schofield, 2018 Möhner et al., 2019).
#HR XPS PEAK PD 3D SKIN#
Therefore, high indoor concentrations of VOCs cause building sickness syndromes, such as headaches, nausea, throat, nasal pain, breathing difficulties, cough, asthma, skin irritation, vomiting, and eczema ( Na et al., 2019 Nag, 2019). It is estimated that the indoor concentrations of these pollutants are 5–10 times higher than outdoor concentrations ( Ligotski et al., 2019 Sarigiannis et al., 2019). The presence of many IAP-related pollutants such as volatile organic compounds (VOCs) in the construction materials, consumer products, household furnishings, paints, and their insufficient ventilation from buildings are considered dangerous components for human survival ( Huang et al., 2016 Na et al., 2019). Therefore, this MOF-driven strategy can prepare metal oxide composites with high surface area, well-defined morphology, and satisfactory room-temperature formaldehyde gas sensing performance for indoor air quality control.Ĭonsidering the time people spend indoors (e.g., up to 80% of an individual’s life span) ( Abdullah et al., 2019 Kelly and Fussell, 2019 Majd et al., 2019) but there exist indoor air pollution (IAP) is a challenging and vital problem for people’s health. Besides, due to the catalytic effect of Pd and PdO, the adsorption and desorption of the gas molecules are accelerated, and the response and recovery time is as small as 256 and 264 s, respectively. As the height of the energy barrier at the junction of exponentially influences the sensor resistance, the nanomaterials exhibit high sensitivity (38.57% for 100 ppm) at room temperature for 1-ppm formaldehyde with satisfactory selectivity towards (ammonia, acetone, methanol, and IPA). More importantly, intensive inside the material and composite interface provides lots of p-n heterojunction to efficiently manipulate room temperature sensing performance. During the calcination procedure, an optimized temperature of 500☌ was used to form a stable structure. Specifically, porous nanomaterials with large surfaces were synthesized using MOFs as sacrificial templates. Herein, metal-organic framework (MOF) derived porous nanostructures were synthesized through hydrothermal method followed by calcination processes. College of Electronics and Information Engineering, Shenzhen University, Shenzhen, ChinaĪs formaldehyde is an extremely toxic volatile organic pollutant, a highly sensitive and selective gas sensor for low-concentration formaldehyde monitoring is of great importance.Faheem Ullah Khan, Shahid Mehmood, Shiliang Liu, Wei Xu, Muhammad Naeem Shah, Xiaojin Zhao, Junxian Ma, Yatao Yang* and Xiaofang Pan*