Recent Advances in Gas Detection Methodologies with a Special Focus on Environmental Sensing and Health Monitoring Applications─A Critical Review. | LitMetric
With the expansion of the Internet-of-Things (IoT), the use of gas sensors in the field of wearable technology, smart devices, and smart homes has increased manifold. These gas sensors have two key applications─one is the detection of gases present in the environment and the other is the detection of Volatile Organic Compounds (VOCs) that are found in the breath. In this review, we focus systematically on the advancements in the field of various spectroscopic methods such as mass spectrometry-based analysis and point-of-care approach to detect VOCs and gases for environmental monitoring and disease diagnosis. Additionally, we highlight the development of smart sensors that work on the principle of electrochemical detection and provide examples of the same through an extensive literature review. At the end of this review, we highlight various challenges and future perspectives.
It is well known that metals and metal oxides with different crystal facets exhibit varying sensitivity in gas sensors, but this strategy is rarely used in metal-organic frameworks (MOFs). Herein, we proved for the first time that Cu metal-organic with high energy crystal facets (Cu-MOF-74-300) shows a much higher sensitivity than the low energy crystal facets (Cu-MOF-74-110), with a up to 2 times response more than Cu-MOF-74-110 and ultra-low limit of detection (LOD) of 68 ppb to toluene vapors. In addition, this strategy was further demonstrated on MOF-14 and HKUST-1, which are also Cu-centered and exhibit clear recognition effects on benzene and xylene, respectively.
The rapid advancement of the Internet of Things has created a substantial demand for portable gas sensors. Nevertheless, the development of gas sensors that can fulfill the demanding criteria of high sensitivity and rapid response time continues to pose a considerable challenge. Herein, an in-situ anchoring strategy is proposed to construct CNTs@MOF heterostructure to establish strong electronic coupling and charge relocation for enhancing the monitoring capabilities of isopropanol (freshness markers for fruits) at room temperature.
Piezoelectric resonance sensors are essential to many diverse applications associated with chemical and biological sensing. In general, they rely on continuously detecting the resonant frequency shift of piezoelectric resonators due to analytes accreting on their surfaces in vacuum, gas or fluid. Resolving the small analyte changes requires the resonators with a high quality factor.
Mastering the surface chemistry of quantum dots (QDs) has enabled a remarkable gas-sensing response as well as impressive air stability. To overcome the intrinsic receptor-transducer mismatch of QDs, PbS QDs used as sensitive NO receptors are spin-coated on top of a few-layer MoS and incorporated into a thin-film transistor (TFT) gas sensor. This architecture enables the separation of the electron transduction function from the chemical reception function.
With the increasing demand for food safety monitoring, the development of efficient, convenient, and green gas sensors has become a current research hotspot. Triboelectric nanogenerator (TENG) as a triethylamine sensor is a cutting-edge strategy for detection without the need for an additional power source. In this study, synthesized WO/MXene materials were prepared and bilayer thin films of carbon quantum dots (CPDs)-WO/MXene TENG.
