Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector
Rapid chemiresistive detection of p-nitrophenol through Porphyrin-functionalized 2D materials: a step toward environmental monitoring
Chemiresistive gas sensors have gained attention due to their simple device structure, portability, easy fabrication, and operation. However, one of the major drawbacks of these sensors is their lack of selectivity and low sensing response. The p–n junction-based vapor sensors are gaining significant attention all over the world for their enhanced sensing response and selectivity toward vapor sensing compared to ohmic contact-based chemiresistive sensors. In the present work, attempts have been made to develop the p–n junction-based chemiresistive sensor through interface modulation of nano graphite platelets (NGPs) using functionalized two-dimensional (2D) materials, resulting in the formation of a p–n junction. The nanocomposite sensor has been developed through octaethyl cobalt porphyrin-functionalized nano graphite platelets (OEP-Co-NGPs) (n-type) with tungsten disulfide nanoparticles (WS2 NPs) (p-type) and analyzed with multiple characterization techniques, including Raman spectroscopy, X-ray diffractometer (XRD), scanning electron microscopy (SEM), contact angle, etc. In this work, both NGPs/WS2 and OEP-Co-NGPs/WS2 sensors have been employed for para-nitrophenol (p-NP) vapor detection. The experimental results demonstrated that the OEP-Co-NGPs/WS2 sensor exhibited an excellent sensing response toward selective detection of p-nitrophenol (p-NP). The creation of the p–n junction through porphyrin-functionalized NGPs into heterostructure has significantly improved the sensing response as compared to the sensor prepared through non-functionalized NGPs. The OEP-Co-NGPs/WS2 sensor exhibited excellent selectivity even in the presence of inferring gas species, low limiting detection of 0.0459 ppb, excellent repeatability, reproducibility (relative standard deviation (RSD)-0.845%), long-term stability (RSD?<?3.01%), and outstanding linearity (coefficient of correlation (R2)—0.909). It also showed a high tolerance to humidity due to the hydrophobic nature of OEP-Co-NGPs. Further, the charge transport mechanism has been studied through a variable range hopping (VRH) model along with the temperature-dependent electrical conductivity of the OEP-Co-NGPs/WS2 nanocomposite. Thus, the n–p junction-based OEP-Co-NGPs/WS2 chemiresistive sensor has the potential to be used as a novel p-NP vapor detector that provides excellent performance with good tolerance to environmental humidity.
Graphical abstract
» Publication Date: 23/02/2024
This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº 768737
