Photocatalytic degradation of COVID-19 related drug arbidol hydrochloride by Ti3C2 MXene/supramolecular g-C3N4 Schottky junction photocatalyst.

Because of the current COVID-19 outbreak all over the world, the problem of antiviral drugs entering water has become increasingly serious. Arbidol hydrochloride (ABLH) is one of the most widely used drugs against COVID-19, which has been detected in sewage treatment plant sediments after the COVID-19 outbreak. However, there has been no report on the degradation of ABLH. In order to remove ABLH we prepared a novel photocatalyst composed of Ti3C2 MXene and supramolecular g-C3N4 (TiC/SCN) via a simple method. The properties of the material were studied by a series of characterizations (SEM, TEM, EDS, XRD, FTIR, UV-vis, DRS, XPS, TPC, PL, EIS and UPS), indicating the successful preparation of TiC/SCN. Results show that 99% of ABLH was removed within 150 min under visible light illumination by the 0.5TiC/SCN (containing 0.5% of TiC). The performance of 0.5TiC/SCN was about 2.66 times that of SCN resulting from the formation of Schottky junction. Furthermore, under real sunlight illumination, 99.2% of ABLH could be removed by 0.5TiC/SCN within 120 min, which was better than that of commercial P25 TiO2. The pH, anions (NO3- and SO42-) and dissolved organic matter (fulvic acid) could significantly affect the ABLH degradation. Moreover, three possible degradation pathways of ABLH were proposed, and the toxicities of the corresponding by-products were less toxic than ABLH. Meanwhile, findings showed that the superoxide radicals played a major role in the photocatalytic degradation of ABLH by 0.5TiC/SCN. This study provides a well understanding of the mechanism of ABLH degradation and provides a valuable reference for the treatment of ABLH in water.

MXene Modulated SnO2 Gas Sensor for Ultra-responsive Room-Temperature Detection of NO2

Continuous exposure to high concentration of nitrogen dioxide (NO2) severely affects the human respiratory system. Besides, NO2 has been recently observed to foster COVID-19, resulting in increased fatality rate;thus highly selective gas sensors are required for detecting NO2 at sub-ppb level. In this direction, we have synthesized two-dimensional MXene-based tin oxide (SnO2) heterostructures with varying MXene wt% (10–40wt%) using a facile hydrothermal method for room-temperature NO2 detection. The synthesized heterostructures have been structurally, optically, and electrically characterized using a suite of characterization techniques, namely, X-ray diffraction, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and Brunauer–Emmett–Teller techniques. The optimal incorporation of MXene in SnO2 nanoparticles effectively decumulates them, increasing the specific surface area of heterostructures and thereby exposing large number of adsorption sites. 20-wt% SnO2/MXene heterostructures-based sensor exhibits nearly five times higher response (231%) toward 30-ppb NO2 at room temperature with shorter response time (146s) and recovery time (102s) than pristine SnO2. Moreover, the sensor showed high selectivity, sensitivity, repeatability, reproducibility, and stable sensing response under humid conditions. The assembly of these results suggests that SnO2/MXene platform provides a pathway for realizing highly responsive NO2 sensors. Herein, possible gas sensing mechanism based on the formation of SnO2/MXene heterostructures has been discussed.