Oxalyl chloride and phosgene are highly toxic chemicals but are widely used in industrial processes, which have been regarded as a serious threat to our health and public security. Thus, it is imperative to develop a convenient and reliable detection method for these noxious agents. In this research, we report the rational design of a fluorescent sensor (denoted as BTA) for simultaneously detecting oxalyl chloride and phosgene, in which o-phenylenediamine (OPD) as the reactive recognition site and benzothiadiazole (BTD) as the fluorophore moiety are coupled into one single benzo-fused motif. The probe works in a “turn-on” fluorescence mode due to the formation of piperazine-2,3-dione and 2-imidazolidinone rings by intramolecular cyclization reactions between the OPD part with oxalyl chloride and phosgene, respectively, which greatly inhibits the intramolecular charge transfer (ICT) process from two amines to the BTD core in the sensor BTA. The detection limit of oxalyl chloride and phosgene is as low as 3 nM and 20 nM in solutions, respectively. Moreover, the sensor exhibits outstanding selectivity toward oxalyl chloride and phosgene over the nerve-agent mimic diethyl chlorophosphate and various acyl chlorides. Furthermore, a portable test paper with BTA has been facilely fabricated for visual on-site detection of the two toxic chemicals in the gas phase.

A benzothiadiazole-based fluorescent sensor for selective detection of oxalyl chloride and phosgene

Adsorption of phosgene molecule on the transition metal-doped graphene: First principles calculations

The advances in cluster-assembled materials where clusters serve as building blocks have opened new opportunities to develop ever more sensitive gas sensors. Here, using density functional theory calculations, the structural and electronic properties of cluster-assembled nanowires based on M12N12 (M = Al and Ga) clusters and their application as gas sensors have been investigated. Our results show that the nanowires can be produced via the coalescence of stable M12N12 fullerene-like clusters. The M12N12-based nanowires have semiconducting electrical properties with direct energy gaps, and are particularly stable at room temperature for long enough to allow for their characterization and applications. Furthermore, we found that the CO, NO, and NO2 molecules are chemisorbed on the M12N12-based nanowires with reasonable adsorption energies and apparent charge transfer. The electronic properties of the M12N12-based nanowires present dramatic changes after the adsorption of the CO, NO, and NO2 molecules, especially their electric conductivity. However, the adsorption of NO2 on the Al12N12-based nanowire is too strong, indicating an impractical recovery time as NO2 sensors. In addition to this, due to reasonable adsorption energies, apparent charge transfer, change in the electric conductivity, and the short recovery time, the Al12N12-based nanowire should be a good CO and NO sensor with quick response as well as short recovery time, while the Ga12N12-based nanowire should be a promising gas sensor for CO, NO, and NO2 detection.

The cluster-assembled nanowires based on M12N12 (M = Al and Ga) clusters as potential gas sensors for CO, NO, and NO2 detection

Graphdiyne nanosheets as a sensing medium for formaldehyde and formic acid – A first-principles outlook

In this work, the adsorption of phosgene (COCl2) gas on the outer surface of Al12N12, Al12P12, B12N12 and B12P12 pristine nanoclusters is studied with regard to different aspects, including energetic, geometric and electronic properties, using the M06-2X/B97D/B3LYP//6-311g(d,p) levels of theory. The adsorption energies of phosgene molecule on the exterior surface of pure Al12N12, Al12P12, B12N12 and B12P12 nanoclusters are − 0.816, − 0.272, − 0.272 and − 0.272 eV, with optimum distances of 2.01, 3.77, 2.52, and 3.42 A, respectively. Our results show that these combinatorial nanoclusters are able to adsorb the phosgene molecule via exothermic processes. It is demonstrated that by increasing the quantity of phosgene gas, the adsorption energy becomes less negative (except in the case of Al12P12). The Al12N12 nanocluster is more sensitive to phosgene gas than the other nanoclusters.

A Comparative Computational Investigation of Phosgene Adsorption on (XY)(12) (X=Al, B and Y=N, P) Nanoclusters: DFT Investigations

To find a novel sensor for phosgene molecules, phosgene adsorption on Al12N12 nanocage was studied by using density functional calculations in terms of geometry, Gibbs free energy, energy gap, enth...

HashemianSaeedeh

Papers

Al12N12 nanocage as a potential sensor for phosgene detection