Metal-Decorated Phthalocyanine Monolayer as a Potential Gas Sensing Material for Phosgene: A First-Principles Study

[Image: see text] Research into a gas sensing material with excellent performance to detect or remove toxic phosgene (COCl(2)) is of great significance to environmental and biological protection. In the present work, the adsorption performance of COCl(2) on pristine phthalocyanine (Pc) and metal-decorated Pc (MePc, Me = Cu, Ga, and Ru) monolayers was studied by first-principles calculations. The results show that the absorption process of COCl(2) on pristine Pc and CuPc both belong to physisorption, indicating that they are not suitable gas sensing materials for COCl(2). When Pc sheets are decorated by Ga and Ru atoms, the adsorption of COCl(2) is changed into chemisorption, and the corresponding adsorption energies are −0.57 and −0.50 eV for GaPc and RuPc, respectively. The microcosmic mechanism between COCl(2) and adsorbents (GaPc, RuPc) was clarified by the analysis of the density of states, the charge density difference, and the Hirshfeld charge. In addition, the COCl(2) adsorption results in a significant conductivity variation of the RuPc monolayer, demonstrating it exhibits a high sensitivity to the COCl(2) molecule. Meanwhile, quick desorption processes were noticed at various temperatures for the COCl(2)/RuPc system. Consequently, the RuPc monolayer can be considered as a potential candidate for phosgene sensors because of the moderate adsorption strength, high sensitivity, and fast desorption speed.