Adsorption behavior analysis of CNCl on transition metal-doped fluorinated diamanes: A first-principles study

Cyanogen chloride (CNCl) is a toxic chemical that poses significant risks to human health and the environment; therefore, its level must be accurately monitored. Herein, the adsorption of CNCl by transition metal-doped fluorinated diamanes (F-diamanes) has been extensively studied via first-principles calculations. Key parameters such as adsorption energies, charge transfer amounts, bandgaps, sensitivity, densities of states, projected density of states, charge density differences, and recovery time were systematically analyzed. Results reveal that monometallic doping significantly enhances CNCl adsorption, with increases in adsorption energy by 164%–368% and charge transfer by 1234%–1571%, particularly in the AuFD-CNCl, AgFD-CNCl, and CuFD-CNCl systems, which demonstrated improved sensing performances. Similarly, bimetallic co-doping further strengthened adsorption, with energy enhancements of 277%–309% and charge transfer increases of 1238%–1505%. Au-CuFD-CNCl, Au-AgFD-CNCl, and Cu-AgFD-CNCl systems also showed superior sensing performances. Meanwhile, the recovery time of CNCl molecules on the AuFD, AgFD, Au-CuFD, and Au-AgFD surfaces was drastically reduced to acceptable levels at 279–412 K, leading to their desorption. Therefore, these four systems exhibited excellent reversibility properties, suggesting their applicability in gas-sensing applications. This work can facilitate the applications of doped F-diamanes in environmental conservation, energy storage, and chemical engineering.