Degradation of chemical warfare agents by nickel doped titanium dioxide powders: Enhanced surface activity

Abstract

Here, Nickel doped anatase TiO2 samples were prepared and characterized by X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, specific surface area (BET), porosity determination (BJH) and CO2-TPD experiments. DFT calculation was conducted to investigate the oxygen vacancy formation energies and hydroxyl groups activity. The as-prepared Ni2+ doped TiO2 samples were used for heterogeneous degradation of chemical warfare agents (CWAs) and a high degradation rate, 92.2% and > 99.5% for sulfur mustard (HD) within 1 h and 12 h, > 99.5% for soman (GD) in less than 30 min, and > 99.5% for VX in less than 5 min was achieved, which were significantly enhanced compared with commercial P25 and anatase TiO2 nanoparticles under identical conditions. The formation of non-toxic hydrolysis products confirmed the nucleophilic hydrolysis pathway via surface reaction. Integration of experimental and computational methods could well illustrate that surface structure changes of TiO2 after Ni2+ doping was the main reason for the superior stoichiometric activity towards CWAs.

Keywords

• Anatase titania
• Nickel
• Heterogeneous reaction
• Chemical warfare agents degradation
• Surface hydroxyl groups