Adsorption of sarin on MgO nanotubes: Role of doped and defect sites

• Most stable conformer of sarin was determined.
• Structural and electronic characteristics of MgO nanotube modify on doping with Ti.
• Adsorption of sarin is exothermic on both perfect and Ti-doped MgO nanotubes.
• Adsorption of sarin on defect sites of MgO nanotube was studied.
• Sarin decomposes destructively on oxygen and MgO defect sites.
• Our research on decomposition of sarin on this different form of nanosurface, i.e., MgO nanotube, can pave the way for designing a novel decontamination system.

Sarin is a highly toxic organophosphorus chemical warfare agent which has been employed in various wars and terrorist attacks. Due to an urgent need of finding safe methods to decompose this toxic nerve agent, the research on decomposition of sarin gains importance. In the present work, the decomposition of sarin molecule on MgO nanotube and Ti-doped MgO nanotube has been investigated. For this purpose, the structural and electronic characteristics of nanotubes are first examined. It is seen that although doping with Ti modifies the properties of the nanotube, adsorption of sarin on both kinds of nanotubes presents similar characteristics. Adsorption is found to be more favorable at low-coordinated sites, i.e., the 3c site is preferred over 4c. Five kinds of surface defect sites have been considered i.e., O4c, O4c2−, Mg4c, Mg4c2+ and (MgO)4c. Adsorption of sarin on various defect sites produces different products. In two of the cases, the neutral oxygen defect and MgO defect, the molecule breaks completely into fragments and is destructively decomposed. Hence, our study proposes a new metal oxide system that might destructively adsorb chemical warfare agents and highlights the need for further exploration of untested metal oxide systems.