Chemical warfare agent simulant DMMP reactive adsorption on TiO2/graphene oxide composites prepared via titanium peroxo-complex or urea precipitation

Abstract

Two water-based methods were used to produce TiO₂/graphene oxide (GO) nanocomposites with 1 and 2 wt.% GO. Both procedures exclude the use of organometallic precursors, as well as the high-pressure and high-temperature treatments, which facilitate pure and energy efficient synthesis amenable for larger scale synthesis. Nanocomposites with narrow (<10 nm) and long spindle-like (<100 nm) TiO₂ nanoparticles supported on GO flakes were obtained (TiO₂/GO), and their properties for reactive destruction of the organophosphorus simile chemical warfare agent (CWA) dimethyl methylphosphonate (DMMP) were investigated by in situ DRIFTS spectroscopy. Both synthesis procedures yielded highly reactive nanocomposites with markedly different properties compared to similarly prepared pure TiO₂ nanoparticles. GO also induced morphology and texture changes, which were observed to have a significant impact on the adsorption and reactivity of the nanocomposites, and which were strongly related to synthesis procedure. In particular, the reduction state of GO, as measured by Raman spectroscopy, was observed to play a major role for the reactivity of the TiO₂/GO nanocomposites.

Keywords: Chemical warfare agents; Graphene oxide; In situ DRIFT spectroscopy; Organophosphates; TiO(2).