In the context of the increase in chemical threat due to warfare agents in terms of terrorist chemical attacks as well as of accumulation in stockpiles, the development of efficient methods for destruction of Chemical Warfare Agents (CWA) is of first importance for both civilian and military purposes. Here, we present innovative Ta-TiO2 doped photocatalysts able to lead to the total elimination of highly contaminated environments containing diethylsulfide (DES) used as a simulant of CWA, namely of Yperite (Mustard Gas). It has been shown that the Ta doping could induce significant modifications on the structural, morphological, surface, electronic and optical properties of TiO2. Optimization of the Ta loading in the doped material as well as of the calcination temperature led to excellent performances toward the elimination of high concentrations of DES (1200 ppmv, i.e. 5 g/m(3) of air) contained in air under UV-A irradiation. Total DES elimination could be reached for 100 min under continuous contaminant flux before deactivation and the conversion maintained to 80% of degradation after 200 min. Correlations between the resulting physicochemical properties of the doped material and the photocatalytic activity have been proposed and reaction mechanism pathways have been suggested. The results open up an extremely promising way for the use of Ta-doped TiO2 photocatalysts for the decontamination of highly contaminated environments containing real warfare agents under UV-A irradiation but also under visible or solar light illumination. (C) 2015 Elsevier Inc. All rights reserved.