Cobalt carbide nanosheets as effective catalysts toward photothermal degradation of mustard-gas simulants under solar light

Abstract Here, ultrathin cobalt carbide (Co2C) nanosheets are firstly illustrated as effective and robust catalysts toward photothermal degradation of sulfur mustard simulants (e.g., 2-chloroethyl ethyl sulfide, CEES) under solar light. Under the optimal conditions, the degradation rate of CEES by Co2C nanosheets is up to 98 %, which is much higher than the widely used P25 and anatase TiO2 nanoparticles. Moreover, the degradation performance is comparable or even better than those typical photothermal catalysts, including MnO2, MnOx-TiO2 and Co3O4, under identical conditions. Experimental evidences and density functional theory (DFT) calculations reveal that the superior activity is attributed to three main reasons: (i) the high photo-to-heat conversion efficiency of Co2C enables an elevated surface temperature for chemical bond breaking, (ii) the feasible binding of CEES on Co2C surface via Co S and Co Cl coordination promotes the process of degradation, and (iii) the surface hydroxyl groups ( OH) on Co2C nanosheets favor the degradation of CEES. Obviously, this work provides new insights into practical and large-scale application of transition metal carbides (TMCs) as novel photothermal catalysts in the decontamination of chemical warfare agents (CWAs) under ambient conditions (i.e., solar light and room temperature).