Layered double hydroxides: Novel nanocatalysts for combustion of gaseous toluene from polluted air

The catalytic performance of Ni-Al, Mg-Al, and Co-Ni LDHs as novel nanocatalysts was evaluated in the oxidation of toluene. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The XRD and FTIR approved the structure and functional groups of the LDH, respectively. Also, the presence of cations with different oxidation state confirmed by XRD. According to this result, Mars Van Krevelen (MVK) mechanism was suggested for the combustion of toluene over the LDH nanocatalysts. The SEM results indicated that the nanostructure and layered morphology of the catalysts. All LDHs exhibited catalytic activity for toluene oxidation. T80 (temperature for 80% conversion for toluene) for Co-Ni, Ni-Al and Mg-Al LDH catalysts were 225, 277 and 350 °C, respectively. So, the Co-Ni LDH showed the highest activity. Furthermore, Ni-Al LDH exhibited the highest thermal stability. So, we concluded that Ni-Al LDH is a superior catalyst for toluene oxidation in the studied series.