Continuous hydrothermal flow syntheses of transition metal oxide doped CexTiO2 nanopowders for catalytic oxidation of toluene

A series of transition metal oxides doped CexTiO2 samples were synthesized using a continuous hydrothermal flow synthesis (CHFS) method. The resultant samples were then investigated using a range of analytical methods, including XPS, X-ray powder diffraction, H2-TPR, TEM and BET surface area measurements. Experimental results showed that the samples were highly crystalline with remarkably high surface areas (in the range of 200–300 m2 g−1), which were ca. two-fold higher than those synthesized via more conventional routes. The Ce0.05TiO2 sample revealed a good catalytic performance in toluene oxidation, which was subsequently utilized for the optimization of transition metal oxide doping. After screening MnOx, CrOx and CuOx doping, it was found that they had all led to significant enhancements in the activity for toluene conversion, particularly for CuOx doped sample, which showed a superior performance (T90 = 200 °C) for toluene oxidation, comparable to some noble metal catalysts.