Toluene catalytic oxidation over the layered MO_x - δ-MnO_2 (M = Pt, Ir, Ag) composites originated from the facile self-driving combustion method

摘要

A series of layered manganese oxides catalysts were successfully prepared by self-driving combustion (SDC) technology using potassium permanganate and citric acid as precursors and evaluated in the catalytic activity of toluene. The temperature for 90% removal of toluene (T-90) and total combustion (WHSV = 30000 mL g(cat)(-1) h(-1)) are separately 252 and 300 degrees C, which exhibits comparable performance to our previous reported noble metal catalysts. In order to achieve a better catalytic activity of manganese-based catalyst at the lower operating temperatures, noble metals (Pt, Ir, and Ag) were employed to modulate the obtained manganese oxide matrix to synthesize new nanocatalysts by using the synergistic catalytic effects that are distinct from those of their parent active phase. It was found that 0.5Pt-SDC-13 displays the highest catalytic performance among the noble metal modified Mn-based catalysts, in which T-90 was achieved at 228 degrees C. The improved activity for Mn-based catalysts should be attributed to the change in key factors such as Mn valence state, lattice oxygen density and its mobility. Therefore, the SDC technology provides an effective pathway to exploit efficient and low energy consumption catalysts carrier for the degradation of VOCs.