Effect of alkali metal cation on catalytic activity of TiO2-supported copper catalyst derived from copper(II) chloride for combustion of diesel particulate

Effect of alkali metal cation as an additive in catalytic combustion of Die sel particulate matter (PM) was investigated using TiO2-supported copper ca talysts(M, Cu/TiO2, M: alkali metal ion) derived from copper(II) chloride(C uCl2, 2H(2)O) by the addition of Na+, K+, Rb+ and Cs+ ions, respectively. M , Cu/ TiO2 catalysts except for Na, Cu/TiO2 showed good catalytic performan ce of the PM combustion below 620 K, especially in recycle use. This is att ributed to that the presence of compounds consists of M-CuCl promoted the i ntimate contact between MCl and Cu species after the decomposition of M-Cu- Cl. Since K, Cu/TiO2 among M, Cu/TiO2 catalysts was superior in combustion temperature, potassium is presumed to act favorably for the oxidation of PM .