The structural catalyst CuMoO4/TiO2/TiO2Â +Â SiO2/Ti for diesel soot combustion

A Ti surface treated by plasma electrolytic oxidation (PEO) in silicate electrolyte has been coated with the nanostructural TiO2 layer and then impregnated using the sol-gel method with Cu and Mo, which are active ingredients for soot combustion. The layer TiO2 consists of anatase crystals of up to 50 nm, and has a mosaic-like structure with interconnected surface cracks. The quantity and volume of microcracks depend on both a concentration of the TiO2 colloidal suspension and a regime of its heat treatment. After impregnation with Cu and Mo and calcination at 550 °С, the surface of the TiO2 layer is evenly covered by the CuMoO4 particles of 150-350 nm. The catalytic performance for diesel soot combustion was analyzed under loose contact conditions of soot and catalyst. The structured catalysts CuMoO4/TiO2/TiO2 + SiO2/Ti provide diesel soot combustion above 280 °С with two maximum rates of 340-360 °С (soot combustion in volume of microcracks) and 397-405 °С (soot combustion on flat sides of a surface). The PEO coating on the titanium substrate showed a good adherence when subjected to an ultrasonic test, and improved after using weakly concentrated colloidal suspension for the formation of a thin TiO2 layer.