Easy synthesis of three-dimensionally ordered macroporous La 1−xK xCoO 3 catalysts and their high activities for the catalytic combustion of soot

Abstract

Three-dimensionally ordered macroporous (3DOM) La 1− x K x CoO 3 ( x = 0–0.3) perovskite-type oxide catalysts with large pore sizes and interconnected macroporous frameworks were successfully synthesized by a novel method of carboxy-modified colloidal crystal templates (CMCCT). The obtained catalysts were characterized by means of XRD, FT-IR, SEM, TEM, BET, XPS, and H 2 TPR. The detailed preparation process was investigated using in situ TG–DSC, Raman, and EDS analyses. The sp 2-hybridized carbon atoms of the modified polymer templates can be converted to sturdy amorphous carbon materials by calcination under an inert atmosphere to prevent the macrostructure from collapsing. The active site densities of catalysts were determined by isothermal anaerobic titration, and their turnover frequency (TOF) values were then calculated. The catalytic performances for soot combustion were evaluated using temperature-programmed oxidation (TPO) reaction technology. 3DOM La 1− x K x CoO 3 catalysts exhibited catalytic activities as high as that of noble metal Pt catalysts under loose contact conditions.