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Glucose-free and glucose-containing LaCoO3(-G), La0.9Sr0.1CoO3(-G), and La0.9Ce0.1CoO3(-G) perovskite catalysts were synthesized via the sol–gel method, over which the oxidation performance of high-concentration CO was investigated. The experimental results indicate that the catalytic activity can be improved by facilely adding glucose during the preparation where glucose creates a reducing atmosphere and takes away the oxygen atoms of perovskites to form more oxygen vacancies and Co3+. CO self-sustained combustion is favorably achieved and La0.9Ce0.1CoO3-G shows the best catalytic performance. Combining the XPS, H2-TPR, O2-TPD and CO-TPD results, the outstanding performance of La0.9Ce0.1CoO3-G is mainly ascribed to the relatively higher concentrations of Co3+, Ce3+ and oxygen vacancies. The reaction was found to follow the Langmuir–Hinshelwood (L–H) mechanism by in situ IR spectroscopy and kinetic results. Furthermore, La0.9Ce0.1CoO3-G exhibits good high-temperature durability with unchanged CO conversion of 100% at 760 °C. It is suggested that the addition of glucose and the impregnation of Sr or Ce in perovskites is a feasible strategy to design industrial catalysts for CO self-sustained combustion. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The catalytic self-sustained combustion of toluene was successfully developed. • CuCeZr/TiO 2 catalyst showed the excellent performance in self-sustained combustion. • TPO in N 2 atmosphere was used to investigate the role of lattice oxygen in toluene combustion. Abstract The catalytic self-sustained combustion of toluene over Cu x Mn 1-x Ce 0.75 Zr 0.25 /TiO 2 catalysts (x = 1, 0.5, 0) was studied in a microscale combustor. The catalytic activity is determined not only by the temperature with toluene conversion of 90% (T co), but also by the corresponding lean-combustion limits. It was found that the self-sustained combustion was achieved successfully over the catalysts, with the toluene concentrations of 0.35 con.%, 0.50 con.% and 1.00 con.%. According to T co, the activity decreased in the order of CuCe 0.75 Zr 0.25 /TiO 2 (234 °C)＞Cu 0.5 Mn 0.5 Ce 0.75 Zr 0.25 /TiO 2 (238 °C) ＞MnCe 0.75 Zr 0.25 /TiO 2 (284 °C). The excellent activity of CuCe 0.75 Zr 0.25 /TiO 2 catalyst could be ascribed to the high content of active lattice oxygen, good low-temperature reducibility and homogeneous dispersion, combined with the results of H 2 -TPR, O 2 -TPD and XPS. Furthermore, the results of in-situ DRIFT and temperature-programmed oxidation (TPO) of toluene in N 2 atmosphere suggested that toluene was adsorbed on the catalyst surface by removing α-H from methyl and combining with active oxygen specie to form benzyl group, which was finally oxidized into CO 2 and H 2 O with lattice oxygen. [ABSTRACT FROM AUTHOR]

• Ea of intermediate species is calculated during toluene oxidation. • Relationship between the activation energy of the overall and primitive reaction. • Transient response experiments of isotopically labeled oxygen. • M−K mechanism dominates in the oxidation of toluene. Catalytic properties of multiple metals deposited on TiO 2 nanoparticles were investigated in the oxidation of toluene. Isovolume impregnation method prepared the catalysts containing Cu, Mn, Ni, Co, and Fe deposited on TiO 2 , including CeO 2 and ZrO 2. The effects of loaded metal oxides on the structure and activity of initial catalysts were investigated using various characterization techniques. Toluene's removal efficiency and CO 2 selectivity in the catalyst system were classified as follows: CuCeZr/T > MnCeZr/T > NiCeZr/T > CoCeZr/T > FeCeZr/T. Presence of water vapor exhibits an inhibitory effect on the conversion of toluene, which diminishes at higher temperatures. One contribution of this paper is to obtain the oxidation pathway of toluene and the relationship between the activation energy of all-inclusive and elementary reactions based on the variation of infrared spectrum using Freeman-Carroll method. Another contribution is to clarify the share of Langmuir-Hinshelwood and Mars-van Krevelen mechanisms during the oxidation of toluene over CuCeZr/T catalyst by transient response experiments of isotopically labeled oxygen. These findings provide a feasible method for the design and synthesis of transition metal oxide catalysts for industrial applications. [ABSTRACT FROM AUTHOR]