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Abstract In this study, the cobalt-cerium spinel oxides catalysts were prepared via a citric acid complex method. The catalytic performance and physicochemical properties of the samples for deep propane oxidation were evaluated. Co 2 Ce 1 O x catalysts exhibit the superior low temperature activity with a T 50 value of 220 °C, which is much lower than both individual cobalt and cerium oxides. The results show that cerium ions could enter into the spinel-type lattice of the cobalt oxides and lead to the severe lattice distortion. The activated Co O bonds favor the propane activation and enhance the reducibility of active Co3+ species. Meanwhile, high proportion of Co3+ content and better oxygen mobility are also observed in the cobalt-cerium spinel oxides catalysts. The kinetic and the transient experiments reveal that the reduction step of the catalysts plays a crucial role in the deep catalytic propane oxidation. The reaction rate of Co 2 Ce 1 O x catalyst reaches 0.22 μmol g−1 s−1 at 200 °C and its activation energy is the lowest (57.9 kJ mol−1). All the results indicate that the combination of redox behaviors of Co 3 O 4 and oxygen vacancies of CeO 2 offer useful support for catalysts design toward propane oxidation at low temperature. Graphical abstract Unlabelled Image Highlights • Catalytic propane oxidation was performed over cobalt-cerium spinel oxides catalysts. • Co 2 Ce 1 O x showed the highest low temperature activity. • Reduction step of the catalysts is crucial for catalytic propane oxidation. • Proportion of Co3+ is linear with the reaction rates at 200 °C. [ABSTRACT FROM AUTHOR]

Abstract In recent years, significant effort has been made in the development of novel catalysts for the total oxidation of chlorinated volatile organic compounds. In this work the catalytic activity of Cu doped cerium-titanium binary oxides for the oxidation of dichloromethane (DCM) have been studied for the first time. Combining catalysts characterization and activity data, it was found that Cu ions can uniformly disperse into titanium dioxide to form solid solution and induce the creation of additional surface oxygen species on the catalysts surface, while moderate amount of Ce ions are still needed for the activation of C Cl. Detailed analysis of the in-situ FTIR experiment results revealed that the surface oxygen species, especially the hydroxyl groups associated with Cu ions, can promote the deep oxidation of the intermediate species formed in the nucleophilic substitution process occurred on the active sites of catalysts surface. The sample with the Cu/Ce molar ratio of 1:3 obtained a better CO 2 selectivity than that reached with cerium-titanium binary oxides. Meanwhile, according to element balance analysis, removal of chlorine from the catalyst surface was also promoted by Cu doping. Graphical abstract Image 1 Highlights • Catalytic oxidation of dichloromethane over Ce, Cu, Ti ternary oxides has been studied. • Cu doping can promote the products selectivity to CO2 and enhance Cl balance. • Correlation between catalyst structure and catalytic behavior is revealed. • Promotion Mechanism of Cu doping for dichloromethane deep oxidation was explored. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel catalysts for CVOCs removal present excellent low-temperature activity and high chlorine resistance. • WO x loading affects the surface species morphology while polymer structure at 10% loading shows the best performance. • The RuO 2 -WO x /Sn 0.2 Ti 0.8 O 2 catalysts exhibit highly stable activity in both dry and wet conditions. • Experimental and computational results prove WO 2 Cl 2 to be the main species for tungsten loss on chlorine poisoned catalysts. • The removal performance of CB, TCE and DCM by the cordierite catalyst is validated. The development of catalysts with high activity, selectivity, and durability is crucial for the catalytic oxidation of chlorinated volatile organic compounds (CVOCs). Although acid-modified supports are widely used in catalysis to improve the catalytic activity at low temperature, the acid sites are easily deactivated by Cl poisoning, and the poisoning mechanism remains unclear. Here, a series of RuO 2 -WO x /Sn 0.2 Ti 0.8 O 2 catalysts were synthesized for dichloromethane (DCM) catalytic oxidation. Spectroscopic characterizations revealed that the loading amount of tungsten oxide highly affects the structure of the surface species and, consequently, the low-temperature catalytic activity. SEM, XRD and DFT calculations elucidated that the loss of tungsten species in the form of WO 2 Cl 2 is the main reason for the catalyst deactivation. By loading RuO 2 , the loss of tungsten species could be effectively avoided via the Deacon reaction. The cordierite catalyst exhibits excellent catalytic activity for the oxidation of different types of CVOCs. [ABSTRACT FROM AUTHOR]

• Developed a new RuO 2 -WO 3 /Sn 0.2 Ti 0.8 O 2 catalyst formula for CVOCs catalytic removal. • Studied the effect of RuO 2 loading on catalyst's acidity and catalytic performance. • Studied the synergistic catalysis of CVOCs and multiple pollutant components. Chlorine-containing volatile organic compounds emitted from combustion boilers and chemical industries will cause great harm to the ecological environment and human health. Catalytic combustion technology is one of the commonly used technologies for the treatment of CVOCs. Poor low-temperature activity, high levels of toxic by-products, and poor resistance to chlorine poisoning are common problems faced by its catalyst development. In order to effectively remove CVOCs, we constructed a RuO 2 -WO 3 / Sn 0.2 Ti 0.8 O 2 catalyst formula in which RuO 2 and WO 3 were supported on Sn 0.2 Ti 0.8 O 2 , and tested with DCM as a model molecule. By detecting the catalytic performance of RuO 2 -WO 3 /Sn 0.2 Ti 0.8 O 2 series catalysts with different RuO 2 loadings on DCM and corresponding characterization methods, we found that 3 wt%RuO 2 -5 wt%WO 3 /Sn 0.2 Ti 0.8 O 2 catalyst had the best catalytic performance (T 90% value was 291 °C, CO 2 selectivity was close to 100% at 325 °C). The actual industrial environment often contains multiple gas pollutants at the same time, so it is important to study the ability of the catalyst to co-process multiple pollutants. The effects of other pollutants (propane, acetone, SO 2 and NO 2) in the reaction atmosphere on the catalytic oxidation performance of DCM were further studied. It was found that the RuO 2 -WO 3 /Sn 0.2 Ti 0.8 O 2 catalyst could achieve the coordinated removal of acetone, propane and dichloromethane, and the effects of SO 2 and NO 2 on catalytic oxidation performance of DCM was revealed. It is hoped that it can serve as a reference and guidance for the subsequent industrial application of the catalyst in this system. [ABSTRACT FROM AUTHOR]