Calcination/acid-activation treatment of an anodic oxidation TiO_2/Ti film catalyst

The aim of this work was to investigate the effects of calcination/acid-activation on the composition, structure, and photocatalytic （PC） reduction property of an anodic oxidation TiO2/Ti film catalyst. The surface morphology and phase composition were examined by scanning electron microscopy and X-ray diffraction. The catalytic property of the film catalysts was evaluated through the removal rate of potassium chromate during the PC reduction process. The results showed that the film catalysts were composed of anatase and rutile TiO2 with a micro-porous surface structure. The calcination treatment increased the content of TiO2 in the film, changed the relative ratio of anatase and rutile TiO2, and decreased the size of the micro pores of the film catalysts. The removal rate of potassium chromate was related to the technique parameters of calcination/acid-activation treatment. When the anodic oxidation TiO2/Ti film catalyst was calcined at 873 K for 30 min and then acid-activated in the concentrated H2SO4 for 60 min, it presented the highest catalytic property, with the removal rate of potassium chromate of 96.3% during the PC reduction process under the experimental conditions.

An efficient and innovative catalytic reactor for VOCs emission control

Efficient mixing and thermal control are important in the flow reactor for obtaining a high product yield and selectivity.Here,we report a heterogeneous chemical kinetic study of propene oxidation within a newly designed catalytic jet-stirred reactor(CJSR).To better understand the interplay between the catalytic performances and properties,the CuO thin films have been characterized and the adsorbed energies of propene on the adsorbed and lattice oxygen were calculated using density functional theory(DFT)method.Structure and morphology analyses revealed a monoclinic structure with nano-crystallite size and porous microstructure,which is responsible for holding an important quantity of adsorbed oxygen.The residence time inside the flow CJSR(1.12–7.84 s)makes it suitable for kinetic study and gives guidance for scale-up.The kinetic study revealed that using CJSR the reaction rate increases with O_2concentration that is commonly not achievable for catalytic flow tube reactor,whereas the reaction rate tends to increase slightly above 30%of O_2due to the catalyst surface saturation.Moreover,DFT calculations demonstrated that adsorbed oxygen is the most involved oxygen,and it has found that the pathway of producing propene oxide makes the reaction of C_3H_6over CuO surface more likely to proceed.Accordingly,these findings revealed that CJSR combined with theoretical calculation is suitable for kinetic study,which can pave the way to investigate the kinetic study of other exhaust gases.