Mayenite supported perovskite monoliths for catalytic combustion of methyl methacrylate

To improve their thermal stability, La0.8Sr0.2MnO3 cordierite monoliths are washcoated with mayenite, which is a novel Al-based material with the crystal structure of 12MO 7Al2O3 （M= Ca, Sr）. The monoliths are characterized by means of nitrogen adsorp- tion/desorption, scanning electron microscopy, and X-ray diffraction. Catalytic performances of the monoliths are tested for methyl methacrylate combustion. The results show that mayenite obviously improves both the physic- chemical properties and the catalytic performance of the monoliths. Because mayenite improves the dispersity of Lao.sSro.2MnO3 and also prevents the interaction between La0.8Sr0.2MnO3 and cordierite or γ-A1203, both crystal structure and surface morphology of La0.8Sr0.2MnO3 phase can thereby be stable on the mayenite surface even at high temperature up to 1050 ℃. Under the given reaction conditions, La0.8Sr0.2MnO3 monolith washcoated with 12SrO. γ-A1203 shows the best catalytic activity for methyl methacrylate combustion among all the tested monoliths.

Catalytic steam methane reforming enhanced by CO_2 capture on CaO based bi-functional compounds

Sorption enhanced steam methane reforming（SE-SMR） was performed to maximize hydrogen production and contemporary remove COfrom the product stream using bi-functional sorbent-catalyst compounds.Samples were tested at two different scales: micro and laboratory. The CaO amount varied in the CaO-CaAlOsorbent system synthesized by wet mixing(CaO content of 100 wt%, 56 wt%, 30 wt%, or 0 wt% and balance of CaAlO) which were upgraded to bi-functional compounds by impregnation of 3 wt% of Ni. Nitrogen adsorption（BET/BJH）, X-Ray Diffraction（XRD）, Temperature-Programmed Reduction（TPR） and Scanning and Transmission Electronic Microscopy（SEM and TEM, respectively） analyses were performed to characterize structural and textural properties and reducibility of the bi-functional materials and evaluate their catalytic behavior. A fixed sorbent composition CaO-CaAlO(56 wt% of CaO and CaAlObalance), was chosen to study the effect of different weight hourly space times（WHST） and CHstream compositions in SE-SMR activity. Impregnated mayenite at both micro and laboratory scales showed stable Hcontent of almost 74%, with CHconversion of 72% similarly to the values reported by the sample containing 30 wt% of CaO in the post-breakthrough.Sample with 30 wt% of CaO showed promisingly behavior, enhancing Hcontent up to almost 94.5%.When the sorption enhanced reaction is performed roughly 89% of CHconversion is achieved, and after the pre-breakthrough, the catalyst worked at the thermodynamic level. During cycling sorption/regeneration experiments, even if COremoval efficiency slightly decreases, CHconversion and Hyield remain stable.