ΔΗΜΟΣΙΕΥΣΗ - SUSTAINABLE ENERGY AND FUELS

Title:    Ce-Sm-xCu cost efficient catalysts for H2 production through the glycerol steam reforming reaction [view paper]

 

Journal: Sustainable Energy and Fuels 3 (2019) 673-691.

 

Authors: Kyriaki Polychronopoulou,*ab Nikolaos D. Charisiou,c Georgios I. Siakavelas,c Ayesha A. AlKhoori,a Victor Sebastian,de Steven J. Hinderf, Mark A. Bakerf, Maria A. Goula*c

 

Affiliations:

aDepartment of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, UAE.

bCenter of Catalysis and Separation, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, UAE.

cLaboratory of Alternative Fuels and Environmental Catalysis (LAFEC), Department of Environmental and Pollution Control Engineering, Western Macedonia University of Applied Sciences, GR-50100, Greece.

dChemical and Environmental Engineering Department & Nanoscience Institute of Aragon (INA), University of Zaragoza, SP-50018, Zaragoza, Spain.

eNetworking Research Center on Bioengineering, Biomaterials and Nanomedicine, CIBER-BBN, 28029-Madrid, Spain.

fThe Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 4DL, UK.

 

Abstract

A series of Ce-Sm-xCu, (x=5, 7, 10 at.%) catalysts were prepared using coupling of microwave radiation with sol-gel method and were evaluated for the glycerol steam reforming reaction in the 400-750oC temperature range. Some critical comparison with co-precipitation catalysts is also discussed. The catalysts were characterized using BET, Raman, XRD, NH3-TPD, CO2-TPD, H2-TPR, SEM,HAADF-STEM and XPS, whereas the catalysts precursor compounds bonding environment and thermal stability were studied using FTIR and TGA/DSC. For all catalysts it was found that the Ce, Sm, and Cu cations are all homogeneously distributed into the cubic fluorite cell with interplanar spacing of 0.355 nm, 0.370 nm and 0.373 nm for the Ce-Sm-5Cu, Ce-Sm-7Cu and Ce-Sm-10Cu catalysts, respectively. The surface of the catalysts was found to be Ce- and Cu-poor and Sm-rich, with Ce4+, Ce3+, Sm3+, Cu2+ and Cu+ oxidation states identified. In the bulk, the oxygen vacancies were found to be dependent on the catalyst composition (Cu content). Among the catalysts studied, the Ce-Sm-5Cu one exhibits the highest selectivity for hydrogen (H2) with its SH2 ranging from 40% (400oC) to 75% (750oC). The Ce-Sm-5Cu catalyst also produces the highest amount of CO (97-71%) and the lowest amount of CO2 (3-28%) between all samples for the low reaction temperature range (400oC<T<600oC). For all catalysts, the CO/CO2 molar ratio is quite low (<7.0) for the whole temperature range, while the H2/CO molar ratio value remain almost stable (~2.0) for 400oC<T<600oC; it increases sharply for T>650oC and reaches the values of 7, 10 and 12 for the samples Ce-Sm-5Cu, Ce-Sm-7Cu, Ce-Sm-10Cu, respectively.