Steam reforming of toluene over perovskite-supported Ni catalysts

Authors:  Yasushi Sekine, Daiki Mukai, Yuki Murai, Satoshi Tochiya, Yoshiyuki Izutsu, Kei Sekiguchi, Naomi Hosomura, Hirohisa Arai, Eiichi Kikuchi, Yukihiro Sugiura

Abstract:
Hydrogen production by steam reforming of toluene as a model aromatic hydrocarbon has been investigated with various Ni/perovskite catalysts. Among them, Ni/LaAlO₃ catalyst showed high catalytic activity. Partial substitution of the La site of LaAlO₃ support with other elements (Sr, Ba or Ca) was conducted for the Ni/LaAlO₃ catalyst, and substitution with 30% Sr promoted catalytic activity and selectivity to hydrogen. Optimization for the Ni loading amount over Ni/La_0.7Sr_0.3AlO_3−ı catalyst revealed that 5 wt% Ni/La_0.7Sr_0.3AlO₃−ı had the highest toluene conversion and the smallest amount of carbon deposition. To elucidate the role of doped Sr, the catalytic natures of Sr-substituted catalyst Ni/La_0.7Sr_0.3AlO_3−ı and Srsupported catalyst Ni/Sr/LaAlO3 were compared. Results show that Sr-ions should be incorporated in the LaAlO3 perovskite structure to show high catalytic performance. Based on results of transient response test with H₂¹⁸O on Ni/La_0.7Sr_0.3AlO₃−ı, Ni/Sr/LaAlO₃, and Ni/LaAlO₃ at reaction temperature of 873K, the formation of 18O-products was observed only on Ni/La_0.7Sr_0.3AlO_3−ı catalyst derived from redox between the lattice oxygen in the perovskite and water. Lattice oxygen in the La_0.7Sr_0.3AlO_3−ı support worked as active oxygen species to enhance its catalytic nature.

Keywords:
Steam reforming
Hydrogen production
Perovskite oxide
Lattice oxygen
Coke-formation

Published in: Applied catalysis A: General  (Volume 451, Pages 1-288, 31 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Steam reforming of toluene over perovskite-supported Ni catalysts

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