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3226339 
Journal Article 
A comparison of H2S, SO2, and COS poisoning on Ni/YSZ and Ni/K2O-CaAl2O4 during methane steam and dry reforming 
Jablonski, WS; Villano, SM; Dean, AM 
2015 
1 
Applied Catalysis A: General
ISSN: 0926-860X
EISSN: 1873-3875 
Elsevier 
502 
Elsevier 
399-409 
WOS:000361162200046 
A systematic comparison of sulfur poisoning on Ni/YSZ and Ni/K2O-CaAl2O4, a commercially available reforming catalyst, demonstrated the heightened and rapid degradation of Ni/YSZ methane reforming activity. Ni/K2O-CaAl2O4 has nearly 15 times the hydrogen uptake capacity of Ni/YSZ which implies a difference in active nickel area. Because of this difference in active nickel surface area, Ni/K2O-CaAl2O4 was diluted in pure alpha-Al2O3 to achieve the same active nickel surface area as Ni/YSZ. The turnover frequencies (TOF) for steam methane reforming without sulfur on Ni/YSZ and Ni/K2O-CaAl2O4 were similar, although there was some deactivation on Ni/K2O-CaAl2O4 possibly as a result of coking which was observed visually. Sulfur deactivation on both catalysts was examined for H2S, SO2, and COS at concentrations of 1, 3, and 5 ppm. Ni/YSZ deactivated rapidly to an activity close to zero. Ni/K2O-CaAl2O4 deactivated quickly in the first 20 min, but then reached a non-zero steady state activity. The relative deactivation rates for the sulfur species examined were COS > SO2 >= H2S. Reaction temperatures of 650 degrees C, 750 degrees C, and 800 degrees C were evaluated, but temperature did not strongly affect deactivation rates for either catalyst. The overarching result of this study is that Ni/YSZ methane reforming activity is more sensitive to sulfur deactivation than a commercial reforming catalyst. The effect is so strong, that the use of Ni/YSZ with any hydrocarbon fuel may require removal of sulfur to sub-ppm levels. (C) 2015 Elsevier B.V. All rights reserved. 
Methane steam reforming; Methane dry reforming; CO2 reforming; Hydrogen sulfide; Sulfur dioxide; Ni/YSZ; Solid oxide fuel cell; SOFC; Nickel catalyst; YSZ support; Sulfur poisoning; Carbonyl sulfide; Sulfur; Poisoning