Enhanced catalytic performance of Ni/α-Al2O3 catalyst modified with CaZrO3 nanoparticles in steam-methane reforming. (23rd November 2017)

• Record Type: Journal Article
• Authors: Lertwittayanon, Kowit; Youravong, Wirote; Lau, Woei Jye
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 47(2017)
• Page Start: 28254
• Page End: 28265
• Publication Date: 2017-11-23
• Subjects: H2 production -- Steam-methane reforming -- Ni catalyst -- CaZrO3 -- Perovskite oxide -- Oxygen vacancy; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.09.030
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Ni/α-Al2 O3 catalysts containing CaZrO3 nanoparticles as a promoter were prepared by sequential impregnation for H2 production from steam-methane reforming. The effects of different loadings of CaZrO3 nanoparticles from 0 to 15 wt% on the catalytic performance of Ni/α-Al2 O3 catalysts in steam-methane reforming were studied. The Ni/α-Al2 O3 catalysts containing 15 wt% CaZrO3 nanoparticles provided the highest H2 yield due to facilitative steps of enormous steam adsorption-dissociation at the sites of oxygen vacancies on the surface of CaZrO3 nanoparticles. The existence of facilitative steps created additional H + and OH − enhancing both H2 yield and the gasification of deposited carbon, respectively. The tests of steam-methane reforming at low S/C ratio of 1/3 for 97 h revealed that the catalytic performance of CaZrO3 -modified Ni/α-Al2 O3 catalysts was higher than that of the unmodified Ni/α-Al2 O3 catalyst. Interestingly, at high S/C ratio of 3 excessive steam adsorption at the oxygen vacancies on CaZrO3 nanoparticles resulted in highly competitive adsorption between steam and methane decreasing CH4 dissociation. The results suggested that in the steam-methane reforming, optimum S/C ratios for the CaZrO3 -modified Ni/α-Al2 O3 catalysts were relatively lower than those for the unmodified Ni/α-Al2 O3 catalyst due to excellent steam adsorption-dissociation capability for CaZrO3 nanoparticles. Graphical abstract: Highlights: Ni/α-Al2 O3 catalyst is modified by CaZrO3 for improving steam-methane reforming. Optimum CaZrO3 amounts in the Ni catalyst considerably promote H2 yield. CaZrO3 -modified Ni catalyst is effectively utilized especially at low S/C ratios. Oxygen vacancies in CaZrO3 play a key role in catalytic activity and stability. The added CaZrO3 nanoparticles function as both structural and chemical promoter.