Effect of combining Al, Mg, Ce or La oxides to extracted rice husk nanosilica on the catalytic performance of NiO during COx-free hydrogen production via methane decomposition. (13th April 2017)

• Record Type: Journal Article
• Authors: Awadallah, Ahmed E.; Solyman, Sanaa M.; Aboul-Enein, Ateyya A.; Ahmed, Hanan A.; Aboul-Gheit, Noha A.K.; Hassan, Salah A.
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 15(2017)
• Page Start: 9858
• Page End: 9872
• Publication Date: 2017-04-13
• Subjects: Rice husk silica -- Hydrogen production -- Methane decomposition -- Catalyst supports -- Carbon nanomaterials; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.03.049
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Amorphous nanosilica powder was extracted from rice husk and used as a catalyst support as well as a starting material for the preparation of different binary oxides, i.e., SiO2 Al2 O3, SiO2 MgO, SiO2 CeO2 and SiO2 La2 O3 . A series of supported nickel catalysts with the metal loading of 50 wt % were prepared by wet impregnation method and evaluated in methane decomposition to "COx -free" hydrogen production. The fresh and spent catalysts were extensively characterized by different techniques. Among the evaluated catalysts, both Ni/SiO2 Al2 O3 and Ni/SiO2 La2 O3 catalysts were the most active with an over-all H2 yield of ca. 80% at the initial period of the reaction. This distinguishable higher catalytic activity is mainly referred to the presence of free mobile surface NiO and/or that NiO fraction weakly interacted with the support easily reducible at low temperatures. The Ni/SiO2 CeO2 catalyst has proven a great potential for application in the hydrogen production in terms of its catalytic stability. The formation of Mgx Ni(1−x) O solid solution caused the Ni/SiO2 MgO catalyst to lose its activity and stability at a long reaction time. Various types of carbon materials were formed on the catalyst surface depending on the type of support used. TEM images of as-deposited carbon showed that multi-walled carbon nanotubes (MWCNTs) and graphene platelets were formed on Ni/SiO2, while only MWCNTs were deposited on all binary oxide supported Ni catalysts. Highlights: Highly pure amorphous nanosilica was successively synthesized from rice husk. Effect of Al, Mg, La or Ce oxides addition to silica on the activity of Ni was studied. Hydrogen production via methane decomposition was studied over Ni-based catalysts. Various types of deposited carbon were obtained depending on the support nature.