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Iron-promoted nickel-based catalysts for hydrogen generation via auto-thermal reforming of ethanol
Lihong Huang a, Jian Xie a, Wei Chu a, Rongrong Chen a, Deryn Chu c, Andrew T. Hsu a,b,*
Lugar Center for Renewable Energy,Indiana University – Purdue University, Indianapolis, Indianapolis, IN 46202-5160, USA Purdue School of Engineering and Technology, Indiana University – Purdue University, Indianapolis, 799 West Michigan Street, ET 215, Indianapolis, IN 46202-5160, USA c US Army Research Laboratory, Adelphi, Maryland, MD 20783, USA
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A series of iron-promotednickel-based catalysts were prepared, and tested in auto-thermal reforming (ATR) of ethanol for hydrogen generation. With iron introduction, mixed crystals of NiAl2O4–FeAl2O4 spinel phase are formed, which results in modiﬁcations in reduction properties and surface electronic properties. The reaction results show a synergic effect of mixed crystals that signiﬁcantly promotes the catalytic performance:over 10 wt.% iron loading nickel catalyst, conversion of ethanol at 98.43% and selectivity to hydrogen at 108.71% can be achieved at 600 °C in ATR of ethanol, which is higher than that of the conventional Ni catalyst (i.e. by 47.44% on hydrogen selectivity). Ó 2008 Elsevier B.V. All rights reserved.
Article history: Received 20 June 2008 Received in revised form 18 October 2008 Accepted 22October 2008 Available online 29 October 2008 Keywords: Hydrogen generation Nickel catalyst Iron promoter Auto-thermal reforming Ethanol
1. Introduction Hydrogen is considered as a promising candidate as the energy carrier of the future as it can be obtained from renewable sources (like water or biomass) through thermal or catalytic processes, utilizing a diverse set of domestic resources. The useof renewable hydrogen will reduce the energy dependence on fossil fuels, cut greenhouse gas emissions and provide for a sustainable energy supply [1–3]. In the past, some attention has been devoted to investigating processes for the production of hydrogen from bioethanol through catalytic steam reforming (SR), which can be coupled with fuel cells applications. Several problems still exist thatlimit the applications of SR, including the strong endothermicity of the overall process and the difﬁculties to develop longterm stable and coke resistant catalysts [4,5]. The auto-thermal reforming (ATR) of ethanol appears to be an attractive alternative process whose features include a reduced rate of carbon deposition and a more favorable heat equilibrium, which can be designed as a function of theoxygen gas in feed [4,6].
* Corresponding author. Address: Purdue School of Engineering and Technology, Indiana University – Purdue University, Indianapolis, 799 West Michigan Street, ET 215, Indianapolis, IN 46202-5160, USA. Tel.: +1 317 274 2533; fax: +1 317 274 4567. E-mail address: email@example.com (A.T. Hsu). 1566-7367/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.doi:10.1016/j.catcom.2008.10.018
A high yield of hydrogen can be achieved using noble metalbased catalysts such as Rh/Al2O3 in ATR, but the high cost of noble metals limits its practical applications [1,7]. As a non-precious-metal catalyst, nickel-based catalyst is also a promising candidate in ATR of ethanol. However, one of the major problems in the application of Ni catalyst is the low hydrogenyield at low temperatures. Additionally, the catalyst deactivation caused by sintering and carbon deposition on the catalyst surface is another concern for ATR. Therefore, many studies have been carried out to improve the activity and stability of Ni catalysts by using additional metals such as Cu, Mo, and Co or using different supports such as CeO2, La2O3 and Y2O3 [8–12]. Iron has been used as an...