On the microwave enhanced combustion synthesis of CuO–ZnO–Al 2 O 3 nanocatalyst used in methanol steam reforming for fuel cell grade hydrogen production: Effect of microwave irradiation and fuel ratio Hossein Ajamein, Mohammad Haghighi ⇑ Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz, Iran Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz, Iran article info Article history: Received 29 January 2016 Received in revised form 31 March 2016 Accepted 1 April 2016 Keywords: CuO–ZnO–Al 2 O 3 Microwave combustion Methanol steam reforming Hydrogen abstract CuO–ZnO–Al 2 O 3 nanocatalysts were synthesized by the microwave-assisted solution combustion method to produce hydrogen via the steam methanol reforming reaction. The influence of fuel/nitrates ratio and microwave irradiation was investigated. For this purpose, a series of CuO–ZnO–Al 2 O 3 nanocatalysts were fabricated using different amounts of ethylene glycol as fuel in a microwave oven and a conventional furnace. The characteristic properties of prepared nanocatalysts were studied by X-ray diffraction, field emission electron microscope, specific surface area, energy dispersive X-ray and Fourier transform infra- red spectroscopy analyses. The crystallography and morphology studies clarified that application of microwave oven instead of conventional furnace led to higher crystallinity of CuO and ZnO species and homogeneously smaller particles, respectively. Therefore, the surface area of sample synthesized in the microwave oven was higher than the other prepared in the furnace. The enhancement of fuel/nitrates ratio also increased specific surface area and dispersion of different species. Thus, with regards to signif- icant physicochemical properties of the sample fabricated by the microwave assisted combustion method with fuel/nitrates ratio = 3, the catalytic experiments showed that it facilitated the methanol conversion even at low temperatures and its hydrogen and CO selectivity did not change severely during 1200 min under reaction conditions. Ó 2016 Elsevier Ltd. All rights reserved. 1. Introduction The reduction of fossil fuels reserves and international aware- ness of environmental pollution concerns become reasons for find- ing alternative fuels especially for vehicles. Among different candidates, hydrogen is known as a promising energy carrier for future by virtue of the fact that it can be produced from various sources including renewable ones [1–3]. The recent attractive tech- nology which proposed for replacing conventional internal com- bustion engines is fuel cells. Fuel cell powered systems consume pure hydrogen to generate the energy needed for vehicles without emission of environmental pollutants [4,5]. Due to safety problems of hydrogen storage in vehicles, most of the researches focused on on-board hydrogen generation. Among various alternatives such as glycerol [6,7], dimethyl ether [8], ethanol [9] as well as even animal waste [10], methanol is an attractive choice because of its several advantages such as high H/C ratio, lower sulfur content, no C–C bonding, and commercially large scale production from differ- ent sources [11,12]. The steam methanol reforming process is well known as highly efficient route for production of hydrogen from methanol. It is a surface catalytic reaction which mostly takes place on copper or 8–10 group of transition metals based catalysts. Between these two, copper based catalysts are frequently used because of their high activity and hydrogen selectivity [13–15]. Although the CuO–ZnO–Al 2 O 3 is known as a commercial catalyst of the steam methanol reforming (SMR) process but its application in on- board fuel cells for vehicles has some limitations. For this case, it is expected that the catalyst has a high methanol conversion with high hydrogen yield and producing low concentration of CO as the undesired byproduct [16,17]. Various solutions have been proposed to overcome these obstacles such as applying effective promoters and synthesis methods [18–20]. The synthesis method can play a critical role on performance of catalysts in the SMR reac- tion. Historically, co-precipitation and impregnation are known as the conventional routes for fabrication of catalysts. Therefore, it is expectable that the majority of works have been taken place on http://dx.doi.org/10.1016/j.enconman.2016.04.002 0196-8904/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: Reactor and Catalysis Research Center, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz, Iran. E-mail address: haghighi@sut.ac.ir (M. Haghighi). URL: http://rcrc.sut.ac.ir (M. Haghighi). Energy Conversion and Management 118 (2016) 231–242 Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman