Hydrogen Production via Methane Decomposition Using Ni and Ni-Cu Catalysts Supported on MgO, Al 2 O 3 and MgAl 2 O 4
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Hydrogen Production via Methane Decomposition Using Ni and Ni-Cu Catalysts Supported on MgO, Al2O3 and MgAl2O4 José F. Pola1, Miguel A. Valenzuela2*, Iván A. Córdova2 and J. A. Wang2 1 Centro de Investigación en Materiales Avanzados, Miguel de Cervantes 120, 31109, Chihuahua, Chih., Mexico 2 Lab. Catálisis y Materiales. ESIQIE-Instituto Politécnico Nacional. Zacatenco, 07738, México D.F., Mexico. Email: [email protected] ABSTRACT Ni (10%) and Ni-Cu (50 and 25%, respectively) catalysts supported on alumina, magnesia and magnesium aluminate were synthesized. The characterization was carried out by X-ray diffraction, nitrogen physisorption, temperature programmed-reduction, Raman spectroscopy and SEM. The catalysts were tested in the methane decomposition reaction using a tubular fixed bed reactor operated in the range of 500-580°C under atmospheric pressure. A higher activity was observed with the bimetallic catalysts supported on alumina and magnesium aluminate. These results were explained in terms of Ni-Cu alloy formation and weak metalsupport interaction. In the case of monometallic catalysts, a strong metal-support interaction was detected, which revealed the lowest activity and stability compared with the bimetallic catalysts. The formed carbon was a combination of amorphous and graphite. INTRODUCTION A transition to a new energy economy instead of the dominant hydrocarbon economy will be an unavoidable issue in this century due to a finite amount of available fossil fuels and to the disastrous consequences of released carbon dioxide to the atmosphere. The need to ensure safety of energy supply to move towards the use of sustainable local energy resources, to reduce global carbon dioxide emissions, and to create a new industrial and technological energy base will be the main drivers for the transition [1, 2]. Many publications have been devoted to the study of a hydrogen economy to replace fossil fuels for transportation, electricity for distribution through the grid and to provide portable electricity for personal electronics and other applications [3-5]. Hydrogen is currently produced via steam reforming (SR) of natural gas or light hydrocarbons. This is a mature technology, however, is not an attractive production route for the future hydrogen economy, because the increasing demand of hydrogen would deplete our finite reserves and would have a high pollution with produced COx (CO and CO2) [6,7]. Although, improvements to the traditional SR processes and to other small scale existing technologies have been done in the last decade [8], there are a number of other potential pathways to produce hydrogen: methane decomposition [9], selective oxidation of methane [10], SR with membrane reactors [11], solar-assisted SR [12], solar energy for electrolysis of water [12], photocatalysis [13], electrolysis of water using fuel cells [14], biomass conversion [15], and biological hydrogen production [16], among others. The catalytic decomposition of methane (CDM) can be used to obtain COx-free hydrogen and has become an inte
