Hydrogen production by steam reforming of DME over Ni-based catalysts modified with vanadium

Abstract

Dimethyl ether steam reforming (DME-SR) for hydrogen production has been studied over VNi/Al2O3 catalysts as part of an investigation aimed at the development of effective technology based on second generation of biofuels. Methanol steam reforming (MeOH-SR) was investigated as a step of the DME-SR process. High activity in the MeOH-SR was observed and two different mechanism depending on temperature and influenced by the vanadium content (0.5, 1 and 3%) was evidenced: direct methanol decomposition to CO and H2 was observed at low temperature and low vanadium content and methanol steam reforming reaction occurs majorly to give an almost stoichiometric H2/CO2 ratio at moderate to high temperature (400 °C) over 3VNi. DME conversion is complete at 500 °C over VNi catalysts in DME-SR, as a two steps reaction: DME hydrolysis and MeOH-SR giving an H2 rich gas reformate generated with a H2 selectivity c.a. 60–70% over 0.5VNi and 3VNi, values maintained during 4.5 h of activity in the same reaction conditions with no signs of deactivation or significant coke formation over catalyst surface.