Ethanol steam reforming for renewable hydrogen production over La-Modified TiO2 catalyst

Abstract

In recent years, ethanol steam reforming (ESR) has received considerable attention as a promising route for cleaner H2 production. This process could be industrially advantageous, ideally yielding 6 moles of H2 per mole of ethanol reacted. The major drawbacks of the process are the endothermic nature of the reaction and presence of CO2 in the product. At low temperatures (below 500 °C), side reactions that yield alternative products such as acetic acid, acetaldehyde and ethylene are favoured. Besides promoting ESR, higher temperatures make the process costly for an industrial development while promoting CO, CO2 and coke formation, which is the main cause of catalyst deactivation. In this study, a series of La-loaded TiO2 catalysts were prepared by an impregnation-co-precipitation method, La being a well-known inhibitor of CO and CO2 formation. Catalytic ethanol steam reforming was conducted in a tubular fixed bed reactor operated at 1 atm, 500 °C and an ethanol/water molar feed ratio of 10:1. The influence of La-loading on inhibiting coke formation and selectivity towards hydrogen formation by ethanol steam reforming has been investigated. The catalytic performance of La-loaded TiO2 catalyst was found to be considerably higher when compared to the pure TiO2. At 10 % La loading, ethanol conversion of ~27.5 % was achieved with a H2 mole fraction of 0.53. Significant amounts of valuable products such as CH4 and C2H4 were also detected in the product mixture. More importantly, CO was not detected over La-loaded TiO2 catalyst, which confirmed its ability for minimizing coke formation. This development has confirmed improved efficiency of La/TiO2 catalyst toward renewable hydrogen production.