Reproducible performance of a Ni/La2O3–αAl2O3 catalyst in ethanol steam reforming under reaction–regeneration cycles

•Ni/La2O3–αAl2O3 has been studied in reaction–regeneration cycles for ethanol steam reforming.•Reproducible behavior requires equilibration of the catalyst (reaction at 700 °C and regeneration at 550 °C with air).•The equilibrated catalyst has lower activity than the untreated one due to partial Ni sintering.•The equilibrated catalyst has lower Ni content on the surface and requires lower reduction temperature.

Equilibration of a Ni/La2O3–αAl2O3 catalyst has been studied with the aim of using it in ethanol steam reforming (ESR) under reaction–regeneration cycles. The runs have been performed in a fluidized bed reactor, with the reaction steps being carried out at 500 °C and 700 °C, with a steam/ethanol (S/E) molar ratio of 6 and low values of space time (from 0.001 to 0.06 gcatalysth/gEtOH), for which there is fast deactivation by coke formation. The catalyst is regenerated between steps in the reactor itself by coke combustion with air at 550 °C for 2 h. Reproducible performance of the catalyst in the successive reaction–regeneration cycles requires a severe equilibration treatment consisting in a reaction–regeneration cycle, with the reaction step at 700 °C. Several analytical techniques (XRD, H2 chemisorption, TPR, and XPS) allowed proving that the catalyst undergoes partial Ni sintering in the equilibration treatment, which explains its lower activity compared to the non-equilibrated catalyst.