Hydrogen production from ethanol by steam reforming with recyclable NiCaOx/NaCl catalysts

Abstract

In this paper, a recyclable and reprocessed NiCaO_x/NaCl catalyst using the hydrothermal method was developed to produce hydrogen from ethanol steam reforming, aiming to tackle the high expenses of commercial reforming catalysts and the challenges of recycling after failure and disposal. Findings indicated that NiCaO_x/NaCl catalysts efficiently generated hydrogen from ethanol. The optimized 1%-NiCaO_x/NaCl catalyst achieved approximately 100% hydrogen yield, complete ethanol conversion at 650–700 °C, and sustained operation at 650 °C for 50 hours following oxygen treatment. The regenerated catalyst was restored to the original state of the fresh sample. Thorough characterization analysis confirmed that the NiCaO_x/NaCl catalyst with an ultra-small specific surface area overcame the limitation of achieving high catalytic activity for catalysts with a small specific area. The induction effect of the NaCl support on NiO effectively enhanced the low-temperature redox performance of the catalyst. NaCl itself efficiently adsorbed ethanol molecules with an adsorption energy of −0.56 eV per molecule. The addition of CaO improved the adsorption of ethanol molecules with an adsorption energy of −0.73 eV per molecule. Consequently, the NiCaO_x/NaCl catalyst rapidly adsorbed and activated ethanol molecules, and generated surface hydroxyl groups to facilitate the oxidation of ethanol to acetaldehyde and acetic acid, subsequently releasing H₂ and CO₂.