Hydrogen production by aqueous-phase reforming of ethylene glycol over a Ni/Zn/Al derived hydrotalcite catalyst

Abstract

Ni/Zn/Al hydrotalcites (Ni/Zn/Al-HT) with different Ni/Zn ratios have been prepared by a coprecipitation method. The properties and microstructure of Ni/Zn/Al-HT precursors and derived catalysts were characterized by X-ray diffraction (XRD), H₂-temperature programmed reduction (TPR), N₂ physical adsorption analysis (BET), scanning electron microscopy (SEM) and particle size distribution. The results exhibited that the as-prepared samples consisted of a hydrotalcite phase and a ZnO phase, and Zn²⁺ was introduced into the layers. At the ratio of Ni/Zn = 1, the ZnAl₂O₄ phase emerged after calcination; Ni still remained in its original state after reaction, and ZnO always existed during the whole process. In aqueous-phase reforming (APR) of ethylene glycol, the H₂ production rate over Ni/Zn/Al-HT was high, and the selectivity of H₂ can almost reach 100% with a high conversion rate exceeding 99%.