Dolomite-derived Ni-based catalysts with Fe modification for hydrogen production via auto-thermal reforming of acetic acid

Abstract

Bio-oil can be obtained via fast pyrolysis of biomass, and typically contains acetic acid (~30 mass %). The acetic acid has often been tested as a model compound for hydrogen production via reforming bio-oil, in which catalysts are a key factor for stable hydrogen production. However, deactivation of catalysts by coking and oxidation hinders the application of the reforming process. Dolomite-derived Ni-based catalysts with Fe additive, MgNi0.2Ca0.8−xFexO2±δ (x = 0–0.8), were successfully synthesized by the hydrothermal synthesis method, and then tested in auto-thermal reforming (ATR) of acetic acid (AC). The MgNi0.2Ca0.5Fe0.3O2±δ catalyst performed a stable reactivity in ATR: the conversion of AC reached 100%, and the H2 yield remained stable around 2.6 mol-H2/mol-AC. The catalysts were characterized by X-ray diffraction (XRD), N2 physisorption, X-ray photoelectron spectra (XPS), H2-temperature-programmed reduction (TPR), inductively coupled plasma- atomic emission spectroscopy (ICP-AES) and Thermogravimetry (TG); the results show that a periclase-like solid solution of Mg(Ni,Fe)O and lime were formed via the precursors of dolomite and hydrotalcite, and then transformed into Fe-rich Ni-Fe alloy with basic support of MgO-CaO after reduction. The stable Ni0 spices with basic support can explain the stability and resistance to coking during ATR of AC.