Ca–Al layered double hydroxides-derived Ni-based catalysts for hydrogen production via auto-thermal reforming of acetic acid

Abstract

Biomass-derived acetic acid (HAc) is an alternative resource for hydrogen production, and heat self-sustained auto-thermal reforming (ATR) of HAc shows potential for practical application, while robust and stable catalysts remain as a key factor. Ca–Al layered double hydroxides (LDHs)-derived Ni-based catalysts were synthesized by co-precipitation, and tested in ATR of HAc for hydrogen production. Over the LDHs-derived Ca2.55Ni0.45AlO4.5 catalyst, active sites of Ni–CaO–Ca12Al14O33 were formed, and interaction among Ni, CaO and Ca12Al14O33 was proved to be a pivotal role for 1) thermal stability, 2) resistance to oxidation of Ni0 species, and 3) inhibiting coke deposition through catalytic cycle, CaO + CO2↔CaCO3 and CaCO3+*C↔CaO+2CO, for gasification of coking precursors. Hence, the Ca2.55Ni0.45AlO4.5 catalyst showed enhanced activity with no obvious deactivation in ATR: the acetic acid conversion rate was 100%, and the hydrogen yield remained stable near 2.75 mol-H2/mol-HAc at a rate of 40.34 mmol-H2/s/g-catalyst.