Durable Mn(II)Cr(III)Ox composites-supported Ni-based catalysts with wide dynamic range for hydrogen production via auto-thermal reforming of acetic acid.

• Precursors of spinel AB 2 O 4 phase (A = Mn(II), B = Mn(III) or Cr(III)) were formed. • Ni/Mn(II)Cr(III)O x±δ with MnO as skeleton and highly dispersed Cr species obtained. • Stable activity in static and dynamic conditions via ATR of acetic acid was obtained. • H 2 yield with 367.4 mmol-H 2 /(g cat ·h) and 100% conversion recorded in a 50-h ATR test. • Resistance to coking, sintering and oxidation was observed in NiMn3.84Cr1.61O8.53 ± δ. Acetic acid (HAc) from biomass oil is a promising hydrogen storage material that can be used for the supply of hydrogen to on-board fuel cells, while durable catalysts are a vital factor for reliable hydrogen feeding. Mn(II)Cr(III)O x composites-supported Ni-based catalysts (Ni/Mn(II)Cr(III)O x±δ) were prepared via co-precipitation method, and tested in auto-thermal reforming (ATR) of HAc for hydrogen production. Different process parameters, including reaction temperatures, O 2 /HAc molar ratios and gas hourly space velocity (GHSV), were studied in both static and dynamic conditions. The NiMn 3.84 Cr 1.61 O 8.53±δ catalyst exhibited excellent catalytic activity and stability in a 50-h ATR test: the HAc conversion reached 100%, and the hydrogen yield remained stable near 3.0 mol-H 2 /mol-HAc with a rate of 367.4 mmol-H 2 /(g cat ·h); meanwhile, the reactivity maintained stable with GHSV up to 45000 ml/(g cat ·h) in both static and stop-restart tests, in which neither carbon deposition nor sintering was found, showing potential for hydrogen production with fast response in on-board application. This improved reactivity can be due to: 1) composites of spinel AB 2 O 4 phase (A = Mn(II), B = Mn(III) or Cr(III)) after calcination, 2) stable Mn(II)Cr(III)O x composites, in which MnO existed as skeleton with highly dispersed Cr species in multi-layered structures after reduction treatment, 3) efficient activation of O 2 /H 2 O by active sites of Ni/Mn(II)Cr(III)O x±δ , facilitating oxygen transfer and gasification of coking. [ABSTRACT FROM AUTHOR]