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Biomass-derived acetic acid (HAc), as a hydrogen storage medium, can be transformed to hydrogen via on-board reformer for fuel cells. Steam reforming (SR) of HAc is a traditional hydrogen production process, but endothermicity of SR is a concern for heat management in dynamic on-board application. Auto-thermal reforming (ATR) of HAc is a promising route, while catalyst deactivation in harsh ATR atmosphere should be addressed. Samarium-promoted ordered mesoporous Ni-xSm-Al-O catalysts were synthesized via improved evaporation-induced self-assembly (EISA) method, and tested in ATR of HAc for hydrogen production. The Ni-2Sm-Al-O catalyst produced a stable HAc conversion near 100.0% and a hydrogen yield at 2.6 mol-H 2 /mol-HAc in a 30-h test. Meanwhile, the Ni-2Sm-Al-O catalyst shows resistance to oxidation, sintering and coking; this improved reactivity and durability can be attributed to basic Sm oxides and ordered mesoporous framework with confinement effect: the basic sites are beneficial to adsorption and activation of HAc, and the ordered mesoporous framework constrains the thermal agglutination of Ni metal and formation of coking, while intermediate carbonous species of *CH x (x = 0–3) can be gasified via the Sm 2 O 3 -Sm 2 O 2 CO 3 cycle. These Sm-promoted Ni-based catalysts are also tested with different temperatures and O/C, and show potentials in ATR of HAc for hydrogen production. Image 1 • Stable hydrogen production by auto-thermal reforming of acetic acid was achieved. • Conversion of CH 3 COOH at 100.0% and H 2 yield at 2.6 mol-H 2 /mol-HAc were obtained. • Ordered mesoporous Ni-xSm-Al-O synthesized by evaporation induced self-assembly. • Sm enhanced specific surface area and alkalinity of the Ni-xSm-Al-O catalysts. • Confinement effect by mesopores restrained coking and sintering of Ni0 species. [ABSTRACT FROM AUTHOR]

• 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]