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Catalytic partial oxidation (CPOX) of n-butanol is an alternative route for hydrogen production from bio-mass. An analysis on the thermodynamics using Gibbs free energy minimization method was carried out, and the results indicated that a higher H2 yield can be obtained near 700 °C or above with O2/butanol = 1.5–2.0. Layered double hydroxide (LDH) derived catalysts were proved effective in CPOX, and the Ni0.35Mg2.65Al0.5Fe0.5O4.5±δ catalyst produced about 4.03 mol-H2/mol-butanol at 700 °C with a feed of O2/butanol = 2.0. This higher activity can be attributed to the structural and electronic properties: there is a higher surface area of 178.2 m2/g, and more Ni0 atoms were obtained and remained stable in the 31-h CPOX test. [ABSTRACT FROM AUTHOR]

Abstract: The manganese-promoted nickel-based catalysts were prepared via wet-incipient impregnation, and tested in auto-thermal reforming (ATR) of ethanol for hydrogen production. The Ni/Al2O3 catalyst, in which Ni existed as NiAl2O4, produced a low H2 yield near 1.85 mol H2/mol ethanol. The Ni–Mn/Al2O3 catalyst showed a better performance in a 30-h test: the conversion of ethanol reached 100%, and a higher H2 yield remained stable near 3.1–3.2 mol H2/mol ethanol. This improvement can be attributed to the promotion of Mn: With Mn, the ilmenite-type NiMnO3 was formed, the reducibility of Ni–Mn/Al2O3 was thus improved, and there were more Ni0 over the surface of catalysts. Moreover, these Ni0 species were stable in the ATR test, as indicated by XRD and XPS. [Copyright &y& Elsevier]

Abstract: Iron-doped LaNiO3 catalysts with a perovskite structure were prepared via self-combustion and tested in auto-thermal reforming (ATR) of ethanol. Characterizations of temperature-programmed surface reaction (TPSR), X-ray diffraction (XRD), physical N2 adsorption, and temperature-programmed reduction (TPR) were carried out. The results indicate that LaNiO3 perovskite structure was successfully formed via self-combustion. With iron-doping in LaNiO3, the perovskite structure still remains, in the form of solid solution La(Ni, Fe)O3, where iron is reducible and the nickel-iron alloy forms after the reduction. In addition, the surface area of the iron-doped samples increased. The TPSR results indicate that with iron-doping, the activity for adsorbed ethanol species is modified and a higher activity for methane transformation is achieved. As a result, an LNF10 sample (LaNi0.90Fe0.10O3) with both nickel and nickel-iron alloy shows better performance in ATR: the ethanol conversion is near 100%, while the selectivity to by-products, such as ethylene, ethane, acetaldehyde and methane, is decreased, and CO2 is the main carbon-containing product; consequently, a hydrogen yield near 3.0 mol H2/mol EtOH is obtained and remains stable in the 30-h test of ATR. [Copyright &y& Elsevier]

Abstract: Ni-based layered double hydroxide (LDH)-derived catalysts with Ni–Mg–Al–Fe–O were prepared via co-precipitation, and were tested in auto-thermal reforming (ATR) of ethanol for hydrogen production. The Ni0.35Mg2.65AlO4.5±δ catalyst showed poor stability and a low H2 yield, near 2.51mol H2/mol EtOH. The tetra-component catalyst of Ni0.35Mg2.65Al0.50Fe0.50O4.5±δ, in which the trivalent component consists of both aluminum and iron, showed a promising performance in ATR of ethanol: not only did the H2 yield remain stable near 3.7mol H2/mol EtOH during the 30-h test, but the CH4 reforming activity also improved and C2H4 disappeared in product gases. These improvements can be attributed to the synergic effect by both iron and nickel on the structural and electronic properties: the BET surface area was increased, the reducibility of the Ni metal and its resistance to oxidation in ATR were improved, and the acidity was constrained as well. [ABSTRACT FROM AUTHOR]

Abstract: Layered double hydroxide-derived Co0.3 Mg2.7Al1-xFexO4.5±δ catalysts were prepared via co-precipitation and tested in auto-thermal reforming of ethanol for hydrogen production. The layered double hydroxide precursors show typical hydrotalcite-like structures and form a similar MgO cubic structure after calcination. Compared with iron-free catalyst, the Co0.3 Mg2.7Al0.9Fe0.1O4.5±δ performs better in auto-thermal reforming of ethanol: the conversion of ethanol remains near 100%, and the H2 yield stays above 3.2mol H2/mol EtOH throughout the 30-h test. The improved performance can be attributed to the stable Cobalt species within Mg(Al)O matrix, the higher surface area, and the synergic effects of Co and Fe. [ABSTRACT FROM AUTHOR]

Abstract: Auto-thermal reforming (ATR) of bio-ethanol is a promising process for hydrogen production, which can lead to the possibility of directly using low concentration ethanol from fermentation plants without going through the energy-consuming distillation and dehydration processes, saving both energy and cost. Co-based catalysts are active for hydrogen production in ATR, where the hydrogen yield and stability are important factors to be considered. To address the concerns of selectivity and deactivation, iron was introduced into Co-based catalysts via wet-impregnation. The catalysts were characterized with TPR, XRD, XPS, and Raman spectra, and tested in ATR of ethanol. The XPS, XRD, and TPR results show that with iron-promotion, more Co metal is obtained over the catalyst surface, which remains stable during the oxidative atmosphere of ATR. Meanwhile, iron promotes the ethanol dehydrogenation pathway in ATR reactions. This synergic effect contributes to the higher activity and stability of Co-based catalysts in the ATR process: A higher hydrogen yield remains around 3.13mol H2/mol EtOH at 600°C and stays stable in a 30-h test. [Copyright &y& Elsevier]

Abstract: Nanorod alumina-supported Ni–Zr–Fe/Al2O3 catalysts were prepared by co-impregnation, characterized by TEM, TPR, XRD, XPS, and TPD-pyridine, and tested in auto-thermal reforming of ethanol. The characterization results indicate that, with iron and zirconia promotion, the Ni x Fe1−x Al2O4 mixture spinel forms, the valence of the surface Ni species is modified, and the acidity decreases. As a result, during a 30-h test over the Ni–Zr–Fe/Al2O3 catalyst, sintering is restrained, and the selectivity to hydrogen remains around 85.79% without obvious loss, while the un-promoted Ni/Al2O3 shows poor stability and selectivity. [Copyright &y& Elsevier]

Abstract: A series of iron-promoted nickel-based catalysts were prepared, and tested in auto-thermal reforming (ATR) of ethanol for hydrogen generation. With iron introduction, mixed crystals of NiAl2O4–FeAl2O4 spinel phase are formed, which results in modifications in reduction properties and surface electronic properties. The reaction results show a synergic effect of mixed crystals that significantly promotes the catalytic performance: over 10 wt.% iron loading nickel catalyst, conversion of ethanol at 98.43% and selectivity to hydrogen at 108.71% can be achieved at 600°C in ATR of ethanol, which is higher than that of the conventional Ni catalyst (i.e. by 47.44% on hydrogen selectivity). [Copyright &y& Elsevier]

Abstract: Iron-promoted nickel-based catalysts were prepared by impregnation, tested in auto-thermal reforming (ATR) of ethanol for hydrogen production, and characterized by TPR, XRD, BET, TEM, and XPS. With the introduction of iron, mixed crystals of NiAl2O4–FeAl2O4 spinel phase are formed, which results in modifications of its structural and electronic properties. The reaction results show a remarkable improvement on durability in catalytic activity as well as selectivity to hydrogen in ATR: over the 10wt.% iron-loading nickel catalyst, conversion of ethanol at 99.61% and selectivity of hydrogen around 115% are kept at 600°C during a 30-h test, while that of iron-free sample decreases sharply from 85.10% to 19.71% on hydrogen selectivity within a 26-h test. The improved durability is attributed to the synergistic effect of the NiAl2O4–FeAl2O4 mixed crystals that are more resistant to sintering and oxidation in the oxidative atmosphere of ATR. [Copyright &y& Elsevier]

The x%Ni/Sm2O3-MnO (x = 0, 10, 15, 20) catalysts derived from SmMn2O5 mullite were prepared by solution combustion and impregnation method; auto-thermal reforming (ATR) of acetic acid (HAc) for hydrogen production was used to explore the metal-support effect induced by Ni loadings on the catalytic reforming activity and product distribution. The 15%Ni/Sm2O3-MnO catalyst exhibited optimal catalytic performance, which can be due to the appropriate Ni loading inducing a strong metal–support interaction to form a stable Ni/Sm2O3-MnO active center, while side reactions, such as methanation and ketonization, were well suppressed. According to characterizations, Sm2O3-MnO mixed oxides derived from SmMn2O5 mullite were formed with oxygen vacancies; nevertheless, loading of Ni metal further promoted the formation of oxygen vacancies, thus enhancing adsorption and activation of oxygen-containing intermediate species and resulting in higher reactivity with HAc conversion near 100% and hydrogen yield at 2.62 mol-H2/mol-HAc. [ABSTRACT FROM AUTHOR]

Hydrogen, as a promising energy carrier, can be extracted from renewable biomass derived acetic acid (HAc). Ni-based catalysts supported on solid solution of Sm2−xPrxO3±δ were prepared using a coprecipitation method and evaluated in auto-thermal reforming (ATR) of HAc for hydrogen production. The results revealed that Pr species infiltrated the Sm2O3 lattice and formed a solid solution structure with oxygen vacancy defects, in which the redox process of Sm3+ + Pr3+ Sm2+ + Pr4+ enhanced oxygen mobility, facilitating gasification of the coking precursor and suppressing carbon deposition. DFT analysis also confirmed that Pr doping into the Sm2−xPrxO3±δ solid solution significantly lowered the energy barrier by 112 kJ mol−1 for formation of oxygen vacancies. Additionally, the interaction between Ni0 and Sm2−xPrxO3±δ effectively improved the dispersion of Ni0 metal particles, inhibiting sintering of Ni species. Consequently, the NSP10 catalyst (Ni0.80Sm1.72Pr0.24O3.74±δ) exhibited outstanding catalytic performance for hydrogen production: the conversion of HAc approached 100%, while the hydrogen yield remained stable at 2.75 mol-H2/mol-HAc. [ABSTRACT FROM AUTHOR]

To obtain high yields of hydrogen, a series of ZrxPr1–xOy‐supported cobalt catalysts were synthesized by the sol‐gel method and tested in autothermal reforming (ATR) of acetic acid (HAc) derived from bio‐oil. X‐ray diffraction, nitrogen physisorption, H2‐temperature‐programmed reduction, and thermogravimetric analysis were conducted to investigate the factors affecting the activities of the catalysts. Over the Co‐Zr‐Pr‐O catalyst, a ZrxPr1–xOy solid solution was formed after calcination; meanwhile, the active component of Co0 was highly dispersed over the solid solution after reduction in hydrogen for 1 h at 700 °C. As a result, stable reactivity was recorded in the ATR process of HAc: the hydrogen yield reached 2.58 molH2molHAc-1 with near 100 % HAc conversion, while better resistance to coking was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of Ni-Y-Ti-O catalysts were synthesized by sol–gel. • Y 2 Ti 2 O 7 pyrochlore structure was formed with addition of Y species. • There were intrinsic oxygen vacancies within Y 2 Ti 2 O 7 pyrochlore structure. • Y 2 Ti 2 O 7 pyrochlore enhanced resistance to carbon deposition and sintering. • High catalytic performance was found for H 2 production via ATR of acetic acid. Hydrogen, as a clean and efficient alternative energy source, can be extracted from acetic acid (HAc), a bio-oil derivative from pyrolysis of renewable biomass. A series of Ni-Y-Ti-O catalysts were synthesized by the Pechini method and applied in auto-thermal reforming (ATR) of HAc for hydrogen production. The N10YT (15 wt% NiO, 75 wt% TiO 2 and 10 wt% YO 1.5) catalyst with Y 2 Ti 2 O 7 pyrochlore structure presented high activity and stability with a HAc conversion rate at 100% and H 2 yield near 2.62 mol-H 2 /mol-HAc, showing application potential for hydrogen production. Characteristics suggested that the improved activity can be attributed to formation of Y 2 Ti 2 O 7 pyrochlore structure with intrinsic oxygen vacancies and interaction between Ni metal and support by means of (1) promoting of electron transfer from Y3+ to Ti4+ and Ni2+ species, (2) facilitating generation of oxygen vacancies and (3) restraining sintering of Ni0 and coking. [ABSTRACT FROM AUTHOR]

Autothermal reforming (ATR) of acetic acid (HOAc) is a promising and alternative route for hydrogen production from renewable resources, but catalyst deactivation caused by cobalt metal sintering and coking is a major concern in ATR. In this work, perovskite‐like catalysts of the formula SrxTi1–xCoO3±δ (x = 0, 0.2, 0.5, and 0.8) were prepared by evaporation‐induced self‐assembly and then evaluated in ATR for hydrogen production. The SrxTi1–xCoO3±δ catalysts exhibited high activity and stability as well as 100 % conversion of HOAc. Additionally, the Co particles with strong metal‐support interaction of SrTi(Co)O3 inhibited coking and agglomeration, and showed potential for hydrogen production by the ATR process. [ABSTRACT FROM AUTHOR]

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]

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 Ca 2.55 Ni 0.45 AlO 4.5 catalyst, active sites of Ni–CaO–Ca 12 Al 14 O 33 were formed, and interaction among Ni, CaO and Ca 12 Al 14 O 33 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 + CO 2 ↔CaCO 3 and CaCO 3 +*C↔CaO+2CO, for gasification of coking precursors. Hence, the Ca 2.55 Ni 0.45 AlO 4.5 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-H 2 /mol-HAc at a rate of 40.34 mmol-H 2 /s/g-catalyst. Over the Ni–CaO–Ca 12 Al 14 O 33 active sites, the acetic acid conversion rate was 100%, and the hydrogen yield remained stable near 2.75 mol-H 2 /mol-HAc at a rate of 40.34 mmol-H 2 /s/g-catalyst during auto-thermal reforming of acetic acid. Image 1 • Auto-thermal reforming of acetic acid was used for hydrogen production. • Ca–Al LDHs with hydrocalumite was synthesized via co-precipitation. • Active sites of Ni–CaO–Ca 12 Al 14 O 33 produced H 2 at 40.34 mmol-H 2 /s/g-catalyst. • Coking precursors were gasified with CaO within active sites. • Sintering and oxidation were constrained within Ni–CaO–Ca 12 Al 14 O 33. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-2W/SiO 2 presents a promising hydrogen yield of 2.8 mol-H 2 /mol-HAc in the ATR. • The strong interaction of WO 2 -Ni relieved carbon deposition and sintering of Ni0. • The effect of electron donor by WO 2 species preserved a stable proportion of Ni0. • CH 3 COOH tends to be enriched on the surface of WO 2 of the WO 2 /Ni(1 1 1) interface. Nickel-based catalysts exhibit excellent initial activity in the auto-thermal reforming (ATR) of acetic acid (HAc) to produce hydrogen; meanwhile, deactivation issues, namely oxidation, sintering and carbon deposition, have not been fully addressed. Hence, we prepared a series of Ni–W/SiO 2 catalysts and found the Ni-2W/SiO 2 catalyst with 2 wt% W decoration presented the best catalytic activity and stability: the conversion rate of acetic acid was stable at 100 %, and the hydrogen yield remained at 2.8 mol-H 2 /mol-HAc with neither sintering nor carbon deposition. The excellent catalytic performance of Ni-2W/SiO 2 was analyzed and can be attributed to the special properties of WO 2 as followed: First, during the ATR process, WO 2 species migrated to the surface of Ni phase and formed an interface, which resulted in strong interaction of WO 2 -Ni and relieved carbon deposition and sintering of Ni species; Second, the effect of electron donor by WO 2 species on the WO 2 -Ni interface during the reduction procedure was found and preserved a stable proportion of Ni0 active species during the ATR process; Third, DFT and in-situ DRIFTS confirmed that CH 3 COOH tends to be enriched on the WO 2 species of the WO 2 /Ni(1 1 1) interface rather than on the Ni(1 1 1) surface, promoting the adsorption and dehydrogenation of CH 3 COOH to intermediates of CH 3 COO* and H*, which is difficult to occur on WO 3 species of the WO 3 /Ni(1 1 1) interface because of high reaction barrier. [ABSTRACT FROM AUTHOR]

The well-dispersed Co species which partly incorporated into the lattice of CeO 2 (nanorod) was successfully synthesized, and a higher proportion of Ce3+/(Ce3+ + Ce4+) and enhanced oxygen mobility were thus obtained, which accounts for the high reactivity in auto-thermal reforming of acetic acid. [Display omitted] • Well-dispersed Co species partly doped into the lattice of CeO 2 (nanorod). • Enhanced oxygen mobility and higher Ce3+ was observed over Co-Ce-O (nanorod). • Co-Ce-O (nanorod) presents high hydrogen yield of 2.69 mol-H 2 /mol-HAc at 600 °C. As the preparation method was vital to modify the structure of catalysts, Co-Ce-O oxides were fabricated via different hydrothermal methods and evaluated in auto-thermal reforming (ATR) of acetic acid (HAc) for hydrogen production. Results of characterizations, including XRD, BET, H 2 -TPR, SEM and XPS, indicated the structure and electronic characteristics of each catalyst varied with different synthesis methods. In the case of CC-R with the morphology of nanorod, well-dispersed Co species were partly incorporated into the lattice of CeO 2 support, resulting in a higher proportion of Ce3+/(Ce3+ + Ce4+) and enhanced oxygen mobility. Consequently, it exhibited a promising catalytic performance in a 10-h testing in ATR of HAc: HAc conversion maintained at 96.8% with hydrogen yield recorded at 2.69 mol-H 2 /mol-HAc at 600 °C, while almost no by-product was detected, demonstrating its potential for hydrogen production. [ABSTRACT FROM AUTHOR]

Acetic acid (AC) is a representative compound of bio-oil via fast pyrolysis of biomass, and can be processed for hydrogen production via steam reforming (SR). In the current work, the Ni x Co 1− x Mg 6 O 7± δ ( x = 0–1) bimetallic catalysts were prepared via co-precipitation and impregnation, and tested in SR of AC. The reaction results indicate that the monometallic catalysts were deactivated obviously in SR, while the Ni 0.2 Co 0.8 Mg 6 O 7± δ bimetallic catalyst performed better in both activity and stability: not only the conversion of AC remained stable near 100%, but also the H 2 yield maintained stable near 3.1 mol-H 2 /mol-AC. The results of XRD, BET, XPS, TG and TEM indicate that the high catalytic performance of the Ni 0.2 Co 0.8 Mg 6 O 7± δ catalyst can be attributed to 1) resistance to oxidation of active metals, 2) resistance to coking, and 3) stability of structure and electronic properties. [ABSTRACT FROM AUTHOR]

Abstract: Ni-Mg-Mn-Fe-O catalysts were prepared via co-precipitation through layered double hydroxide (LDH) precursors and tested for hydrogen production from ethanol by auto-thermal reforming (ATR). With Mn and Fe in the precursor of the Ni0.35 Mg2.65Mn0.5Fe0.5O4.5±δ catalyst, an LDH structure formed via co-precipitation, and after calcination, a cubic MgO skeleton formed with spinel phases of NiMn2O4 and NiFe2O4. The H2 yield reached 4.0mol-H2/mol-EtOH and remained stable in a 30-h ATR test, which can be attributed to the improvement of reduction behavior and stability of Ni0 species. [Copyright &y& Elsevier]

• NiY x Zr 0.85-x O y catalysts with Y-Zr-O solid solution were prepared by EISA. • NiY 0.2 Zr 0.65 O 1.75 exhibits high hydrogen yield of 3.0 mol-H 2 /mol-HAc in ATR of HAc. • Strong interaction between Ni and Y-Zr-O support inhibited sintering. • High oxygen mobility provided by Y-Zr-O promoted the gasification of C* species. Auto-thermal reforming (ATR) is an effective route to extract hydrogen from both water and acetic acid (HAc) from bio-oil. With addition of oxygen into ATR, the reaction heat can be balanced, but the migration of oxygen for oxidation of carbonous species from HAc is still a concern. Here, we report NiY x Zr 0.85-x O y (x = 0, 0.05, 0.1, 0.2, 0.4, 0.85) catalysts with Y-Zr-O solid solution as support for hydrogen production via ATR of HAc. The oxygen vacancies provided by Y-Zr-O solid solution are beneficial to activating surface oxygen species and improve oxygen mobility of the nickel catalyst, thus the oxygen transfer from reactant to product CO and CO 2 was enhanced. On the other hand, Ni nanoparticles, the active metal, are highly dispersed on the Y-Zr-O solid solution carrier. Consequently, the NiY 0.2 Zr 0.65 O 1.75 catalyst exhibits the highest activity and enhanced stability: the acetic acid conversion is near 100 % and the yield of hydrogen reaches 3.0 mol-H 2 /mol-HAc, and no obviously coking is found after the reaction. [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]