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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]

Auto-thermal reforming (ATR) of acetic acid (HAc) offers a feasible, carbon-neutral way to produce hydrogen, and Ni-based catalysts were found effective in ATR, while catalytic deactivation by sintering and carbon deposition needs to be addressed. Therefore, novel Mn-doped NiTiO3 catalysts were prepared by evaporation induced self-assembly method and tested in ATR; characterizations were used to explore the internal catalytic relationship between the carrier and active metals. The experimental results indicated the NiTiO3 catalyst doped with 10 wt.% of MnO exhibited the highest activity and enhanced stability: the conversion of HAc was stable at 100% and the yield of hydrogen was recorded near 2.5 mol-H2/mol-HAc. The characterization results showed that the NiTiO3 catalyst presented the highest specific surface area at 7.5 m2/g. After reduction and activation, NiTiO3 was transformed into Ni0, while Mn replaced Ni in NiTiO3 and formed a stable phase of MnTiO3 perovskite, which presented confinement effect on Ni0, preventing migration of Ni0 at high temperature with a relatively stable particle size within 41.6-44.5nm. These MnTiO3-supported nickel species effectively promoted the conversion of intermediate products such as CH3CO*, inhibited carbon deposition and improved hydrogen selectivity, showing application potential for hydrogen production via ATR of HAc. [ABSTRACT FROM AUTHOR]

Nickel-based catalysts are widely applied in auto-thermal reforming (ATR) of acetic acid (HAc) to extract hydrogen, but the persistent issue of coking is still a concern. Herein, Ce 1-x Y x O 2-δ solid solutions were obtained to support nickel and the catalytic activity for the ATR was examined. The results indicated that with Y species in CeO 2 lattice, the Ce 1-x Y x O 2-δ solid solution structures with lattice defects and cell dislocation were formed; Meanwhile, the strong nickel-support interaction effectively constrained aggregation of Ni0; In addition, the solid solution induced formation of oxygen vacancies, and facilitated transfer and activation of oxygen species (O*). The DFT analysis further evidences the lower formation energy of oxygen vacancy over the solid solution. Therefore, the optimized Ni 0.8 Ce 1.76 Y 0.35 O 4.85 ±δ catalyst provided excellent stability for activity test (50 h), in which HAc conversion and H 2 yield stabilized at 100% and 2.6 mol-H 2 /mol-HAc, respectively, without obvious coking. [Display omitted] • Solid solution Ce 1-x Y x O 2-δ nickel-based catalysts were synthesized by sol-gel. • Lattice defects and cell dislocation were caused by Y atom insertion. • Y doping enhanced resistance to carbon deposition of nickel-based catalyst. • Ni 0.8 Ce 1.76 Y 0.35 O 4.85 ±δ catalyst shows better performance for ATR of acetic acid. • DFT shows that Y doping decreases the formation energy of oxygen vacancy. [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]

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]

[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]

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]

• 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]