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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]

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]

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: 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]

[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]

• 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]