Reduction reactivity of CeO2–ZrO2 oxide under high O2 partial pressure in two-step water splitting process

Kaneko, Hiroshi; Taku, S.; Tamaura, Yutaka

doi:10.1016/j.solener.2011.06.019

Cited by 70 publications

(46 citation statements)

References 42 publications

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“…These results are in good agreement with results found in the literature [45,46]. Further increasing the Zr content diminishes the reducibility of the material to X red/ox ≈ 10%.…”

Section: Splitting Performance Depending On Thesupporting

confidence: 92%

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Thermogravimetric Analysis of Zirconia-Doped Ceria for Thermochemical Production of Solar Fuel

Call¹,

Roeb²,

Schmücker³

et al. 2013

AJAC

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Developing an efficient redox material is crucial for thermochemical cycles that produce solar fuels (e.g. H 2 and CO), enabling a sustainable energy supply. In this study, zirconia-doped cerium oxide (Ce 1−x Zr x O 2 ) was tested in CO 2 -splitting cycles for the production of CO. The impact of the Zr-content on the splitting performance was investigated within the range 0 ≤ x < 0.4. The materials were synthesized via a citrate nitrate auto combustion route and subjected to thermogravimetric experiments. The results indicate that there is an optimal zirconium content, x = 0.15, improving the specific CO 2 -splitting performance by 50% compared to pure ceria. Significantly enhanced performance is observed for 0.15 ≤ x ≤ 0.225. Outside this range, the performance decreases to values of pure ceria. These results agree with theoretical studies attributing the improvements to lattice modification. Introducing Zr 4+ into the fluorite structure of ceria compensates for the expansion of the crystal lattice caused by the reduction of Ce 4+ to Ce 3+ . Regarding the reaction conditions, the most efficient composition Ce 0.85 Zr 0.15 O 2 enhances the required conditions by a temperature of 60 K or one order of magnitude of the partial pressure of oxygen p(O 2 ) compared to pure ceria. The optimal composition was tested in long-term experiments of one hundred cycles, which revealed declining splitting kinetics.

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“…These results are in good agreement with results found in the literature [45,46]. Further increasing the Zr content diminishes the reducibility of the material to X red/ox ≈ 10%.…”

Section: Splitting Performance Depending On Thesupporting

confidence: 92%

“…The results clearly indicate that the substitution of Ce 4+ by isovalent Zr 4+ enhances the reducibility, w ith earlier studies [40,[46][47][48]. For some authors, the enhancement is attributed to modifications in the crystal structure.…”

Section: Splitting Performance Depending On Thesupporting

confidence: 79%

Thermogravimetric Analysis of Zirconia-Doped Ceria for Thermochemical Production of Solar Fuel

Call¹,

Roeb²,

Schmücker³

et al. 2013

AJAC

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show abstract

“…[1][2][3][4][5][6][7] The reaction scheme, as written out explicitly for the case of H 2 production from H 2 …”

Section: Introductionmentioning

confidence: 99%

High-temperature isothermal chemical cycling for solar-driven fuel production

Hao

Yang

Haile

2013

Phys. Chem. Chem. Phys.

126

129

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The possibility of producing chemical fuel (hydrogen) from the solar-thermal energy input using an isothermal cycling strategy is explored. The canonical thermochemical reactive oxide, ceria, is reduced under high temperature and inert sweep gas, and in the second step oxidized by H 2 O at the same temperature. The process takes advantage of the oxygen chemical potential difference between the inert sweep gas and high-temperature steam, the latter becoming more oxidizing with increasing temperature as a result of thermolysis. The isothermal operation relieves the need to achieve high solidstate heat recovery for high system efficiency, as is required in a conventional two-temperature process.Thermodynamic analysis underscores the importance of gas-phase heat recovery in the isothermal approach and suggests that attractive efficiencies may be practically achievable on the system level.However, with ceria as the reactive oxide, the isothermal approach is not viable at temperatures much below 1400 1C irrespective of heat recovery. Experimental investigations show that an isothermal cycle performed at 1500 1C can yield fuel at a rate of B9.2 ml g À1 h À1 , while providing exceptional system simplification relative to two-temperature cycling.

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“…Ce 0.5 Zr 0.5 O 2 support was prepared by polymerizable complex method [44,63]. Aqueous solutions of cerium nitrate Ce(NO) 3 • 6H 2 O and zirconium oxychloride ZrOCl 2 • 8H 2 O taken in the equimolar ratio were added to the solution of citric acid (CA) in ethylene glycol (EG) at 70 °C.…”

Section: Support and Catalyst Preparationmentioning

confidence: 99%

Application of POSS Nanotechnology for Preparation of Efficient Ni Catalysts for Hydrogen Production

Исмагилов

Матус

Kuznetsov

et al. 2017

Eurasian Chem. Tech. J.

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POSS (polyhedral oligomeric silsesquioxanes) nanotechnology was applied for preparation of efficient Ni catalysts for hydrogen production through autothermal reforming of methane (ATR of CH 4 ). The novel metal-POSS precursor [Nickel (II) -HeptaisobutylPOSS (C 4 H 9 ) 7 Si 7 O 9 (OH)O 2 Ni] of Ni nanoparticles was introduced into Ce 0.5 Zr 0.5 O 2 support with following calcination and reduction stages of activation. The peculiarity of the genesis of Ni/SiO 2 /Ce 0.5 Zr 0.5 O 2 nanomaterials and their characteristics versus deposition mode were studied by X-ray fluorescence spectroscopy, thermal analysis, N 2 adsorption, X-ray diffraction, high-resolution transmission electron microscopy and H 2 temperature-programmed reduction. The two kinds of supported Ni-containing particles were observed: highly dispersed Ni forms (1-2 nm) and large Ni-containing particles (up to 50-100 nm in size). It was demonstrated that the textural, structural, red-ox and, consequently, catalytic properties of ex-Ni-POSS catalysts depend on the deposition mode. The increase of a portion of difficultly reduced Ni 2+ species is found upon application of intermediate calcination during Ni-POSS deposition that has detrimental effect on the activity of catalyst in ATR of CH 4 . The Ni/SiO 2 /Ce 0.5 Zr 0.5 O 2 catalyst prepared by one-step Ni-POSS deposition exhibits the highest H 2 yield -80% at T = 800 °C.

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Reduction reactivity of CeO2–ZrO2 oxide under high O2 partial pressure in two-step water splitting process

Cited by 70 publications

References 42 publications

Thermogravimetric Analysis of Zirconia-Doped Ceria for Thermochemical Production of Solar Fuel

Thermogravimetric Analysis of Zirconia-Doped Ceria for Thermochemical Production of Solar Fuel

High-temperature isothermal chemical cycling for solar-driven fuel production

Application of POSS Nanotechnology for Preparation of Efficient Ni Catalysts for Hydrogen Production

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