0
Research Papers

Solar Hydrogen Productivity of Ceria–Scandia Solid Solution Using Two-Step Water-Splitting Cycle

[+] Author and Article Information
Chong-il Lee

e-mail: lee.c.ab@m.titech.ac.jp

Qing-Long Meng

e-mail: meng.q.ab@m.titech.ac.jp

Hiroshi Kaneko

e-mail: kaneko.h.ac@m.titech.ac.jp

Yutaka Tamaura

e-mail: tamaura.y.aa@m.titech.ac.jp

Department of Chemistry,
Tokyo Institute of Technology,
Ookayama 2–12-1, Meguro-ku, Tokyo
152–8552, Japan

1Corresponding author.

Contributed by the Solar Energy Division of ASME for publication in the JOURNAL OF SOLAR ENERGY ENGINEERING. Manuscript received October 12, 2011; final manuscript received May 6, 2012; published online June 22, 2012. Assoc. Editor: Wojciech Lipinski.

J. Sol. Energy Eng 135(1), 011002 (Jun 22, 2012) (7 pages) Paper No: SOL-11-1221; doi: 10.1115/1.4006876 History: Received October 12, 2011; Revised May 06, 2012

The reactivity of CeO2–Sc2O3 solid solution for solar hydrogen production via two-step water-splitting reaction has been studied in this work. The CeO2–Sc2O3 solid solution was synthesized by polymerized complex method (PCM) with various Sc content between 0 and 20 mol. %. Analysis results from online direct gas mass spectrometry (DGMS) suggest that Ce3 + formed by CeO2–Sc2O3 solid solution in the O2-releasing step could be completely oxidized by H2O to generate hydrogen and return to Ce4 + in the H2-generation step. A Ce0.97Sc0.03O1.985 generates the largest amount of O2 and H2 among present samples, and the reduction and oxidation ratios are about 9.9% (Ce) and 10% (Ce), respectively. An estimated H2-generation reaction rate is about 4 ml g−1min−1 for Ce0.97Sc0.03O1.985. This value is about seven times greater than that of Ce0.89Zr0.11O2. The high reaction rate of Ce0.97Sc0.03O1.985 makes all formed Ce3 + completely oxidized by H2O in 5 min in the H2-generation step. The reasons for high performance are discussed from the views of lattice distortion and the amount of oxygen vacancies formed in the lattice.

FIGURES IN THIS ARTICLE
<>
Copyright © 2012 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

The phase diagram between Ce and O in the temperature range of (a) 200–1200 °C and (b) 1150–1350 °C. These diagrams are reported in previous study [11,12-11,12].

Grahic Jump Location
Fig. 2

Two-step water splitting experimental set-up

Grahic Jump Location
Fig. 3

Temperature and environmental gas conditions for the two-step water splitting

Grahic Jump Location
Fig. 4

XRD patterns: (A) overall view and (B) enlarged view of each sample. (a) CeO2, (b) Ce0.99Sc0.01O1.995, (c) Ce0.97Sc0.03O1.985, (d) Ce0.93Sc0.07O1.965, (e) Ce0.9Sc0.1O1.95, and (f) Ce0.8Sc0.2O1.9.

Grahic Jump Location
Fig. 5

Lattice constant versus Sc content in CeO2–Sc2O3 solid solution

Grahic Jump Location
Fig. 6

DGMS profiles of (a) Ce0.97Sc0.03O1.985 and (b) Ce0.9Zr0.1O2 (as an example) for two-step water splitting cycle and calibration

Grahic Jump Location
Fig. 7

SEM images of Ce0.97Sc0.03O1.985; (a) after synthesis and (b) after two-step water splitting cycles

Grahic Jump Location
Fig. 8

Reduction and oxidation ratio in each cycle of (a) CeO2 reduction, (b) CeO2oxidation, (c) Ce0.99Sc0.01O1.995 reduction, (d) Ce0.99Sc0.01O1.995 oxidation, (e) Ce0.97Sc0.03O1.985 reduction, (f) Ce0.97Sc0.03O1.985 oxidation, and (g) Ce0.93Sc0.07O1.965

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In