Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance work on Wednesday 27th March 2019 from 11:00 AM to 1:00 PM (GMT).

During this time our website performance may be temporarily affected. We apologise for any inconvenience this might cause and thank you for your patience.


Issue 11, 2019
Previous Article Next Article

Sr- and Co-doped LaGaO3−δ with high O2 and H2 yields in solar thermochemical water splitting

Author affiliations

Abstract

Solar thermochemical CO2/H2O splitting cycles based on redox oxides have emerged as a potential strategy to store dilute and intermittent solar energy. It is desirable to explore other materials that can convert solar energy into chemical energy with high efficiency. Herein, a thermochemical water splitting (TCWS) cycle based on Sr- and Co-doped LaGaO3−δ (La1−xSrxGa1−yCoyO3−δ) was successfully developed. Compared with inert LaGaO3−δ, the oxygen vacancy concentration (δ) is gradually increased as the contents of Sr- and/or Co-dopants increased. The δ value of LaGa0.4Co0.6O3−δ (LGC60) reaches 0.16 after reduction for 40 min at 1350 °C, which is 5 and 4 times that of Ce0.85Zr0.15O2−δ and LSMA6464, respectively. The H2 yield of LGC60 (478 μmol H2 g−1perovskite) is 15 times that of the current state-of-the-art material, CeO2−δ (32 μmol H2 g−1material), when reduced at 1350 °C and re-oxidized at optimized 800 or 1000 °C. 1.0 atom% IrOx as a catalyst doped into the structure of LGC50, named LGC50-Ir(1.0), can increase the H2 release rate by 1.3-fold. XPS results reveal that the H2O splitting reaction is driven by the Co2+/Co3+ redox pair. DFT calculations predict that the oxygen vacancy formation energies (EV) of La1−xSrxGa1−yCoyO3 span from nearly 0.7 to about 5.3 eV under vacuum conditions at 1623 K, depending on the contents of Sr- and Co-dopants. Thus, doping Co at the B-site is responsible for the introduction of redox activity, and adjusting Sr- and Co-contents is effective in tuning the δ and EV values of La1−xSrxGa1−yCoyO3−δ. It should be pointed out that, at present, the steam to hydrogen conversion ratios for LaGa1−yCoyO3−δ under the used evaluation conditions are still very low (<1%) and far away from the practical demand, which is a common tradeoff in this field, and more attention should be paid in future material screening work. This discovery provides a useful strategy to design perovskite oxides with enhanced TCWS activity and it will promote the development of solar thermochemical fuel conversion science.

Graphical abstract: Sr- and Co-doped LaGaO3−δ with high O2 and H2 yields in solar thermochemical water splitting

Back to tab navigation

Supplementary files

Publication details

The article was received on 11 Dec 2018, accepted on 31 Jan 2019 and first published on 14 Feb 2019


Article type: Paper
DOI: 10.1039/C8TA11957K
Citation: J. Mater. Chem. A, 2019,7, 6099-6112

  •   Request permissions

    Sr- and Co-doped LaGaO3−δ with high O2 and H2 yields in solar thermochemical water splitting

    Z. Chen, Q. Jiang, F. Cheng, J. Tong, M. Yang, Z. Jiang and C. Li, J. Mater. Chem. A, 2019, 7, 6099
    DOI: 10.1039/C8TA11957K

Search articles by author

Spotlight

Advertisements