Photoelectrochemical and electrocatalytic properties of thermally oxidized copper oxide for efficient solar fuel production

Angel T. Garcia-Esparza, Kevin Limkrailassiri, Frederic Leroy, Shahid Rasul, Weili Yu, Liwei Lin, Kazuhiro Takanabe*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)


We report the use of a facile and highly scalable synthesis process to control growth products of earth-abundant Cu-based oxides and their application in relevant photoelectrochemical and electrochemical solar fuel generation systems. Characterization of the synthesized Cu(I)/Cu(II) oxides indicates that their surface morphology and chemical composition can be simply tuned by varying two synthesis parameters (time and temperature). UV-Vis spectroscopy and impedance spectroscopy studies are performed to estimate the band structures and electronic properties of these p-type semiconductor materials. Photoelectrodes made of Cu oxides possess favorable energy band structures for production of hydrogen from water; the position of their conduction band is ≈1 V more negative than the water-reduction potential. High acceptor concentrations on the order of 1018-1019 cm-3 are obtained, producing large electric fields at the semiconductor-electrolyte interface and thereby enhancing charge separation. The highly crystalline pristine samples used as photocathodes in photoelectrochemical cells exhibit high photocurrents under AM 1.5G simulated illumination. When the samples are electrochemically reduced under galvanostatic conditions, the co-existence of the oxide with metallic Cu on the surface seems to function as an effective catalyst for the selective electrochemical reduction of CO2.

Original languageEnglish
Pages (from-to)7389-7401
Number of pages13
JournalJournal of Materials Chemistry A
Issue number20
Early online date5 Mar 2014
Publication statusPublished - 28 May 2014
Externally publishedYes


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