Understanding the positive effects of (Co-Pi) co-catalyst modification in inverse-opal structured α-Fe2O3-based photoelectrochemical cells

Xinjian Shi, Kan Zhang, Jong Hyeok Park

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42 Citations (Scopus)


Recent studies found that Co-Pi as a co-catalyst is of great significance for water oxidation in photoelectrochemical (PEC) cell because it efficiently suppresses surface electron/hole recombination. Besides, it leads to a cathodic shift for the onset potential obviously. In this study, the synergic effect between inverse-opal structured α-Fe2O3 and cobalt-phosphate (Co-Pi) component is investigated. As expected, the photocurrent density of the novel Co-Pi/α-Fe2O3 photoanode shows a significant enhancement compared to that of bare inverse-opal structured α-Fe2O3 especially at low potential, which can be ascribed to the efficient charge separation by the introduction of Co-Pi and 3D nanostructure. Not only that, a dramatic decrease in dark current is also noticed after being Co-Pi modification. To explain this phenomenon, a mechanism study has been carried out by using a series of joint characterizations, including I/V curve feature, Mott-Schottky plot and impedance analysis. The results reveal that the Co-Pi modification in 3D α-Fe 2O3 structure can also facilitate electron transport in skeleton structure. These findings make 3D nanostructure-based PEC with Co-Pi co-catalyst modification a more promising approach to generate hydrogen/oxygen from water splitting.

Original languageEnglish
Pages (from-to)12725-12732
Number of pages8
JournalInternational Journal of Hydrogen Energy
Issue number29
Publication statusPublished - 2013 Sep 30

Bibliographical note

Funding Information:
This research was supported by NRF grant funded by the Korea Government (MEST) ( NRF-2013R1A2A1A09014038 , 2011-0030254 , NRF-2009-C1AAA001-2009-0094157 ).

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology


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