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.
Bibliographical noteFunding 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