Universität zu Köln

Kaouk, A., Ruoko, T. -P., Gonullu, Y., Kaunisto, K., Mettenborger, A., Gurevich, E., Lemmetyinen, H., Ostendorf, A. and Mathur, S. (2015). Graphene-intercalated Fe2O3/TiO2 heterojunctions for efficient photoelectrolysis of water. RSC Adv., 5 (123). S. 101401 - 101408. CAMBRIDGE: ROYAL SOC CHEMISTRY. ISSN 2046-2069

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Abstract

Interfacial modification of alpha-Fe2O3/TiO2 multilayer photoanodes by intercalating few-layer graphene (FLG) was found to improve water splitting efficiency due to superior transport properties, when compared to individual iron and titanium oxides and heterojunctions thereof. Both metal oxides and graphene sheets were grown by plasma-enhanced chemical vapor deposition. Compared to the onset potential achieved for alpha-Fe2O3 films (1 V vs. RHE), the alpha-Fe2O3/TiO2 bilayer structure yielded a better onset potential (0.3 V vs. RHE). Heterojunctioned bilayers exhibited a higher photocurrent density (0.32 mA cm(-2) at 1.23 V vs. RHE) than the single alpha-Fe2O3 layer (0.22 mA cm(-2) at 1.23 V vs. RHE), indicating more efficient light harvesting and higher concentration of photogenerated charge carriers. For more efficient charge transport at the interface, a few layer graphene sheet was intercalated into the alpha-Fe2O3/TiO2 interface, which substantially increased the photocurrent density to 0.85 mA cm(-2) (1.23 V vs. RHE) and shifted the onset potential (0.25 V vs. RHE). Ultrafast transient absorption spectroscopy studies indicated that the incorporation of FLG between the alpha-Fe2O3 and TiO2 layers resulted in reduced recombination in the alpha-Fe2O3 layer. The results showed that graphene intercalation improved the charge separation and the photocurrent density of the FTO/alpha-Fe2O3/FLG/TiO2 system.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Kaouk, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ruoko, T. -P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gonullu, Y. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kaunisto, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mettenborger, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gurevich, E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lemmetyinen, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ostendorf, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mathur, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-415467
DOI:	10.1039/c5ra18330h
Journal or Publication Title:	RSC Adv.
Volume:	5
Number:	123
Page Range:	S. 101401 - 101408
Date:	2015
Publisher:	ROYAL SOC CHEMISTRY
Place of Publication:	CAMBRIDGE
ISSN:	2046-2069
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language NANOSTRUCTURED ALPHA-FE2O3; HEMATITE PHOTOANODES; H-2 PRODUCTION; THIN-FILMS; SOLAR; PHOTOOXIDATION; RECOMBINATION; PERFORMANCE; OXIDE Multiple languages Chemistry, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/41546