000185561 001__ 185561
000185561 005__ 20181203023048.0
000185561 0247_ $$2doi$$a10.1039/c2cp42597a
000185561 022__ $$a1463-9076
000185561 02470 $$2ISI$$a000313565300014
000185561 037__ $$aARTICLE
000185561 245__ $$aFormation of an electron hole doped film in the alpha-Fe2O3 photoanode upon electrochemical oxidation
000185561 260__ $$bRoyal Society of Chemistry$$c2013$$aCambridge
000185561 269__ $$a2013
000185561 300__ $$a9
000185561 336__ $$aJournal Articles
000185561 520__ $$aSolar hydrogen generation by water splitting in photoelectrochemical cells (PEC) is an appealing technology for a future hydrogen economy. Hematite is a prospective photoanode material in this respect because of its visible light conjugated band gap, its corrosion stability, its environmentally benign nature and its low cost. Its bulk and surface electronic structure has been under scrutiny for many decades and is considered critical for improvement of efficiency. In the present study, hematite films of nominally 500 nm thickness were obtained by dip-coating on fluorine doped tin oxide (FTO) glass slides and then anodised in 1 molar KOH at 500, 600, and 700 mV for 1, 10, 120 and 1440 minutes under dark conditions. X-ray photoelectron spectra recorded at the Fe 3p resonant absorption threshold show that the e(g) transition before the Fermi energy, which is well developed in the pristine hematite film, becomes depleted upon anodisation. The spectral weight of the e(g) peak decreases with the square-root of the anodisation time, pointing to a diffusion controlled process. The speed of this process increases with the anodisation potential, pointing to Arrhenius behaviour. Concomitantly, the weakly developed t(2g) peak intensity becomes enhanced in the same manner. This suggests that the surface of the photoanode contains Fe2+ species which become oxidized toward Fe3+ during anodisation. The kinetic behaviour derived from the experimental data suggests that the anodisation forms an electron hole doped film on and below the hematite surface.
000185561 700__ $$uEmpa Swiss Fed Labs Mat Sci & Technol, Lab High Performance Ceram, CH-8600 Dubendorf, Switzerland$$aGajda-Schrantz, Krisztina
000185561 700__ $$uEmpa Swiss Fed Labs Mat Sci & Technol, Lab High Performance Ceram, CH-8600 Dubendorf, Switzerland$$aTymen, Simon
000185561 700__ $$uEmpa Swiss Fed Labs Mat Sci & Technol, Lab High Performance Ceram, CH-8600 Dubendorf, Switzerland$$aBoudoire, Florent
000185561 700__ $$uEmpa Swiss Fed Labs Mat Sci & Technol, Lab High Performance Ceram, CH-8600 Dubendorf, Switzerland$$aToth, Rita
000185561 700__ $$uEmpa Swiss Fed Labs Mat Sci & Technol, Lab High Performance Ceram, CH-8600 Dubendorf, Switzerland$$aBora, Debajeet K.
000185561 700__ $$uTech Univ Darmstadt, Ctr Smart Interfaces, D-64287 Darmstadt, Germany$$aCalvet, Wolfram
000185561 700__ $$0240191$$g105292$$aGraetzel, Michael
000185561 700__ $$uUniv Basel, Dept Chem, CH-4056 Basel, Switzerland$$aConstable, Edwin C.
000185561 700__ $$aBraun, Artur$$uEmpa Swiss Fed Labs Mat Sci & Technol, Lab High Performance Ceram, CH-8600 Dubendorf, Switzerland
000185561 773__ $$j15$$tPhysical Chemistry Chemical Physics$$k5$$q1443-1451
000185561 909C0 $$xU10101$$0252060$$pLPI
000185561 909CO $$pSB$$particle$$ooai:infoscience.tind.io:185561
000185561 917Z8 $$x105528
000185561 937__ $$aEPFL-ARTICLE-185561
000185561 973__ $$rREVIEWED$$sPUBLISHED$$aEPFL
000185561 980__ $$aARTICLE