A Facile Electrochemical Reduction Method for Improving Photocatalytic Performance of alpha-Fe2O3 Photoanode for Solar Water Splitting

作者：Wang Jue; Waters Joseph L; Kung Patrick; Kim Seongsin M; Kelly John T; McNamara Louis E; Hammer Nathan I; Pemberton Barry C; Schmehl Russell H; Gupta Arunava; Pan Shanlin^*

来源：ACS Applied Materials & Interfaces, 2017, 9(1): 381-390.

DOI：10.1021/acsami.6b11057

• hematite
• magnetite
• water splitting solar energy
• electrochemical reduction

Electrochemical reduction method is used for the first time to significantly improve the photo-electrochemical performance of alpha-Fe2O3 photoanode prepared on fluorine doped tin oxide substrates by spin-coating aqueous solution of Fe(NO3)(3) followed by thermal annealing in air. Photocurrent density of alpha-Fe2O3 thin film photoanode can be enhanced 25 times by partially reducing the oxide film to forth more conductive Fe3O4 (magnetite). Fe3O4 helps facilitate efficient charge transport and collection from the top alpha-Fe2O3 layer upon light absorption and charge separation to yield enhanced photocutrent density. The optimal enhancement can be obtained for <50 nm films because of the short charge-transport distance for the alpha-Fe2O3 layer. Thick alpha-Fe2O3 films require more charge and overpotential than thinner films to achieve limited enhancement because of the-sluggish, charge transport over a longer distance to oxidize water. Electrochemical reduction of alpha-Fe2O3 in unbuffered pH-neutral solution yields much higher but unstable photocurrent enhancement because of the increase in local pH value accompanied by proton reductionlat a hematite surface.

• 出版日期2017-1-11