Autor/a:
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Tang, Peng-Yi; Han, Li-Juan; Hegner, Franziska Simone; Paciok, Paul; Biset-Peiró, Martí; Du, Hong-Chu; Wei, Xian-Kui; Jin, Lei; Xie, Hai-Bing; Shi, Qin; Andreu, Teresa; Lira-Cantú, Mónica; Heggen, Marc; Dunin-Borkowski, Rafal E.; López, Núria; Galán-Mascarós, José Ramón; Ramon Morante, Joan; Arbiol, Jordi
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Abstract:
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State-of-the-art water-oxidation catalysts (WOCs) in acidic electrolytes
usually contain expensive noble metals such as ruthenium and iridium.
However, they too expensive to be implemented broadly in semiconductor
photoanodes for photoelectrochemical (PEC) water splitting devices. Here,
an Earth-abundant CoFe Prussian blue analogue (CoFe-PBA) is incorporated
with core–shell Fe2O3/Fe2TiO5 type II heterojunction nanowires as composite
photoanodes for PEC water splitting. Those deliver a high photocurrent
of 1.25 mA cm−2 at 1.23 V versus reversible reference electrode in acidic
electrolytes (pH = 1). The enhancement arises from the synergic behavior
between the successive decoration of the hematite surface with nanolayers
of Fe2TiO5 and then, CoFe-PBA. The underlying physical mechanism of
performance enhancement through formation of the Fe2O3/Fe2TiO5/
CoFe-PBA heterostructure reveals that the surface states’ electronic levels
of hematite are modified such that an interfacial charge transfer becomes
kinetically favorable. These findings open new pathways for the future design
of cheap and efficient hematite-based photoanodes in acidic electrolytes. |