title: An Optically Transparent Iron Nickel Oxide Catalyst for Solar Water Splitting.
abstract: Sunlight-driven water splitting to produce hydrogen fuel is an attractive method for renewable energy conversion. Tandem photoelectrochemical water splitting devices utilize two photoabsorbers to harvest the sunlight and drive the water splitting reaction. The absorption of sunlight by electrocatalysts is a severe problem for tandem water splitting devices where light needs to be transmitted through the larger bandgap component to illuminate the smaller bandgap component. Herein, we describe a novel method for the deposition of an optically transparent amorphous iron nickel oxide oxygen evolution electrocatalyst. The catalyst was deposited on both thin film and high-aspect ratio nanostructured hematite photoanodes. The low catalyst loading combined with its high activity at low overpotential results in significant improvement on the onset potential for photoelectrochemical water oxidation. This transparent catalyst further enables the preparation of a stable hematite/perovskite solar cell tandem device, which performs unassisted water splitting.
authors.affiliation: †Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Carlos G
authors.initials: CG
authors.lastname: Morales-Guio
authors.affiliation: ‡Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Mayer
authors.affiliation: ‡Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Aswani
authors.initials: A
authors.lastname: Yella
authors.affiliation: ‡Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: S David
authors.initials: SD
authors.lastname: Tilley
authors.affiliation: ‡Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.affiliation: †Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Xile
authors.initials: X
authors.lastname: Hu