Hematite Photoanodes: Synergetic Enhancement of Light Harvesting and Charge Management by Sandwiched with Fe2TiO5/Fe2O3/Pt Structures

Efficient charge separation and transport as well as high light absorption are key factors that determine the efficiency of photoelectrochemical (PEC) water splitting devices. Here, we have designed and fabricated a PEC device consisting of a hematite nanoporous film deposited on Pt nanopillars, followed by the decoration with a Fe2TiO5 passivation layer. This structure can largely improve the light absorption in the composite materials, and significantly enhance the water oxidation performance of hematite photoanodes. The Fe2TiO5 thin shell and Pt underlayer significantly improve the interfacial charge transfer while minimizing the hole-migration length in Fe2O3 photoanodes, leading to a drastically increased photocurrent density. Specially, the Fe2TiO5/Fe2O3/Pt photoanode yields an excellent photoresponse for PEC water splitting reactions with 1.0 mA cm-2 and 2.4 mA cm-2 obtained at 1.23 VRHE and 1.6 VRHE under AM 1.5G illumination in 1 M KOH. The resulting photocurrents are 2.5 times enhanced compared to a pristine Fe2O3 photoanode of the same geometry. These results demonstrate a synergistic charge transfer effect of Fe2TiO5 and Pt layers on hematite for the improvement of PEC water oxidation

Hematite Dodecahedron Crystals with High-index Facets Grown and Grafted on One Dimensional Structures for Efficient Photoelectrochemical H2 Generation

Fe2O3 polyhedrons are one of the most promising morphologies for photoelectrochemical water splitting. In spite of recent reports on the successful synthesis of various Fe2O3 polyhedrons, the fabrication of defined photoelectrodes by anchoring the polyhedron in a suitable configuration remains a great challenge. Herein, we introduce a synthetic strategy to prepare Fe2O3 dodecahedrons with high-index {112} facets directly anchored on a one dimensional Fe2O3 nanoflake ({110} facets) electrode. Key is that the Fe2O3 nanoflakes act as seeds for the initiation of the growth of dodecahedral nanocrystals from an iron nitrate solution. The initial single crystals consist of Fe3O4 with exposed {110} basal surfaces that then in a thermal step can be converted to hematite with {112} facets. The resulting single crystal (bi-crystal) hematite photoanode demonstrates a high efficiency for solar water splitting with an excellent photoresponse due to the synergistic effect of direct grafting of the light harvesting and reactive polyhedron and the 1D transport geometry. Under optimized conditions the hematite polyhedrons on nanoflake-structure show photocurrent densities of 2.4 mA cm-2 at 1.23 VRHE and 3.5 mA cm-2 at 1.5 VRHE under AM 1.5G simulated sunlight

In situ preparation of oxygen-deficient TiO₂ microspheres with modified {001} facets for enhanced photocatalytic activity

A facile in situ synthetic strategy has been developed to prepare highly active oxygen-deficient anatase TiO2 microspheres single crystal with modified {001} faceted by simply controlling the hydrothermal reaction time.</p

Advanced oxygen evolution reaction catalysts for solar-driven photoelectrochemical water splitting

Herein, we summarize the recent developments in structure optimizations of oxygen evolution reaction catalysts for promoting photoelectrochemical water splitting performances.</jats:p