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In this study, we report the facile fabrication of Sn-doped hematite film via mid-situ and ex-situ doping methods for efficient photoelectrochemical (PEC) performances. The morphology of Sn-doped Fe 2 O 3 films was varied with Sn precursor in the mid-situ doping process. The addition of SnCl 2 rendered a smooth-surfaced and well-distributed nanorod morphology, but SnCl 4 gave a deformed nanorod structure covered with layered coalescence of SnO 2 particles. The former demonstrated much higher photoelectrochemical performances as photoanodes than the latter. The photocurrent can be further improved by surface modification with SnCl 4 through spin-coating method. The effects of Sn precursors on the morphology, surface characteristics and the PEC properties of the photoanodes are investigated. [ABSTRACT FROM AUTHOR]

Solar hydrogen production via photoelectrochemical water splitting using hematite thin films is a promising approach for the chemical storage of solar energy. Nanorod structured hematite photoanodes provide a direct path for electron collection and hole transport, which have been attracting growing interest. In this study, efficient hematite thin films were synthesized though dissolution and recrystallization of FeOOH nanorods in phosphate solutions. It is found that the morphology and surface characteristic, and PEC photoelectrochemical properties of the hematite films are strongly affected by the aging conditions. The phosphate (NaH 2 PO 4 ) mediated hematite film exhibits 2.1 times higher photocurrent density than that of bare α -Fe 2 O 3 . The influences of phosphate solutions including Na 3 PO 4 , Na 2 HPO 4 and NaH 2 PO 4 , pH values, and aging time on the morphology regulation, isoelectric point, and PEC photoelectrochemical properties of the hematite films are investigated. [ABSTRACT FROM AUTHOR]

Ultrathin hematite films have been prepared on FTO using a separated two-phase hydrolysis–solvothermal reaction. The film thickness can be controlled by the number of deposition cycles. The Photoanode based on hematite film with 7 deposition cycles generated a photocurrent of 0.61 mA cm −2 at +1.5 V vs. RHE. The photocurrent can be improved by coating a layer of reducing graphene oxide (RGO) through spin coating. The enhanced performance is attributed to the promoting effects of RGO which acted as hole collector and transporter in the electrodes. This research demonstrates that graphene can be used as an alternative co-catalyst to enhance photoelectrochemical water splitting activity of ultrathin hematite film. The as-prepared photoanodes were notably stable under water oxidation conditions. [ABSTRACT FROM AUTHOR]

Ultrathin hematite (α-Fe 2 O 3 ) film deposited on a TiO 2 underlayer as a photoanode for photoelectrochemical water splitting was described. The TiO 2 underlayer was coated on conductive fluorine-doped tin oxide (FTO) glass by spin coating. The hematite films were formed layer-by-layer by repeating the separated two-phase hydrolysis-solvothermal reaction of iron(III) acetylacetonate and aqueous ammonia. A photocurrent density of 0.683 mA cm −2 at +1.5 V vs. RHE (reversible hydrogen electrode) was obtained under visible light (>420 nm, 100 mW cm −2 ) illumination. The TiO 2 underlayer plays an important role in the formation of hematite film, acting as an intermediary to alleviate the dead layer effect and as a support of large surface areas to coat greater amounts of Fe 2 O 3 . The as-prepared photoanodes are notably stable and highly efficient for photoelectrochemical water splitting under visible light. This study provides a facile synthesis process for the controlled production of highly active ultrathin hematite film and a simple route for photocurrent enhancement using several photoanodes in tandem. [ABSTRACT FROM AUTHOR]