Tin and Oxygen-Vacancy Co-doping into Hematite Photoanode for Improved Photoelectrochemical Performances

Abstract

Hematite (α-Fe 2 O 3 ) material is regarded as a promising candidate for solar-driven water splitting because of the low cost, chemical stability, and appropriate bandgap; however, the corresponding system performances are limited by the poor electrical conductivity, short diffusion length of minority carrier, and sluggish oxygen evolution reaction. Here, we introduce the in situ Sn doping into the nanoworm-like α-Fe 2 O 3 film with ultrasonic spray pyrolysis method. We show that the current density at 1.23 V vs. RHE (J ph@1.23V ) under one-sun illumination can be improved from 10 to 130 μA/cm 2 after optimizing the Sn dopant density. Moreover, J ph@1.23V can be further enhanced 25folds compared to the untreated counterpart via the post-rapid thermal process (RTP), which is used to introduce the defect doping of oxygen vacancy. Photoelectrochemical impedance spectrum and Mott-Schottky analysis indicate that the performance improvement can be ascribed to the increased carrier density and the decreased resistances for the charge trapping on the surface states and the surface charge transferring into the electrolyte. Xray photoelectron spectrum and X-ray diffraction confirm the existence of Sn and oxygen vacancy, and the potential influences of varying levels of Sn doping and oxygen vacancy are discussed. Our work points out one universal approach to efficiently improve the photoelectrochemical performances of the metal oxide semiconductors.

Non‐Parallel Photo‐Assisted Electrocatalysis Mechanism of SnS2/NiO Heterojunction for Efficient Electrocatalytic Oxygen Evolution Reaction

“…It is reported that heteroatoms doping is very similar to the regulation of adsorbed oxygen content in oxides. [37,38] So the ratio of lattice oxygen to adsorbed oxygen of SnS 2 /NiO decreases to 1.56. In addition, the O 1s spectra of SnS 2 /NiO with different NiO contents are shown in Figure S4.…”

Laser-Induced Photoreduction for Selective Tuning of the Oxidation State and Crystal Structure of Hematite Nanorods

“…It is generally accepted that the OVs in hematite serve as electron donors, resulting in improved electrical conductivity. [6][7][8][9]56 The donor density (N d ) of the samples was estimated using Mott− Schottky analysis. Figure 5a In an electrochemical cell, the bulk capacitance (C bulk ) of an electrode is related to the applied potential (V) by the Mott− Schottky equation as follows…”

“…The ability of hematite to achieve a high water oxidation performance, however, has been hindered by its low electrical conductivity (10 –14 Ω –1 cm –1 ), extremely short photoexcited carrier lifetime, and tiny minority carrier diffusion length . The introduction of oxygen vacancy (OV) in a nanostructured hematite thin film has been regarded as an effective method which enhances its PEC performance. − OV is a type of defect that may be present in metal oxides . Two electrons are left by each missing oxygen atom in the hematite lattice .…”

Correction to: Tin and Oxygen-Vacancy Co-doping into Hematite Photoanode for Improved Photoelectrochemical Performances

“…Following publication of the original article [ 1 ], it came to the authors’ attention that an incomplete version of affiliation 1 had been provided; ‘Soochow University’ was missing from the affiliation.…”