Engineered Sn- and Mg-doped hematite photoanodes for efficient photoelectrochemical water oxidation

Cai, Jiajia; Chen, Hao; Liu, Cunxing; Yin, Shuaiqi; Li, Haijin; Xu, Liangcheng; Líu, Hao; Xie, Qian

doi:10.1039/c9dt03962g

Cited by 27 publications

(29 citation statements)

References 36 publications

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“…Doping with Zr 4+ , 5,6 Ti 4+ , 7 Sn 4+ , 8 Nb 5+ , 9 Ni 2+ , 10 and Mg 2+ , 11,12 is an approach to overcome the low electrical conductivity of hematite and improve its photocatalytic activities. Some of these observations demonstrated that the conductivity was improved due to the small polaron hopping mechanism, which leads to the enhancement of PEC properties 13–15 .…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] However, its PEC application has been limited due to poor electrical conductivity, short charge carrier lifetime (<10 ps), and high recombination rate as a result of short hole diffusion length (2-4 nm). 4 Doping with Zr 4+ , 5,6 Ti 4+ , 7 Sn 4+ , 8 Nb 5+ , 9 Ni 2+ , 10 and Mg 2+ , 11,12 is an approach to overcome the low electrical conductivity of hematite and improve its photocatalytic activities. Some of these observations demonstrated that the conductivity was improved due to the small polaron hopping mechanism, which leads to the enhancement of PEC properties.…”

Section: Introductionmentioning

confidence: 99%

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Photoelectrochemical properties of butane reduced flame‐treated Zr‐doped hematite thin films

2022

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In this research, Zr‐doped hematite thin films were prepared by a simple and highly scalable liquid phase deposition method, and their photoelectrochemical (PEC) properties were investigated. The samples were post‐heat treated using a butane reduced flame. PEC studies revealed that both Zr‐doping and flame‐treatment enhanced the performance of the hematite photoanodes. The photocurrent densities of the samples were considerably increased upon flame‐treatment, that is, about 3.5 times for a 4% Zr‐doped sample. The highest photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) was obtained, about 0.50 mA cm−2 for the 4% Zr‐doped sample, about five times higher than the undoped sample. The Mott–Schottky measurements revealed that the donor charge carrier density for the 4% Zr‐doped sample was increased fivefold upon flame‐treatment from 2.49 × 1019 to 1.38 × 1020 cm−3. The optical investigations showed that the optical band gap energy values depend on the level of Zr‐doping, and the sample with 4% Zr‐doping showed the lowest band gap energy value, about 1.82 eV. The mechanism behind the effectiveness of the flame‐treatment was investigated and attributed to the oxygen vacancy formation upon flame‐treatment. The formation of oxygen vacancies activates the donor doping, and as a result, the charge carrier density increases. In general, butane reduced flame‐treatment as a simple and effective strategy can be used as a post‐heat treatment to boost the PEC properties of hematite thin films.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photoelectrochemical properties of butane reduced flame‐treated Zr‐doped hematite thin films

2022

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“…24 pristine α-Fe 2 O 3 photoanodes for PEC water oxidation, as indicated in Table S1, 28−36 including the highest IPCE (IPCE 420 ) of 36% at 420 nm for cauliflower α-Fe 2 O 3 prepared by the atmospheric pressure chemical vapor deposition (APCVD) technique. 32 Although α-Fe 2 O 3 -based photoanodes have been fabricated via various physical and chemical techniques such as chemical vapor deposition, 37−39 ultrasonic spray pyrolysis, 40 atomic layer deposition, 41 dense solutionbased regrown, 42 e-beam evaporation, 43 electrodeposition, 44 and hydrothermal, 36 a facile way available for mass production of α-Fe 2 O 3 photoanodes is mandatory for practical systems of solar-driven water splitting. Recently we found that the presence of 1-methylimidazole in precursor methanolic solutions (or suspensions) containing metal ions leads to rigidly adhered films of the corresponding metal oxides on various electrode substrates upon sintering.…”

Section: ■ Introductionmentioning

confidence: 99%

Facile Fabrication of a Highly Crystalline and Well-Interconnected Hematite Nanoparticle Photoanode for Efficient Visible-Light-Driven Water Oxidation

Katsuki

Zahran

Tanaka

et al. 2021

ACS Appl. Mater. Interfaces

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Facile and scalable fabrication of α-Fe 2 O 3 photoanodes using a precursor solution containing Fe III ions and 1-ethylimidazole (EIm) in methanol was demonstrated to afford a rigidly adhered α-Fe 2 O 3 film with a controllable thickness on a fluorine-doped tin oxide (FTO) substrate. EIm ligation to Fe III ions in the precursor solution brought about high crystallinity of three-dimensionally well-interconnected nanoparticles of α-Fe 2 O 3 upon sintering. This is responsible for the 13.6 times higher photocurrent density (at 1.23 V vs reference hydrogen electrode (RHE)) for photoelectrochemical (PEC) water oxidation on the α-Fe 2 O 3 (w-α-Fe 2 O 3 ) photoanode prepared with EIm compared with that (w/o-α-Fe 2 O 3 ) prepared without EIm. The w-α-Fe 2 O 3 photoanode provided the highest charge separation efficiency (η sep ) value of 27% among the state-of-the-art pristine α-Fe 2 O 3 photoanodes, providing incident photon-to-current conversion efficiency (IPCE) of 13% at 420 nm and 1.23 V vs RHE. The superior η sep for the w-α-Fe 2 O 3 photoanode is attributed to the decreased recombination of the photogenerated charge carriers at the grain boundary between nanoparticles, in addition to the higher number of the catalytically active sites and the efficient bulk charge transport in the film, compared with w/o-α-Fe 2 O 3 .

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“…A few reports are available in the literature on the study of photoconversion and water-splitting efficiency of Mg-doped iron oxide as adsorbents of various chemicals. [8][9][10] A study undertaken by Ingler et al [8] using Mg-doped iron (III) oxide thin films prepared by spray pyrolysis reported a maximum photoconversion efficiency of 0.33%. A hydrothermal method was utilized by Cai et al [9] to prepare tin and magnesium co-doped hematite films as photoanode for water splitting that attained a maximum photocurrent density of 1.1 mA cm À2 , which was better than the pristine α-Fe 2 O 3 by three times.…”

Section: Introductionmentioning

confidence: 99%

“…[8][9][10] A study undertaken by Ingler et al [8] using Mg-doped iron (III) oxide thin films prepared by spray pyrolysis reported a maximum photoconversion efficiency of 0.33%. A hydrothermal method was utilized by Cai et al [9] to prepare tin and magnesium co-doped hematite films as photoanode for water splitting that attained a maximum photocurrent density of 1.1 mA cm À2 , which was better than the pristine α-Fe 2 O 3 by three times. The improvement in its performance was ascribed to the increase in charge injection efficiency and charge separation efficiency due to Mg doping.…”

Section: Introductionmentioning

confidence: 99%

Influence of Magnesium Doping on the Photocatalytic and Antibacterial Properties of Hematite Nanostructures

Joseph¹,

Nair²,

Mary³

et al. 2021

Physica Status Solidi (b)

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Herein, the effect of magnesium doping on hematite nanostructures prepared by a simple and cost‐effective electrochemical method is reported. Photocatalytic and antibacterial studies on the undoped and doped samples suggest improved performance for the Mg‐doped samples. Structural studies using X‐ray diffraction, Raman spectroscopy, and X‐ray photoelectron spectroscopy (XPS) in combination with field‐emission scanning electron microscopy for surface morphology confirm the Mg presence in the nanostructured hematite phase of iron oxide. Analyses of the valence band (VB) XPS spectra along with optical reflectance spectra indicate a shift in VB edge, characteristic of a conductivity type conversion from n‐type in hematite to p‐type in Mg‐doped hematite. The room temperature electrical conductivity is increased by three orders, and the optical bandgap is reduced by around 0.08 eV for moderately doped hematite nanostructures.

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Engineered Sn- and Mg-doped hematite photoanodes for efficient photoelectrochemical water oxidation

Abstract: A feasible and cost-effective method was developed to improve the photoelectrochemical performance of hematite (α-Fe2O3) photoanode. Using a hydrothermal method, tin (Sn) and magnesium (Mg) (co-)doped hematite films were prepared...

Cited by 27 publications

References 36 publications

Photoelectrochemical properties of butane reduced flame‐treated Zr‐doped hematite thin films

Photoelectrochemical properties of butane reduced flame‐treated Zr‐doped hematite thin films

Facile Fabrication of a Highly Crystalline and Well-Interconnected Hematite Nanoparticle Photoanode for Efficient Visible-Light-Driven Water Oxidation

Influence of Magnesium Doping on the Photocatalytic and Antibacterial Properties of Hematite Nanostructures

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