Boosting the performance of delafossite photocathode through constructing a CuFeO2/CuO heterojunction for photoelectrochemical water reduction

Jiang, Tengfei; Zhao, Yu; Xue, Huaiguo

doi:10.1007/s10853-019-03747-7

Cited by 27 publications

(8 citation statements)

References 31 publications

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“…First-principles calculations can provide valuable insights into the operation of CFO photocathodes. Previously, simulations have been used to characterize the magnetic properties of CFO, , and more recently, these investigations have shifted, focusing instead on the electronic properties related to the CFO photocathodic performance. ,,− Despite this interest, the nature of the electrode surface when exposed to an aqueous environment, which can be a large driving force in the overall photoelectrochemical properties, has yet to be reported either from theory or experimental work. This is surprising since, from a theoretical perspective, CFO surfaces have been the subject of investigation for CO 2 reduction. , Recent theoretical work has instead addressed the stability and propensity for defect formation in the bulk phase in dry and electrochemical conditions as well as the bulk electronic properties. , It was found that the liquid environment acts to stabilize the bulk CFO phase relative to other oxides in the region corresponding to experimental measurement, but the analysis does not account for different exposed surface stabilities, chemistry, or reconstructions.…”

Section: Introductionmentioning

confidence: 99%

CuFeO₂–Water Interface under Illumination: Structural, Electronic, and Catalytic Implications for the Hydrogen Evolution Reaction

et al. 2021

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CuFeO 2 is a p-type semiconductor that has been recently identified as a promising photocathode material for photoelectrochemical water splitting. CuFeO 2 can absorb solar light and promote the hydrogen evolution reaction (HER), even though the photocurrents achieved so far are still well below the theoretical upper limit. While several experimental and theoretical works have provided a detailed characterization of the bulk properties of this material, surfaces have been largely unexplored. In this work, we perform firstprinciples simulations based on DFT to investigate the structure, electronic properties, and thermodynamic stability of CuFeO 2 surfaces both in vacuum and in an electrochemical environment. To estimate the alignment of the band edges on the electrochemical scale, we perform ab initio molecular dynamics in explicit water, unraveling the structure of the solid/liquid interface for various surface terminations. We consider the system both in the dark and under illumination, showing that light absorption can induce partial reduction of the surface, giving rise to states in the gap that can pin the Fermi level, in agreement with recent measurements. Using the free energy of adsorption of atomic hydrogen as a descriptor of the catalytic activity for the HER, we show that hydride species formed at oxygen vacancies can be highly active and could therefore be an intermediate of reaction.

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Section: Introductionmentioning

confidence: 99%

CuFeO₂–Water Interface under Illumination: Structural, Electronic, and Catalytic Implications for the Hydrogen Evolution Reaction

et al. 2021

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“…Heterojunction formation is an effective avenue to promote carrier separation of photogenerated carriers and thus improve photocatalytic properties. − The XRD patterns of TiO 2 synthesized by the hydrothermal method and CFO/TiO 2 heterojunctions with varied ratios are shown, wherein pure TiO 2 annealed under the same condition was also characterized for comparison. It suggests that the as-synthesized TiO 2 is basically B-type and the phase is retained even after annealing at 100 °C (Figure a).…”

Section: Resultsmentioning

confidence: 99%

Construction of Ca-CuFeO₂/TiO₂(B) p–n Heterojunctions with Efficient Visible Light-Driven Photocatalysis

Deng

Shi

et al. 2023

J. Phys. Chem. C

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Ca-CuFeO2/TiO2(B) heterojunctions were constructed to improve the photocatalytic reduction efficiency of Cr(VI). The results suggest that Ca doping gives rise to the phase transition of 3R to 2H, increased surface area, and improved charge transfer ability of CuFeO2. Covering CuFeO2 with TiO2(B) effectively inhibits the partial oxidization of Cu1+ to Cu2+. The schematic energy band diagram and carrier density distributions for Ca-CFO/TiO2 heterojunctions were theoretically simulated using AMPS software. It suggests that photogenerated electrons in the CuFeO2 conduction band adjacent to the depletion region drift into TiO2(B) due to the presence of a built-in electric field to directly participate in the reducing process of Cr(VI) on the TiO2 surface. Photogenerated holes in CuFeO2 can hardly drift or diffuse into TiO2(B) due to the presence of an energy barrier in the valence band and will diffuse to the uncovered CuFeO2 surface and be captured by formic acid to generate reactive CO2·– free radicals to effectively reduce Cr(VI). The maximum photocatalytic efficiency using 5%Ca-CuFeO2/TiO2 (3:1) was 100% in 40 min. The study results can provide a new avenue for the efficient treatment of Cr(VI)-containing wastewater with Ca-CuFeO2/TiO2(B) p–n heterojunctions owing to the advantages of high efficiency, environmental friendliness, sustainability, and low energy consumption.

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“…6 Despite the fundamental band gap of approximately 1.5 eV enabling CuFeO 2 to absorb the entirety of visible and near-infrared light within the solar spectrum, the narrowband gap predisposes it to a heightened risk of photogenerated electron-hole pair recombination, which bodes unfavorably for its industrial uptake. 7 Responding to this challenge, researchers have ventured into different avenues of material modification for CuFeO 2 , incorporating methods like doping engineering, 8 solid solution design, 9,10 heterostructure construction, 11,12 precious metal loading, 13 and dye sensitization. 14 Each strategy has evinced considerable enhancements in both photocatalytic and photoelectrocatalytic performance.…”

Section: Introductionmentioning

confidence: 99%

Tailoring doping locations and types for high‐performance CuFeO₂‐based photocatalysts

Yu,

Zhao

2023

J Am Ceram Soc.

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Doping engineering has been recognized as an effective strategy for improving the solar‐to‐hydrogen conversion efficiency of delafossite CuFeO2‐based photocatalysts. However, a comprehensive and systematic study on the doping effect in CuFeO2 is still needed to establish a universal law. To address this, we utilized density functional theory calculations to scrutinize the doping effects of various dopants at different lattice positions. Our findings revealed that Mn replacing Fe and N replacing O are the most readily achievable doping methods under oxygen‐rich and oxygen‐poor conditions, respectively, with a maximum doping concentration of 1020 cm−3 achievable at 900 K. Interestingly, we found that doping with N for O, F for O, and Ni for Cu generates impurity levels capable of capturing photogenerated holes at the top of the valence band, while Zn for Cu and Co for Fe engender impurity levels capable of capturing photogenerated electrons at the bottom of the conduction band, thereby facilitating the separation of photogenerated electron–hole pairs. However, it is worth highlighting that Mn replacing Fe results in impurity levels forming in the middle of the bandgap, acting as a recombination center for photogenerated electron–hole pairs. Furthermore, we discovered that Mg replacing Cu or Fe serves as an example of heterovalent doping capable of promoting the solar‐to‐hydrogen conversion efficiency of CuFeO2. In isovalent doping, dopants with more valence electrons than Cu, dopants with the same valence electron as Fe, and dopants with less valence electron than O can enhance the solar‐to‐hydrogen conversion efficiency of CuFeO2. Overall, this study provides a systematic analysis of the doping effects on CuFeO2‐based photocatalysts and can be applied to doping engineering of ABO2‐type delafossite photocatalytic materials.

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Boosting the performance of delafossite photocathode through constructing a CuFeO2/CuO heterojunction for photoelectrochemical water reduction

Cited by 27 publications

References 31 publications

CuFeO₂–Water Interface under Illumination: Structural, Electronic, and Catalytic Implications for the Hydrogen Evolution Reaction

CuFeO₂–Water Interface under Illumination: Structural, Electronic, and Catalytic Implications for the Hydrogen Evolution Reaction

Construction of Ca-CuFeO₂/TiO₂(B) p–n Heterojunctions with Efficient Visible Light-Driven Photocatalysis

Tailoring doping locations and types for high‐performance CuFeO₂‐based photocatalysts

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Boosting the performance of delafossite photocathode through constructing a CuFeO2/CuO heterojunction for photoelectrochemical water reduction

Cited by 27 publications

References 31 publications

CuFeO2–Water Interface under Illumination: Structural, Electronic, and Catalytic Implications for the Hydrogen Evolution Reaction

CuFeO2–Water Interface under Illumination: Structural, Electronic, and Catalytic Implications for the Hydrogen Evolution Reaction

Construction of Ca-CuFeO2/TiO2(B) p–n Heterojunctions with Efficient Visible Light-Driven Photocatalysis

Tailoring doping locations and types for high‐performance CuFeO2‐based photocatalysts

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Product

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CuFeO₂–Water Interface under Illumination: Structural, Electronic, and Catalytic Implications for the Hydrogen Evolution Reaction

CuFeO₂–Water Interface under Illumination: Structural, Electronic, and Catalytic Implications for the Hydrogen Evolution Reaction

Construction of Ca-CuFeO₂/TiO₂(B) p–n Heterojunctions with Efficient Visible Light-Driven Photocatalysis

Tailoring doping locations and types for high‐performance CuFeO₂‐based photocatalysts