Phase-junction design of MOF-derived TiO2 photoanodes sensitized with quantum dots for efficient hydrogen generation

Shi, Li; Benetti, Daniele; Li, Faying; Wei, Qin; Rosei, Federico

doi:10.1016/j.apcatb.2019.118317

Cited by 74 publications

(51 citation statements)

References 61 publications

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“…[45g] In addition to homogeneous metal oxides, it has been shown that the rational combinations of multiple metal oxides into heterostructures can promote the separation of photogenerated excitons, such as SnO 2 -TiO 2 heterojunctions. [95] Recently, Li et al designed a controlled mixed-phase TiO 2 (anatase and rutile) by using MOF as a template to retain the crystal morphology [85] (Figure 3e). The mixed TiO 2 phases created a favorable band energy alignment for the built-in electric fields which significantly suppressed the recombination of photogenerated carriers, thereby efficiently separating the photogenerated charges.…”

Section: Engineering Electron Acceptor Materialsmentioning

confidence: 99%

“…[ 95 ] Recently, Li et al. designed a controlled mixed‐phase TiO 2 (anatase and rutile) by using MOF as a template to retain the crystal morphology [ 85 ] (Figure 3e). The mixed TiO 2 phases created a favorable band energy alignment for the built‐in electric fields which significantly suppressed the recombination of photogenerated carriers, thereby efficiently separating the photogenerated charges.…”

Section: Qds‐based Pec Systemmentioning

confidence: 99%

“…[ 127e,147 ] For example, for a thick‐shell CdSe/CdS QD‐based PEC TiO 2 photoanode, the initial current density remained 57.5% after 2 h of continuous 1 sun irradiation, which is better than the CdSe‐sensitized TiO 2 under identical conditions (42.1% retention of photocurrent). [ 85 ] However, the thick shell might decelerate or even block hole transfer. [ 44c,d,65 ] The consequent hole accumulation may cause the surface oxidation of the QDs, thus increasing the surface charge recombination centers and leading to the degradation of QDs under illumination.…”

Section: Qds‐based Pec Systemmentioning

confidence: 99%

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Quantum Dots‐Based Photoelectrochemical Hydrogen Evolution from Water Splitting

Liu

Zhao

Wang

et al. 2021

Advanced Energy Materials

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opportunity since it is by far the most abundant, sustainable, carbon-neutral, and inexpensive energy source. The theoretical potential of solar power striking the earth's surface is ≈89 300 TW (the integral of the time-and-space-averaged solar flux 342.5 W m −2 over the earth's surface area 5.11 × 10 14 m 2 , estimating that ≈30% and ≈19% are scattered and absorbed by the atmosphere and clouds), [3] which is equivalent to ≈6000 times the power used worldwide every year (estimated at 13.5 TW in 2001, with projected growth up to 27.6 TW by 2050 by the Intergovernmental Panel on Climate Change). [4] In particular, storing solar energy in the form of H 2 presents advantages such as high energy content per mass (143 MJ kg −1), ease of transportation, and cost-effectiveness, [5] thereby addressing the storage challenge which is associated with the diffuse and intermittent character of solar irradiation. Solar energy and water could be converted into H 2 [5b] indirectly by using solar-converted electricity and an electrolyzer, [6] concentrated solar thermal and an electrolyzer, [7] biological and thermochemical processes [8] or directly by photo-/photoelectrocatalysis of water. [1b,f,g] The combination of the energy conversion step with electrolyzers is always limited by the performance of the electrolyzers, whose typical commercial efficiencies are around 73%. [9] Besides, indirect technologies suffer from excessive cost, area requirements, feasibility issues, or energy loss. [10] An alternative direct route is the photo-/photoelectrocatalysis of water, including powdered photocatalysts [11] and photoelectrochemical (PEC) cells. [12] The dispersion of powdered photocatalysts in water is suitable for large-scale processes, while the system requires stirring during the reaction and product separation after the reaction. In comparison, PEC systems (Figure 1a), which combine harvesting solar energy with water reduction into a single device, possesses several advantages. [13] i) PEC reactions address the issue of gas separation by generating products at different electrodes. ii) An external bias supply or self-bias voltage in the PEC system can provide additional energy input to compensate for the potential deficiency, [14] leading to the formation of a surface space charge layer and achieving efficient charge separation and an increased number of long-living photogenerated charges. [15] iii) Moreover, PEC systems can potentially be operated using only stable and abundant materials, such as Cu-based metal oxides, [16] Fe 2 O 3 , [14b,17] and TiO 2. [18] In a typical PEC system, at least one photoelectrode is used as a working electrode to harvest solar radiation, either acting Solar-driven photoelectrochemical (PEC) hydrogen evolution is a promising and sustainable approach to convert solar energy into a fuel that can be stored. Semiconductor quantum dots (QDs) are increasingly used in PEC devices due to their broad composition/size/shape tunable absorption spectrum (from ultraviolet to near-infrared, with significant over...

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Section: Engineering Electron Acceptor Materialsmentioning

confidence: 99%

Section: Qds‐based Pec Systemmentioning

confidence: 99%

Section: Qds‐based Pec Systemmentioning

confidence: 99%

See 1 more Smart Citation

Quantum Dots‐Based Photoelectrochemical Hydrogen Evolution from Water Splitting

Liu

Zhao

Wang

et al. 2021

Advanced Energy Materials

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“…141 Garcia et al were the first to recognize that F I G U R E 1 4 JV curves for TiO 2 modified with MOF electrodes. (A) Replicated with consent 83 Copyright 2019 Elsevier, (B) 84 Exclusive rights 2015 John Wiley and Sons, (C) 87 Exclusive rights 2019 Elsevier, (D) 139 Exclusive rights 2013 Royal Society of Chemistry, (E) 140 Exclusive rights 2013 Elsevier, (F) 141 Exclusive rights 2020 Elsevier [Colour figure can be viewed at wileyonlinelibrary.com] Zr-containing MOF can be effectively utilized for photocatalytic hydrogen generation. Later, it was observed that graphene wrapping around NH 2 -MIL-125(Ti) through electrostatic interaction could develop contact between graphene and MOF.…”

Section: F I G U R E 1mentioning

confidence: 99%

“…JV curves for TiO 2 modified with MOF electrodes. (A) Replicated with consent 83 Copyright 2019 Elsevier, (B) 84 Exclusive rights 2015 John Wiley and Sons, (C) 87 Exclusive rights 2019 Elsevier, (D) 139 Exclusive rights 2013 Royal Society of Chemistry, (E) 140 Exclusive rights 2013 Elsevier, (F) 141 Exclusive rights 2020 Elsevier [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Recent Advances In Water‐splitting By Mof‐based Catalystsmentioning

confidence: 99%

Recent advancements in MOF‐ based catalysts for applications in electrochemical and photoelectrochemical water splitting: A review

et al. 2020

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Summary A significant interest in the exploration of clean and renewable alternative energy resources has been observed in recent years to combat environmental pollution and energy shortages for a sustainable future. In this regard, hydrogen is clean, energy‐rich fuel with unlimited potential. It can be produced via water‐splitting process using the most abundant resources on earth, that is, water and solar/electrical energy. Metal‐organic frameworks (MOFs) are a category of porous crystalline materials with well‐organized structures and unique catalytic, optical, and electrical properties. MOFs and MOF‐derived materials have proved to be excellent catalysts for water‐splitting both by electrochemical and photoelectrochemical (PEC) routes. Furthermore, photochemical and electrochemical capabilities of these MOFs can be fine‐tuned to maximize their performance by modification in the bandgap, surface area, current density, electrochemical active surface area, and overpotential, through tailoring of the organic ligands and/or metal centers. A number of works have been dedicated to this quest resulting in promising and very effective results. Such as for photoelectrocatalysis, a composite nanorod array of TiO2/Co‐MOF acting as photoanode achieved one of the highest photocurrent densities of 2.93 mA/cm2 at 1.23 V (vs reverse hydrogen electrode [RHE]). In another study, MOF‐derived Co3C‐3/TiO2 photoanode attained the photocurrent density of 2.6 mA/cm2 at 1.23 V vs RHE. For electrocatalysis, Fe2O3/Ni‐MOF‐74 exhibited oxygen evolution reaction overpotential of 264 mV to reach 10 mA/cm2 of current density with a low Tafel plot of 48 mV/dec. Another novel material derived from MOF, MoO2‐PC‐rGO displayed a Tafel Plot of 41 mV/dec. Even though this field is in its infancy phase, it is attracting increased attention for promising results suggesting extraordinary potential for practical applications. Focus of this review article is on the overview of the development of MOFs for application in electrocatalytic and photoelectrocatalytic water‐splitting for hydrogen production. This review intends to provide a timely reference and insight for the advancement in catalysts based on MOFs for practical electrochemical and PEC water‐splitting in a clear and comprehensive manner. Starting with the brief introduction, fundamentals, factors affecting catalytic efficiency and evaluation parameters of water‐splitting are summarized followed by synthesis strategies and recent progress made by MOF‐based catalysts for PEC and electrochemical water‐splitting.

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