Cascaded multiple-step hole transfer for enhancing photoelectrochemical water splitting

Yin, Dan; Ning, Xingming; Du, Peiyao; Zhang, Dongxu; Zhang, Qi; Lu, Xiaoquan

doi:10.1016/j.apcatb.2021.120313

Cited by 19 publications

(15 citation statements)

References 52 publications

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“…Notably, compared to dark conditions, more warm color is clearly seen, revealing that holes from BWO can be in situ -captured and take part in the oxidation reaction of probe molecules, as confirmed by the positive feedback curves. Based on the simplest kinetic model, − the fitting kinetic constant ( K eff ) of relevant photoanodes can be calculated. As shown in Figure c and Table , the K eff increases in the following order: BWO < BWO/BS < BWO/BS/Au < BWO/Au/BS.…”

Section: Resultsmentioning

confidence: 99%

Insights into the Enhanced Photoelectrochemical Performance through Construction of the Z-Scheme and Type II Heterojunctions

et al. 2022

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Photoelectrochemical (PEC) water splitting technology is a promising strategy toward producing sustainable hydrogen fuel. However, it is an essential bottleneck to reduce severe charge recombination for the improvement of PEC performance. Construction of heterojunction systems, such as Z-scheme and type II heterojunctions, could efficiently boost charge separation, whereas the mechanism of charge separation is still ambiguous. We describe herein a charge transfer system designed with Bi 2 WO 6 /Bi 2 S 3 (BWO/BS) as a prototype. In this system, Au nanoparticles act as charge relays to engineer a charge transfer pathway, and the obtained BWO/Au/BS photoanode achieves a remarkable photocurrent density of 0.094 mA cm −2 at 1.23 V versus reversible hydrogen electrode (vs RHE), over approximately 1.2 and 2.3 times larger than those of BWO/BS/Au and BWO, exhibiting long-term photostability. More importantly, scanning photoelectrochemical microscopy (SPECM) and intensity-modulated photocurrent spectroscopy (IMPS) studies are performed to in situ-capture the photogenerated hole during the PEC process. Operando analysis reveals that the Zscheme BWO/Au/BS system (1.33 × 10 −2 cm s −1 ) exhibits higher charge transfer kinetics compared to the type II BWO/BS/Au heterostructure (0.85 × 10 −2 cm s −1 ) while efficiently suppressing charge recombination for optimized PEC activity. Note that this smart strategy can also be extended to other semiconductor-based photoanodes such as BiVO 4 . Our study offers an effective pathway for the rational design of highly efficient charge separation for solar conversion based on water splitting.

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Section: Resultsmentioning

confidence: 99%

Insights into the Enhanced Photoelectrochemical Performance through Construction of the Z-Scheme and Type II Heterojunctions

et al. 2022

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“…[ 35 ] Sulfide heterojunction has been designed as a photoanode with an ultrahigh charge separation efficiency and a solar‐to‐hydrogen conversion efficiency. [ 36 ] Compared with inorganic semiconductors, different molecule materials, such as porphyrin and polyaniline, [ 37 ] nonconjugated polymer, [ 38 ] and covalent triazine‐based polymers, [ 39 ] have been applied for the construction of heterostructure photoanode. Among them, covalent triazine frameworks (CTFs) have been considered as promising candidate for practical PEC application due to tunable electronic structures and donor–acceptor strategy, boosting the collection and transport of charge carrier.…”

Section: Introductionmentioning

confidence: 99%

Boosting Charge Mediation in Ferroelectric BaTiO_3−x‐Based Photoanode for Efficient and Stable Photoelectrochemical Water Oxidation

et al. 2023

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Oxygen evolution reaction (OER) is a bottleneck to photoelectrochemical (PEC) water splitting; however, there remains an impressive challenge for intrinsic charge transport for the development of integrated photoanodes. Herein, covalent triazine frameworks as conjugated molecules are grafted on the surfaces of ferroelectric BaTiO3−x (CTF/BTO) nanorod array, and then oxyhydroxide oxygen evolution cocatalyst (OEC) is constructed as an integrated photoanode. The OEC/CTF/BTO array not only achieves a high photocurrent density of 0.83 mA cm−2 at 1.23 V versus reversible hydrogen electrode (vs RHE) and low onset potential of ≈0.23 VRHE, but also optimizes outstanding stability. To disclose the origin, the enhanced PEC activity can be contributed to the integration of CTF and OEC, enhancing light‐harvesting capability, boosting charge carrier mediation, and promoting water oxidation kinetics through electrochemical analysis and density functional theory calculations. This study not only provides an alternative to accelerate charge transfer, but also paves the rational design and fabrication of integrated photoanodes for boosting PEC water splitting performance.

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“…Based on our previous experience, it is a "consuming" process since Fe 2+ or Ni 2+ ions were added in the electrolyte, serving as the co-catalyst source. Moreover, inserting a hole transport layer (e.g., NiO, 34 porphyrin, and polyaniline 35 ) between the semiconductor and co-catalyst can improve the interfacial quality and extend the lifetime of the PEC device to a certain degree. However, layer-by-layer deposition generally brings cocatalyst detachment and agglomeration and even blocks the active catalytic sites and impedes the charge transfer of reactants, influencing the performance parameter.…”

Section: Introductionmentioning

confidence: 99%

Superhydrophilic CoFe Dispersion of Hydrogel Electrocatalysts for Quasi-Solid-State Photoelectrochemical Water Splitting

Wang,

Gao,

Nguyen

et al. 2023

ACS Nano

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Photoelectrochemical (PEC) water splitting is an attractive strategy to convert solar energy to hydrogen. However, the lifetime of PEC devices is restricted by the photocorrosion of semiconductors and the instability of co-catalysts. Herein, we report a feasible in situ inherent cross-linking method for stabilizing semiconductors that uses a CoFe-dispersed polyacrylamide (PAM) hydrogel as a transparent protector. The CoFe-PAM hydrogel protected BiVO4 (BVO) photoanode reached a photocurrent density of 5.7 mA cm–2 at 1.23 VRHE under AM 1.5G illumination with good stability. The PAM hydrogel network improved the loading of Fe sites while enabling the retention of more CoFe co-catalysts and increasing the electron density of the reaction active sites, further improving the PEC performance and stability. More importantly, by tuning the polymerization network, we pioneer the use of quasi-solid-state electrolytes in photoelectrochemistry, where the high concentration of ionic solvent in the PAM hydrogel ensures effective charge transport and good water storage owing to the hydrophilic and porous structure of the hydrogel. This work expands the scope of PEC research by providing a class of three-dimensional hydrogel electrocatalysts and quasi-solid-state electrolytes with huge extension potential, and the versatility of these quasi-solid-state electrolytes can be employed for other semiconductors.

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Cascaded multiple-step hole transfer for enhancing photoelectrochemical water splitting

Cited by 19 publications

References 52 publications

Insights into the Enhanced Photoelectrochemical Performance through Construction of the Z-Scheme and Type II Heterojunctions

Insights into the Enhanced Photoelectrochemical Performance through Construction of the Z-Scheme and Type II Heterojunctions

Boosting Charge Mediation in Ferroelectric BaTiO_3−x‐Based Photoanode for Efficient and Stable Photoelectrochemical Water Oxidation

Superhydrophilic CoFe Dispersion of Hydrogel Electrocatalysts for Quasi-Solid-State Photoelectrochemical Water Splitting

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Cascaded multiple-step hole transfer for enhancing photoelectrochemical water splitting

Cited by 19 publications

References 52 publications

Insights into the Enhanced Photoelectrochemical Performance through Construction of the Z-Scheme and Type II Heterojunctions

Insights into the Enhanced Photoelectrochemical Performance through Construction of the Z-Scheme and Type II Heterojunctions

Boosting Charge Mediation in Ferroelectric BaTiO3−x‐Based Photoanode for Efficient and Stable Photoelectrochemical Water Oxidation

Superhydrophilic CoFe Dispersion of Hydrogel Electrocatalysts for Quasi-Solid-State Photoelectrochemical Water Splitting

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Boosting Charge Mediation in Ferroelectric BaTiO_3−x‐Based Photoanode for Efficient and Stable Photoelectrochemical Water Oxidation