Band structure engineering and defect control of Ta3N5 for efficient photoelectrochemical water oxidation

Xiao, Yequan; Feng, Chao; Fu, Jie; Wang, Faze; Li, Changli; Kunzelmann, Viktoria F.; Jiang, Chunsheng; Nakabayashi, Mamiko; Shibata, Naoya; Sharp, Ian D.; Domen, Kazunari; Li, Yanbo

doi:10.1038/s41929-020-00522-9

Cited by 257 publications

(206 citation statements)

References 47 publications

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“…For the photoactivated samples from 6 to 20 h, both τ 1 and τ 2 become longer, and the fractional intensity of the fast component ( ƒ 1 ) decreases, suggesting that the induced oxygen vacancies effectively suppress the defect‐related charge recombination. [ 39,40 ] In contrast, after 45 h of electrode, the lifetime decreases, coinciding with the above‐described PEC results. These results highlight the importance of having proper oxygen vacancies to facilitate the charge carrier transfer.…”

Section: Resultssupporting

confidence: 86%

Pt‐Induced Defects Curing on BiVO₄ Photoanodes for Near‐Threshold Charge Separation

Gao

Liu

Guo

et al. 2021

Advanced Energy Materials

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Photostability is one of the most essential properties for evaluating photoelectrochemical (PEC) water splitting performance on semiconductors. Herein, the oxygen‐deficiency conditions are applied to tune and activate BiVO4 photoanodes with a class of oxygen vacancies across the whole bulk material, and regulate the electronic occupancy of these states upon the charge carrier processes that determine PEC water oxidation activity. Through the experimental results and nonadiabatic molecular dynamics with time‐domain density functional theory calculations, the charge carrier lifetime can be influenced by the oxygen vacancies concentration on BiVO4, and the semiconductor can be flexibly photoactivated under oxygen‐sufficient and deficient atmospheres for enhancing the charge carrier density and photovoltage. The PEC performance of BiVO4 is further boosted by Pt doping, which exhibits a record photocurrent density of 5.45 mA cm–2 at 1.23 VRHE with solar conversion efficiency of 2.1% at 0.65 VRHE. The Pt can prevent the unnecessory charge recombination on the defected BiVO4, which also enhances the majority charge carrier density, resulting in one of the best charge separation efficiencies, close to 100%, among the steady‐state PEC performance for BiVO4. More importantly, the resulting Pt:BiVO4 presents long‐term stability over 50 h at 0.8 VRHE.

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Section: Resultssupporting

confidence: 86%

Pt‐Induced Defects Curing on BiVO₄ Photoanodes for Near‐Threshold Charge Separation

Gao

Liu

Guo

et al. 2021

Advanced Energy Materials

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“…The authors confirmed the reduction of surface recombination by PL spectra and the increase of carrier concentration, probably due to substituted oxygen. Xiao et al reported another doping method: gradient doping of Mg. [ 101 ] The authors confirmed the band‐edge shift by Mg doping, and they produced a band slope in Ta 3 N 5 bulk by making a gradient concentration of Mg. The gradient Mg‐doped Ta 3 N 5 showed a high photocurrent density of 8.5 mA cm −2 at 1.23 V versus RHE with a low onset potential of ≈0.4 V versus RHE, probably due to the internal electric field and reduced defect‐related recombination.…”

Section: Solutionmentioning

confidence: 77%

“…Cation doping (B, Mg, Sc, and Zr) has also been conducted for opaque Ta 3 N 5 photoanodes to shift the onset potential. [53][54][55][56]58,101] [58] The Ta 3 N 5 : MgþZr photoanode demonstrated a lower onset potential of 0.55 V versus RHE compared to that of Ta 3 N 5 , 0.8 V versus RHE with a photocurrent of 2.3 mA cm À2 at 1.23 V versus RHE (Figure 12a). Because the onset potentials of Ta 3 N 5 :Mg and Ta 3 N 5 :Zr were 0.70 and 0.57 V versus RHE, respectively, the authors concluded that Zr caused a negative shift in the onset potential (Figure 12a).…”

Section: Dopingmentioning

confidence: 99%

“…Cation doping (B, Mg, Sc, and Zr) has also been conducted for opaque Ta 3 N 5 photoanodes to shift the onset potential. [ 53–56,58,101 ] Seo et al developed Mg–Zr cosubstituted Ta 3 N 5 (Ta 3 N 5 :Mg+Zr) by using the precursor containing Ta 2 O 5 , Mg(NO 3 ) 2 ·6H 2 O, and ZrO(NO 3 ) 2 ·2H 2 O. [ 58 ] The Ta 3 N 5 :Mg+Zr photoanode demonstrated a lower onset potential of 0.55 V versus RHE compared to that of Ta 3 N 5 , 0.8 V versus RHE with a photocurrent of 2.3 mA cm −2 at 1.23 V versus RHE ( Figure a).…”

Section: Solutionmentioning

confidence: 99%

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Recent Developments in Visible‐Light‐Absorbing Semitransparent Photoanodes for Tandem Cells Driving Solar Water Splitting

Kawase

Higashi

Domen

et al. 2021

Adv Energy and Sustain Res

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The development of an efficient conversion system to transform solar energy into chemical energy, such as renewable hydrogen, is a promising way to overcome energy problems. Photoelectrochemical (PEC) water splitting is a promising means of obtaining renewable hydrogen directly from water utilizing sunlight. Recent reports have demonstrated that a PEC cell with a tandem configuration (tandem cell) has the potential to realize a high solar-to-hydrogen (STH) energy conversion efficiency by solar water splitting. However, there are still many obstacles to the development of practical and cost-effective tandem cells. In particular, development of efficient photoanodes for the oxygen evolution reaction (OER) is a prerequisite for improving the STH efficiency. Herein, recent progress in developing (semi)transparent photoanodes for the OER, such as Fe 2 O 3 , BiVO 4 , and Ta 3 N 5 , is described based on the topics of preparation methods, semiconductor properties, and PEC performance. In addition, the strategies for enhancing the STH efficiency of tandem cells consisting of (semi) transparent photoanodes conjugated with photovoltaic (PV)-based cathodes are summarized. This Review is expected to provide guidelines for the future development of tandem cells capable of highly efficient and stable water splitting.

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“…Tantalum nitride and tantalum oxynitrides have gained considerable attention in the photoelectrochemical community due to the favorable position of valence and conduction band for overall water splitting, and light absorption in the visible range. [ 43–45 ] By ALD, they can be prepared using H 2 O as an oxygen precursor to prepare Ta 2 O 5 , followed by annealing in ammonia (NH 3 ) to produce Ta 3 N 5 , [ 46 ] or directly by using NH 3 gas as nitride precursor in ALD. [ 47 ] TaO x N y has been achieved by the use of NH 3 as a nitride precursor and H 2 O as an oxygen precursor.…”

Section: Light Absorbermentioning

confidence: 99%

Atomic Layer Deposition for the Photoelectrochemical Applications

Pastukhova

Mavrič

2021

Adv Materials Inter

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Substantial progress has been made in the photoelectrochemical (PEC) field to understand the photoelectrode behavior, semiconductor‐electrolyte interface, and photocorrosion, enabling new photoelectrode architectures with higher photocurrent, reduced photovoltage losses, and longer lifetime. Nevertheless, for practical PEC applications additional efforts are still needed to optimize all components of the photoelectrodes, including the light absorbing semiconductors, the layers for charge extraction, charge transfer, corrosion protection, and catalysis. In this regard, atomic layer deposition (ALD) offers new opportunities due to the monolayer‐by‐monolayer deposition approach, allowing preparation of conformal films with precisely controlled thickness and composition. As the ALD instruments are becoming widely accessible, this review aims to make an overview of the applications for photoelectrodes fabrication. The deposition of semiconductors onto flat and nano‐textured substrates, the deposition of ultrathin interlayers to ease charge transport by energy band alignment and surface states passivation, the deposition of corrosion protection layers, and finally, the possibilities for high catalyst dispersion is presented.

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Band structure engineering and defect control of Ta3N5 for efficient photoelectrochemical water oxidation

Cited by 257 publications

References 47 publications

Pt‐Induced Defects Curing on BiVO₄ Photoanodes for Near‐Threshold Charge Separation

Pt‐Induced Defects Curing on BiVO₄ Photoanodes for Near‐Threshold Charge Separation

Recent Developments in Visible‐Light‐Absorbing Semitransparent Photoanodes for Tandem Cells Driving Solar Water Splitting

Atomic Layer Deposition for the Photoelectrochemical Applications

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Band structure engineering and defect control of Ta3N5 for efficient photoelectrochemical water oxidation

Cited by 257 publications

References 47 publications

Pt‐Induced Defects Curing on BiVO4 Photoanodes for Near‐Threshold Charge Separation

Pt‐Induced Defects Curing on BiVO4 Photoanodes for Near‐Threshold Charge Separation

Recent Developments in Visible‐Light‐Absorbing Semitransparent Photoanodes for Tandem Cells Driving Solar Water Splitting

Atomic Layer Deposition for the Photoelectrochemical Applications

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Product

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Pt‐Induced Defects Curing on BiVO₄ Photoanodes for Near‐Threshold Charge Separation

Pt‐Induced Defects Curing on BiVO₄ Photoanodes for Near‐Threshold Charge Separation