Electrochemical hydrogenation of mixed-phase TiO2 nanotube arrays enables remarkably enhanced photoelectrochemical water splitting performance

Liu, Jiaqin; Dai, Mengjia; Wu, Jian; Hu, Ying; Zhang, Qi; Cui, Jiewu; Wang, Yan; Tan, Hark Hoe

doi:10.1016/j.scib.2017.12.023

Cited by 35 publications

(22 citation statements)

References 44 publications

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“…The unpaired electrons of defect-associated species and vacancies in TiO 2 can be examined by the in situ EPR. As reported, the EPR signals of Ti 3+ defects, oxygen vacancies, and O 2– were located with g values of 1.960–1.990, 2.003, and 2.020, respectively. − As shown in Figure d, the weak peaks with a g value of 1.965 can be attributed to the existence of paramagnetic Ti 3+ species, while the strong peaks with a g value of 2.003 are assigned to V O , verifying the presence of oxygen vacancies associated with surface Ti 3+ . The lower intensity of surface metastable sites (surface Ti 3+ species) is possibly due to the easy oxidization by certain components in air (O 2 , H 2 O, etc.).…”

Section: Resultssupporting

confidence: 60%

Black Phosphorus Quantum Dot-Sensitized TiO₂ Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Zheng

Deng

et al. 2020

ACS Sustainable Chem. Eng.

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Photon absorption, charge separation and transportation, and charge-induced reactions at the active sites are the main crucial factors involved in the photoelectrochemical (PEC) water splitting. Herein, a combination of black phosphorus quantum dot (BPQD) sensitization and defect engineering strategies is employed to optimize the PEC performance of one-dimensional TiO2 nanotube array (NTA) photoanodes. The as-prepared TiO2–x /BP electrode exhibits a strong photocurrent density under simulated solar light irradiation, which is almost ∼3 times higher than that of bare TiO2. Specifically, the photocurrent increment of TiO2–x /BP is even larger than the sum of TiO2–x and TiO2/BP, verifying the synergistic effect of oxygen vacancies and BPQD sensitization. The maximum photoconversion efficiency of TiO2–x /BP is as high as 0.35%, while the value of TiO2 NTAs is calculated to be 0.13%. The results reveal that oxygen vacancies and BPQDs in the TiO2–x /BP composite not only facilitate the charge separation and transportation but also enhance the activity and quantity of reactive sites for water oxidation. The present strategy might open new routes to develop high-performance photoelectrodes for water splitting.

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Section: Resultssupporting

confidence: 60%

Black Phosphorus Quantum Dot-Sensitized TiO₂ Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Zheng

Deng

et al. 2020

ACS Sustainable Chem. Eng.

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“…Employing multi-phase TM(D)C co-catalysts on Si would be beneficial in maximizing PEC performance (Figure 14c). In case of metal oxide photocatalysts (for example, TiO 2 ), there are several reports that the mixture phase helps charge transfer, resulting in effective charge separation and suppressing the charge recombination [124]. However, whether the same mechanism is applied to TMD materials or not in terms of composition and phase structure needs further studies.…”

Section: Toward Multi-phase Tm(d)c Co-catalysts On Simentioning

confidence: 99%

Metal Chalcogenides on Silicon Photocathodes for Efficient Water Splitting: A Mini Overview

et al. 2019

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In the photoelectrochemical (PEC) water splitting (WS) reactions, a photon is absorbed by a semiconductor, generating electron-hole pairs which are transferred across the semiconductor/electrolyte interface to reduce or oxidize water into oxygen or hydrogen. Catalytic junctions are commonly combined with semiconductor absorbers, providing electrochemically active sites for charge transfer across the interface and increasing the surface band bending to improve the PEC performance. In this review, we focus on transition metal (di)chalcogenide [TM(D)C] catalysts in conjunction with silicon photoelectrode as Earth-abundant materials systems. Surprisingly, there is a limited number of reports in Si/TM(D)C for PEC WS in the literature. We provide almost a complete survey on both layered TMDC and non-layered transition metal dichalcogenides (TMC) co-catalysts on Si photoelectrodes, mainly photocathodes. The mechanisms of the photovoltaic power conversion of silicon devices are summarized with emphasis on the exact role of catalysts. Diverse approaches to the improved PEC performance and the proposed synergetic functions of catalysts on the underlying Si are reviewed. Atomic layer deposition of TM(D)C materials as a new methodology for directly growing them and its implication for low-temperature growth on defect chemistry are featured. The multi-phase TM(D)C overlayers on Si and the operation principles are highlighted. Finally, challenges and directions regarding future research for achieving the theoretical PEC performance of Si-based photoelectrodes are provided.

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“…11 , 29 , 30 However, a decrease in intensity and a slight blueshift of the characteristic peak at about 144 cm −1 were observed for the H 2 -TNT group compared with the air-TNT group, which was attributed to nonstoichiometry caused by the presence of oxygen vacancies on the crystal lattice of the H 2 -TNT group. 9 , 11 , 31…”

Section: Resultsmentioning

confidence: 99%

Immune response of macrophages on super-hydrophilic TiO₂ nanotube arrays

Gao

Wang

et al. 2020

J Biomater Appl

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Macrophages are attracting increasing attention in promoting implant-mediated osteogenesis by modulating the microenvironment of the implant site. Biomaterial surface properties including topography and wettability regulate macrophage responses to influence tissue repair. The objective of our present study was to investigate the effects of hydrogenated titanium dioxide nanotube surfaces on the immune response of macrophages in vitro. Hydrogenated titanium dioxide nanotubes (TNTs) were synthesized on Ti surfaces by anodic oxidation and hydrogenation to form super-hydrophilic nanotubular surfaces. Macrophages were seeded directly onto three substrates (hydrogenated TNTs (H2-TNTs), air-annealed TNTs, and commercially pure Ti substrates) and grown under standard or lipopolysaccharide-stimulated culture conditions. Cell proliferation and viability were evaluated by Cell Counting Kit-8 and live/dead staining at 24 and 48 h. Secretion and expression of pro- and anti-inflammatory cytokines were evaluated at 24 and 48 h to determine whether the surfaces elicited differential macrophage behaviors. Gene expression of the M1/M2 surface markers of macrophages was analyzed to assess the effect of the H2-TNT surface on macrophage polarization. The results showed that hydrogenation of the TNT surface resulted in a super-hydrophilic substrate, which exhibited markedly improved wettability attributable to the formation of oxygen vacancies in the nanotubes. The H2-TNT group induced a significantly lower macrophage proliferation rate and up-regulated anti-inflammatory cytokines (interleukin-10, bone morphogenetic protein-2, and transforming growth factor-β1) irrespective of lipopolysaccharide stimulation, while alleviating the secretion of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-6, nitric oxide, and macrophage chemotactic protein-1) induced by lipopolysaccharide. Moreover, the H2-TNT surface elicited up-regulated gene expression of M2 surface markers and down-regulation of M1 surface markers. We concluded that the hydrogenated TNT surface modulated macrophage immune responses, which could be useful in accelerating inflammation resolution and facilitating tissue repair.

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Electrochemical hydrogenation of mixed-phase TiO2 nanotube arrays enables remarkably enhanced photoelectrochemical water splitting performance

Cited by 35 publications

References 44 publications

Black Phosphorus Quantum Dot-Sensitized TiO₂ Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Black Phosphorus Quantum Dot-Sensitized TiO₂ Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Metal Chalcogenides on Silicon Photocathodes for Efficient Water Splitting: A Mini Overview

Immune response of macrophages on super-hydrophilic TiO₂ nanotube arrays

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Electrochemical hydrogenation of mixed-phase TiO2 nanotube arrays enables remarkably enhanced photoelectrochemical water splitting performance

Cited by 35 publications

References 44 publications

Black Phosphorus Quantum Dot-Sensitized TiO2 Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Black Phosphorus Quantum Dot-Sensitized TiO2 Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Metal Chalcogenides on Silicon Photocathodes for Efficient Water Splitting: A Mini Overview

Immune response of macrophages on super-hydrophilic TiO2 nanotube arrays

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Resources

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Black Phosphorus Quantum Dot-Sensitized TiO₂ Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Black Phosphorus Quantum Dot-Sensitized TiO₂ Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Immune response of macrophages on super-hydrophilic TiO₂ nanotube arrays