Experimental and theoretical investigation of WO  modification effects on the photocatalytic activity of titanium-substituted hydroxyapatite

Ishisone, Kana; Jiraborvornpongsa, Noppasint; Isobe, Toshihiro; Matsushita, Sachiko; Wakumura, Masato; Oshikiri, Mitsutake; Nakajima, Akira

doi:10.1016/j.apcatb.2019.118516

Cited by 13 publications

(11 citation statements)

References 48 publications

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“…The result suggests that the W valence number of modified WO x cluster is mostly 6+, which is consistent with XPS results we obtained earlier. 6) However, closer inspection ( Fig. S2) reveals that the white line peak shapes in the modified WO x cluster samples resembled those of WO 3 and Na 2 WO 4 •2H 2 O, but they are not exactly the same.…”

Section: Resultsmentioning

confidence: 93%

“…2. The amount of WO x cluster in each WO xmodified Ti-HAp sample was calculated from our earlier X-ray photoelectron spectroscopy (XPS) results, 6) showing that the amount of modified WO x cluster increased with repetition of the impregnationcalcination process. The WO x -modified Ti-HAps have a pre-edge peak area between WO 3 and Na 2 WO 4 •2H 2 O, which suggests the average structure of modified WO x cluster is between the WO 6 and WO 4 structures.…”

Section: Resultsmentioning

confidence: 99%

“…For this reason, we assume that WO x monolayer is modified on the Ti-HAp surface. A transmission electron microscope (TEM) image in our earlier study 6) shows the WO x cluster as nearly a circle. Therefore, for ease of exposition, we referred the bulk WO 3 crystal atomistic structure properties from the literature 12) and assumed that the WO x cluster has a squarelike structure.…”

Section: Wo X Cluster Local Structure Modified On a Ti-hap Surfacementioning

confidence: 85%

“…Very recently, we reported the synthesis of WO x clustermodified Ti-HAp, 6) with modified WO x clusters adhered onto a Ti-HAp surface through impregnationcalcination cycling using ammonium tungstate [(NH 4 ) 10 (H 2 W 12 O 42 )• 4H 2 O] as the W source. The modification increased the Ti-HAp photocatalytic activity for decomposition of gaseous IPA (2-propanol) under UV illumination.…”

Section: Introductionmentioning

confidence: 99%

“…Based on those findings, we discussed the validity of the WO x -modified Ti-HAp surface model, which was used in earlier reports of the literature. 6) 2. Experimental…”

Section: Introductionmentioning

confidence: 99%

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Local structure investigation of WOx cluster modified on titanium-substituted hydroxyapatite for promoting charge separation under UV illumination

Ishisone

Isobe

Matsushita

et al. 2020

J. Ceram. Soc. Japan

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The local structure of WO x clusters modified on Ti-doped hydroxyapatite (Ti-HAp) photocatalyst surface was analyzed using X-ray absorption fine structure (XAFS) measurements. W L 1-and L 3-edge X-ray absorption near-edge structure (XANES) spectra analyses revealed that WO x clusters include WO 4 and WO 6 structures and that WO 6 amounts increase concomitantly with increasing WO x cluster amounts. Results of analyses of W L 3edge extended X-ray absorption fine structure (EXAFS) spectra confirmed this finding, demonstrating that the average coordination number of W surrounded by O increases from 4 to 5 with increasing WO x cluster amount. The number of WOW bonds increased concomitantly with increasing amounts of modified WO x clusters, indicating the formation of WO x cluster aggregates. Assuming that two-dimensional WO x monolayer domains were formed and that the domain is square, the average WO x cluster structure was calculated as changing from a monomeric to a trimeric or tetrameric structure with increasing WO x loading amount. The cluster size obtained from the model is consistent with those found in our earlier experimental study. The cluster structure represented here demonstrated that the modified WO x clusters included a low coordination structure. Its electronic structure became different from that of doped W or bulk WO 3 and a suitable electron transition path from Ti 3d to W 5d was created, showing high photocatalytic activity.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Wo X Cluster Local Structure Modified On a Ti-hap Surfacementioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

“…Based on those findings, we discussed the validity of the WO x -modified Ti-HAp surface model, which was used in earlier reports of the literature. 6) 2. Experimental…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Local structure investigation of WOx cluster modified on titanium-substituted hydroxyapatite for promoting charge separation under UV illumination

Ishisone

Isobe

Matsushita

et al. 2020

J. Ceram. Soc. Japan

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Structure and Surface Study of Hydroxyapatite‐Based Materials

Costentin

Drouet

Salles

et al. 2022

Design and Applications of Hydroxyapatite‐Based Catalysts

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In addition to designing catalytic materials ever more active and selective, the emergence of new classes of greener catalysts remains very challenging. The apatite family system with hydroxyapatite (HA) structure appears as a good candidate for catalysis due to its ecocompatibility properties, its sorption ability toward organic molecules, and its tunable composition resulting into modulation of its surface properties. Depending on their mode of preparation, these inexpensive and environment-friendly apatitic calcium phosphates exhibit properties of relevance to catalysis, such as large surface area and various morphologies.However, most studies focused so far on the catalytic performance of these compounds, while the study of structure-reactivity relationships required for rationalized optimization remains rather limited. This chapter aims at providing tools to help understand the catalytic behavior of apatite compounds, giving details about their structure, surface properties, and reactivity; this will include both stoichiometric and nonstoichiometric compounds, sometimes biomimetic and potentially substituted. A special attention is dedicated to recent advances in the characterization of their structural properties (bulk and surface/interphase) that have a strong impact on their reactivity, through both experimental and computational approaches to study the mechanisms occurring in the structure or at the crystals surface, as well as thermodynamic and dynamical properties. Remaining characterization challenges for apatite-based catalysts will also be discussed. 1.an influence on the charges carried by the cation and on the related strength of the Ca-O interaction [127], which results in different adsorption properties with guest molecules. To go further, quantum calculations coupled with NMR (Nuclear Magnetic Resonance) resultsshowed the impact of the presence of OHions on the migration of Ca 2+ as well as the rotation of PO4 3groups [128]. In the hydroxyapatite structure, phosphate ions PO4 3are the largest components of the structure. As such, they provide a primary backbone via 3D compact-like piling, generating interstitial sites for the other ions of the structure. Metal cations such as Ca 2+ occupy two types of crystallographic sites, denoted Ca1 (4 sites per unit formula) and Ca2 (6 sites per unit formula), see Figure 2. Ca1 sites are localized along the trigonal axis with the coordinates (1/4, 3/4, 1/2) and (3/4, 1/4, 1/2), forming linear columns along the c-axis. Ca2 sites in contrast form equilateral triangles at z = 1/4 and z = 3/4 on the sixfold screw (senary) 63 axes. Adjacent Ca1 and Ca2 sites are linked through shared oxygen atoms from PO4 tetrahedra. Ca1 sites generate (distorted) polyhedra where the metal ion is in ninefold coordination, while in Ca2 sites it is in sevenfold coordination.The Ca2 triangles contribute to delimit so-called "apatitic channels" where ions such as OHare axially located (Figure 3) [116,120]. In calcium hydroxyapatite, the Ca2 triangular sites correspond to the narrow...

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Lattice Distortion Engineering over Ultrathin Monoclinic BiVO₄ Nanoflakes Triggering AQE up to 69.4% in Visible‐Light‐Driven Water Oxidation

Philo

Luo

et al. 2022

Adv Funct Materials

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An efficient water oxidation photocatalyst is imperative for the realization of artificial photosynthesis. Herein, a cooperative strategy is represented that enables 2D structure tailoring and lattice distortion engineering simultaneously over a BiVO4 photocatalyst for efficient visible‐light‐driven oxygen evolution reaction (OER). Specifically, the lattice distortion engineering is achieved through the introduction of a sodium (Na+) additive during the ion exchange process. Structural characterizations suggest the formation of ultrathin 2D monoclinic BiVO4 nanoflakes with shrank VO and elongated BiO bonds. Mechanistic investigations reveal the advantages of ultrathin 2D features for exposing more (010) active facets and shortening the required migration distance for charge carriers to reach the catalytic surface. More importantly, the lattice distortion effect is found to crucially govern the charge carrier dynamics and catalytic surface behavior of BiVO4 photocatalyst, endowing the optimized sample with an outstanding photocatalytic OER performance triggering up to 69.4% apparent quantum efficiency over Fe3+ sacrificial solution. These findings highlight the functional application of morphology and dimensional modification, as well as lattice distortion engineering in synthesizing superior monoclinic BiVO4 photocatalyst for efficient visible‐light‐driven water oxidation.

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Experimental and theoretical investigation of WO modification effects on the photocatalytic activity of titanium-substituted hydroxyapatite

Cited by 13 publications

References 48 publications

Local structure investigation of WO<i><sub>x</sub></i> cluster modified on titanium-substituted hydroxyapatite for promoting charge separation under UV illumination

Local structure investigation of WO<i><sub>x</sub></i> cluster modified on titanium-substituted hydroxyapatite for promoting charge separation under UV illumination

Structure and Surface Study of Hydroxyapatite‐Based Materials

Lattice Distortion Engineering over Ultrathin Monoclinic BiVO₄ Nanoflakes Triggering AQE up to 69.4% in Visible‐Light‐Driven Water Oxidation

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Experimental and theoretical investigation of WO modification effects on the photocatalytic activity of titanium-substituted hydroxyapatite

Cited by 13 publications

References 48 publications

Local structure investigation of WO<i><sub>x</sub></i> cluster modified on titanium-substituted hydroxyapatite for promoting charge separation under UV illumination

Local structure investigation of WO<i><sub>x</sub></i> cluster modified on titanium-substituted hydroxyapatite for promoting charge separation under UV illumination

Structure and Surface Study of Hydroxyapatite‐Based Materials

Lattice Distortion Engineering over Ultrathin Monoclinic BiVO4 Nanoflakes Triggering AQE up to 69.4% in Visible‐Light‐Driven Water Oxidation

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Product

Resources

About

Lattice Distortion Engineering over Ultrathin Monoclinic BiVO₄ Nanoflakes Triggering AQE up to 69.4% in Visible‐Light‐Driven Water Oxidation