Photocatalytic hydrogen production using metal doped TiO2: A review of recent advances

Kumaravel, Vignesh; Mathew, Snehamol; Bartlett, John; Pillai, Suresh C.

doi:10.1016/j.apcatb.2018.11.080

Cited by 816 publications

(383 citation statements)

References 332 publications

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“…Titanium dioxide (TiO 2 ) has been identified as an interesting nanomaterial in the 21st century, owing to its promising physical, chemical and optical properties for numerous eco-friendly applications, such as water treatment, air purification, energy production and self-cleaning coatings using solar light [1]. The commercialisation of photocatalysis technology has gained significant interest in recent decades.…”

Section: Introductionmentioning

confidence: 99%

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

et al. 2020

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This work outlines an experimental and theoretical investigation of the effect of molybdenum (Mo) doping on the oxygen vacancy formation and photocatalytic activity of TiO 2 . Analytical techniques such as x-ray diffraction (XRD), Raman, x-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) were used to probe the anatase to rutile transition (ART), surface features and optical characteristics of Mo doped TiO 2 (Mo-TiO 2 ). XRD results showed that the ART was effectively impeded by 2 mol% Mo doping up to 750°C, producing 67% anatase and 33% rutile. Moreover, the crystal growth of TiO 2 was affected by Mo doping via its interaction with oxygen vacancies and the Ti-O bond. The formation of Ti-O-Mo and Mo-Ti-O bonds were confirmed by XPS results. Phonon confinement, lattice strain and non-stoichiometric defects were validated through the Raman analysis. DFT results showed that, after substitutional doping of Mo at a Ti site in anatase, the Mo oxidation state is Mo 6+ and empty Mo-s states emerge at the titania conduction band minimum. The empty Mo-d states overlap the anatase conduction band in the DOS plot. A large energy cost, comparable to that computed for pristine anatase, is required to reduce Mo-TiO 2 through oxygen vacancy formation. Mo 5+ and Ti 3+ are present after the oxygen vacancy formation and occupied states due to these reduced cations emerge in the energy gap of the titania host. PL studies revealed that the electron-hole recombination process in Mo-TiO 2 was exceptionally lower than that of TiO 2 anatase and rutile. This was ascribed to introduction of 5s gap states below the CB of TiO 2 by the Mo dopant. Moreover, the photo-generated charge carriers could easily be trapped and localised on the TiO 2 surface by Mo 6+ and Mo 5+ ions to improve the photocatalytic activity. coatings [8,9]. The most commonly existing crystalline polymorphs of TiO 2 are anatase, rutile and brookite [10][11][12]. Anatase is accepted to be the more active phase of TiO 2 and is preferred by the ceramic industries to fabricate light active antimicrobial indoor building materials such as ceramics, glass, tiles and sanitary surfaces [13,14]. This requires thermal stability of the anatase phase under typical ceramic processing conditions. TiO 2 anatase is mainly fabricated at low calcination temperatures (∼500°C) to prevent the anatase to rutile phase transition (ART) [15][16][17], which produces the less photo-active rutile phase. The photo-activity of anatase arises from its appropriate band edge positions, electron affinity, ionisation potential, and the long lifetime of charge carriers [10,12,18]. Moreover, transient photo-conductance analysis has revealed that the electron-hole recombination phenomena in anatase (101) phase is much slower compared to rutile (110), which is credited in part to the indirect band gap of anatase [11,19].The unit cells of anatase and rutile phases are composed of TiO 6 octahedra with titanium atoms at the centre and oxygen atoms at the vertices [20]. Both anatase and rutile have a t...

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Section: Introductionmentioning

confidence: 99%

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

et al. 2020

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“…Controlling charge generation and transfer process via doping is therefore a prime research field in heterogeneous photocatalysis. For example, doping based on metal oxides, transition‐metal chalcogenides,[10a] and graphitic conjugated materials remarkably enhances photocatalytic activity by increasing light adsorption, accelerating charge separation/transfer, and prolonging charge carrier lifetime. Among various doping strategies, transition‐metal doping is one of the most convenient and effective methods to modify the electronic structures of semiconductors as well as their textual properties .…”

Section: Introductionmentioning

confidence: 99%

Mo‐Doped ZnIn₂S₄ Flower‐Like Hollow Microspheres for Improved Visible Light‐Driven Hydrogen Evolution

2019

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Designing robust visible light‐driven photocatalysts in terms of the structure and component is an important way for achieving efficient solar hydrogen production. Herein, Mo‐doped ZnIn2S4 (M‐ZIS) flower‐like hollow microspheres assembled by ultrathin nanosheets are reported. The as‐prepared M‐ZIS samples achieve an enhanced H2 generation rate of 4.62 mmol g−1 h−1 under visible light, ten times higher than that of pristine ZIS. The 3D hollow microspheres structure assembled by nanosheets ensures sufficient light harvesting and exposure of more active sites. Meanwhile, the doping of Mo is propitious to regulate the chemical characteristic and electronic structure of ZIS in the merit of ameliorated hydrophilicity, extended light adsorption, accelerated transfer‐separation efficiency of charge carriers, as well as the reduced overpotential of H2 evolution. This model is put forward to obtain an in‐depth understanding of the role that both the 3D hollow hierarchical structure and doping atoms play in photocatalytic water splitting.

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“…The superoxide radical anions have strong oxidation ability, and can directly oxidize organic molecules (P) to form P + , or interact with OH – and H 2 O to form hydroxyl radicals ( • OH). • OH and • O 2 – have strong oxidizing properties, which can directly oxidize most organic pollutants into small inorganic molecules such as CO 2 and H 2 O …”

Section: Resultsmentioning

confidence: 99%

Pt Modified TiO₂_–_x/C Composites with Metal‐organic Frameworks as Precursors for Photodegradation of Organic Dye

Fan

2020

Zeitschrift anorg allge chemie

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A series of Pt modified TiO2–x/C composites with higher specific surface area were obtained by using a Zn‐Ti heterometallic metal‐organic framework (MOF) as the precursor. The photocatalytic activities of these composites were studied by methylene blue (MB) as a representative organic pollutant. The chemical composition and porosity of these composites can be adjusted by changing the pyrolysis temperature. Among them, the sample being pyrolyzed at 1000 °C (PTC‐P10) showed excellent photocatalytic performance, and its rate constant of degradation of MB was higher than that of ATC‐P10 (Ag modified TiO2–x/C composites) due to the rapid capture of electrons and the expansion of the photoresponse range caused by Pt modifying. This work represents a novel approach towards Pt modified TiO2–x/C composites as photocatalysts.

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Photocatalytic hydrogen production using metal doped TiO2: A review of recent advances

Cited by 816 publications

References 332 publications

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo‐Doped ZnIn₂S₄ Flower‐Like Hollow Microspheres for Improved Visible Light‐Driven Hydrogen Evolution

Pt Modified TiO₂_–_x/C Composites with Metal‐organic Frameworks as Precursors for Photodegradation of Organic Dye

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Photocatalytic hydrogen production using metal doped TiO2: A review of recent advances

Cited by 816 publications

References 332 publications

Mo doped TiO2: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo doped TiO2: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo‐Doped ZnIn2S4 Flower‐Like Hollow Microspheres for Improved Visible Light‐Driven Hydrogen Evolution

Pt Modified TiO2–x/C Composites with Metal‐organic Frameworks as Precursors for Photodegradation of Organic Dye

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Product

Resources

About

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo‐Doped ZnIn₂S₄ Flower‐Like Hollow Microspheres for Improved Visible Light‐Driven Hydrogen Evolution

Pt Modified TiO₂_–_x/C Composites with Metal‐organic Frameworks as Precursors for Photodegradation of Organic Dye