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Colbeau‐Justin, Christophe; Kunst, M.; Huguenin, D.

doi:10.1023/a:1023905102094

Cited by 159 publications

(155 citation statements)

References 17 publications

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“…(i) It has a direct bandgap, which results in a shorter lifetime of the e-h pair than in anatase [15,16], and (ii) Rutile is usually a low surface area material.…”

Section: Electronic Transitions In Titaniamentioning

confidence: 99%

The Photocatalytic Window: Photo-Reforming of Organics and Water Splitting for Sustainable Hydrogen Production

et al. 2014

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Precious metal-titania materials make good catalysts for hydrogen production from a variety of organic substrates using sunlight. These substrates essentially act as reductants for water, by intercepting electrophilic oxygen species generated by electron-hole excitation resulting from photon absorption in the titania support. As a result, the hydrogen produced comes partly from water splitting and partly from dehydrogenation of the organic substrate. Why only precious metals work for the reaction is discussed, together with the mechanism of these reactions. The oxygenate substrates are decarbonylated to produce adsorbed CO, which is removed in the presence of light by the electrophilic oxygen as CO 2 , but the level of CO 2 detected is strongly affected by the amount of liquid water present, due to absorption and reaction to form carbonic acid. The possibilities for application of this technology in the domestic environment, the 'Photocatalytic Window' is considered.Keywords Photo-catalysis Á Photo-reforming Á Water splitting Á Hydrogen production Á Methanol Setting the SceneThe human race is in a period of fast transition in all sorts of aspects of life. Perhaps the most important of these is the changing energy scene. Because of the increase in population and increased industrialisation the most convenient forms of useable energy that are available in large quantity, fossil fuels, have been utilized for energy supply. These are firstly coal, used originally for driving steam generation for the new steam engines invented and widely introduced for manufacturing and transport in England from the late 18th century. Following from this came the widespread use of crude oil for transport, in the form of refined petroleum spirit, and in more recent times increasing use of gas powered electrical power generation and domestic combustion. As a result there has been an increase of CO 2 in the atmosphere-increasing from the geologically steady value of about 280 ppm, now just breaking the 400 ppm level, a 42 % increase. The source of these increases can be traced back to the original industrialisation of the early-mid 18th century. Figure 1 illustrates this in terms of the CO 2 level in the atmosphere, combined with a derivative which traces the start of this increase to the period just after the development of more efficient forms of steam engines for mechanical power generation see Ref. [1].The consequences of this geologically fast increase in CO 2 levels can be debated, but what is absolutely certain is that, as sentient beings, humans should not be playing with dice by abnormal perturbance of natural equilibrium, over a geologically fast timescale. The results are not likely to be positive for the planet, except in the sense that it might help reduce the human population.Thus there is an urgent need to stop the CO 2 increase and to find new sustainable ways of fuelling our future. Of course we have a number of successful technologies in Electronic supplementary material The online version of this article

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“…(i) It has a direct bandgap, which results in a shorter lifetime of the e-h pair than in anatase [15,16], and (ii) Rutile is usually a low surface area material.…”

Section: Electronic Transitions In Titaniamentioning

confidence: 99%

The Photocatalytic Window: Photo-Reforming of Organics and Water Splitting for Sustainable Hydrogen Production

et al. 2014

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“…42 TRMC measurements were carried out as previously described. 43 The incident microwaves were generated by a Gunn diode in the K a band (29)(30)(31). The experiments were performed at 30.0 GHz, frequency corresponding to the highest microwave power.…”

Section: Characterization Of the Solidsmentioning

confidence: 99%

“…43 This technique is based on the measurement of the change of the microwave power reflected by a sample, induced by its laser pulsed irradiation.…”

Section: Characterization Of the Solidsmentioning

confidence: 99%

Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration

Marcı̀

García‐López

Bellardita

et al. 2013

Phys. Chem. Chem. Phys.

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Catalytic and catalytic photo-assisted hydration of propene to form 2-propanol in gas-solid regime at atmospheric pressure and 85 1C were carried out by using a heteropolyacid (POM) supported on different oxides. Binary materials were prepared by impregnation of H 3 PW 12 O 40 on different commercial and home prepared supports (TiO 2 , SiO 2 , WO 3 , ZrO 2 , ZnO, Al 2 O 3 ). Some of the composites were active both for catalytic and catalytic photo-assisted reactions. The Keggin type POM was completely and partially degraded, when supported on ZnO and Al 2 O 3 , respectively, and these binary solids always resulted as inactive for both catalytic and catalytic photo-assisted reactions. The supported Keggin POM species played a key role both for the catalytic and the photo-assisted catalytic reactions, due to their strong acidity and ability to form strong oxidant species under UV irradiation, respectively. The contemporary presence of heat and UV light improved the activity of almost all POM supported materials. All materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM), diffuse reflectance spectroscopy (DRS), determination of the conduction and valence band energy by photovoltage measurements, Fourier transform infrared spectroscopy (FTIR), NH 3 -TPD experiments and time resolved microwave conductivity (TRMC).

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“…We have found previously that an EtOH concentration of 80 vol % was optimal for H 2 production in Au/TiO 2 systems, [14,52] there- ). This is rationalised because rutile has adirect band gap, whichresults in higher electron-hole recombination rates, [27,53,54] and rutile has larger particles izes and al ower specific surface area (Table 1). Largerp article sizes present longerd iffusion pathsf or chargem igration to the surface after photoexcitation, which increases recombination rates and decreases the catalytic activity.…”

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confidence: 99%

Heterojunction Synergies in Titania‐Supported Gold Photocatalysts: Implications for Solar Hydrogen Production

et al. 2015

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The mixed-phase nature of P25 TiO2 (85 % anatase/15 % rutile) plays a key role in the high H2 production rates shown by Au/P25 TiO2 photocatalysts in alcohol/water systems. However, a full understanding of the synergistic charge transfer mechanisms between the TiO2 polymorphs that drive the high rates is yet to be realised. Here, we deconstruct P25 TiO2 into its component phases, functionalise the phases with Au nanoparticles and explore charge transfer in Au/TiO2 systems using EPR spectroscopy. EPR spectroscopy and photocatalytic data provide direct evidence that electrons excited across the rutile band gap move to anatase lattice traps through interfacial surface sites, which decreases electron-hole pair recombination and increases charge carrier availability for photoreactions. In particular, three-phase interfacial sites between Au, anatase and rutile appear to be H2 evolution "hot spots". The results isolate the origin of high photocatalytic H2 production rates seen in Au/P25 TiO2 systems.

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Cited by 159 publications

References 17 publications

The Photocatalytic Window: Photo-Reforming of Organics and Water Splitting for Sustainable Hydrogen Production

The Photocatalytic Window: Photo-Reforming of Organics and Water Splitting for Sustainable Hydrogen Production

Keggin heteropolyacid H3PW12O40 supported on different oxides for catalytic and catalytic photo-assisted propene hydration

Heterojunction Synergies in Titania‐Supported Gold Photocatalysts: Implications for Solar Hydrogen Production

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