WO2006077169A1 - Measuring device and measuring method for measuring photocatalytic activity of a photocatalytic layer - Google Patents

Measuring device and measuring method for measuring photocatalytic activity of a photocatalytic layer Download PDF

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Publication number
WO2006077169A1
WO2006077169A1 PCT/EP2006/000679 EP2006000679W WO2006077169A1 WO 2006077169 A1 WO2006077169 A1 WO 2006077169A1 EP 2006000679 W EP2006000679 W EP 2006000679W WO 2006077169 A1 WO2006077169 A1 WO 2006077169A1
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WIPO (PCT)
Prior art keywords
measuring
indicator
photocatalytic
photocatalytic layer
radiation source
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PCT/EP2006/000679
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German (de)
French (fr)
Inventor
Armin Zastrow
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Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
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Publication of WO2006077169A1 publication Critical patent/WO2006077169A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/8422—Investigating thin films, e.g. matrix isolation method
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N2021/7796—Special mountings, packaging of indicators

Definitions

  • the invention relates to a measuring device for measuring the photocatalytic activity of an irradiated photocatalytic layer and to a method by which the photocatalytic activity of a photocatalytic layer can be measured.
  • photocatalytic effect has become increasingly important in recent years, not only in research but also in the industrial sector.
  • windows are already being sold, which are provided with a special coating which has photocatalytic activity.
  • the photocatalytic activity of this special coating causes organic substances that settle on their surface to be accelerated. That with such a coating provided window thus cleans itself in a sense.
  • Another effect of photocatalytic activity is that the contact angle of water deposited on the photocatalytic layer is greatly reduced. The formation of drops on such a layer, which is particularly undesirable in a window pane, is suppressed by this effect.
  • photocatalytic materials can be used for air and gas cleaning, for water purification, for disinfection and sterilization, and for the surface cleaning just described, to name a few fields of application.
  • the known methods require - in situ characterization - the preparation of the sample on site, which can be cumbersome and time consuming, sometimes even impossible. Associated with this is the entrainment of toxic or harmful chemicals such as dyes, solvents, etc., and their use in unsuitable environments.
  • a further disadvantage of the known methods for evaluating the photocatalytic activity of a photocatalytic layer is revealed when photocatalyst surfaces having very different properties have to be evaluated.
  • this requires different application techniques and preparation of the indicators and the surfaces, on the other hand, the properties of the indicators themselves depend on the surface.
  • the measured values obtained, for example, by spectroscopy with regard to the degradation of the indicator can strongly depend on which solid-state surface the indicator is applied.
  • This object is achieved by a measuring device for measuring photocatalytic activity and a method for measuring the photocatalytic activity according to the independent claims.
  • the invention discloses a measuring device for measuring the photocatalytic activity of a photocatalytic layer irradiated with a radiation source, wherein the measuring device comprises a measuring probe with a measuring head, and the measuring head is provided with an indicator which reacts to the photocatalytic activity of the photocatalytic layer, which is used to measure the photocatalytic activity can be positioned at a distance from the photocatalytic layer.
  • the present invention thus differs from the prior art by a significant point: in the prior art, a surface application of the indicator is provided on the photocatalytic layer to be measured. In the present invention, however, the indicator is added to a measuring device detached from the sample to be examined. As a result, the above-mentioned disadvantages of the prior art, such as the
  • the measuring head equipped with the indicator is brought into sufficient proximity of the photocatalytic layer.
  • a flat-bottomed tion of the indicator and the photocatalytic layer is, in contrast to the prior art, not provided. It is possible to separately prepare the measuring device with the indicator and then to use it at a desired place of use.
  • the evaluation of the indicator for the purpose of determining the photocatalytic activity of the photocatalytic layer has likewise become independent of the place of use with the present invention. For example, after the indicator contained in the measuring device has been exposed for a certain time and in a certain proximity of the photocatalytically active layer, the measuring device can be removed and the indicator can be evaluated at any location.
  • An advantageous development of the invention provides that the indicator is applied to a substrate.
  • the indicator holds the indicator in a stable position through the substrate. This is particularly advantageous for very thin indicator layers.
  • a substrate is particularly suitable for the application of indicators in the liquid and gaseous phase.
  • the use of a substrate allows the separate preparation of the indicator: For example, one could remove the substrate of the measuring device, clean it in a first device, equip it with a new indicator layer in a second device, and then finally back in integrate the measuring device.
  • the substrate may also be designed to cover or enclose the indicator. It is also possible that the substrate is impregnated with the indicator, dyed or mixed, as well as a solution of the indicator in the substrate is possible. However, it should be noted that the properties of the substrate are adapted to the radiation source.
  • a further advantageous development of the invention provides that the substrate is glass or a film.
  • an indicator to soak or coloring an adhesive strip which represents the substrate.
  • an adhesive strip which represents the substrate.
  • Such a prepared adhesive strip taken by itself, constitutes a measuring device according to the invention for measuring photocatalytic activity. Due to the simplicity of such an adhesive strip, there is a high application potential. For example, if one wants the photocatalytic activity of windows, tiles, etc, provided with a photocatalytic layer. measure, sticks the prepared adhesive strip for a certain time on the photocatalytic layer to be examined, and then evaluates the tape easily in an external device.
  • the alternative to stick the tape on the measuring head could, for example, be equipped with a glass window for this purpose.
  • a further advantageous development of the invention provides that the measuring probe has a spacer.
  • the spacer has the task of keeping the indicator and the photocatalyst at a defined distance. In particular, this supports the reproducibility and the accuracy of the measurements. Furthermore, the spacer can advantageously be designed as a sealing ring. By sealing the space between the indicator and the photocatalyst, an escape of the radicals produced by the photocatalysis on the surface of the photocatalyst and necessary for the transmission of the photocatalytic effect to the indicator is suppressed.
  • the indicator is an organic dye, such as, for example, methylene blue, or consists of long-chain aliphatic molecules, such as, for example, oleic acid or stearic acid, or of highly fluorescent and highly stable perylene derivatives.
  • a further advantageous development of the invention provides that the radiation source is integrated in the measuring probe.
  • the radiation source is integrated in the measuring device, then no external radiation source must be made available. In the sense of a handy measuring device, the use of LEDs or the use of fiber optic cables is particularly suitable.
  • the radiation source can be placed behind the indicator and, if used, the substrate, whereby the photocatalytic layer is irradiated by the indicator and, if used, by the substrate.
  • this type of use of the radiation source necessitates the use of an indicator and a substrate, which are influenced to a very small extent by the radiation source.
  • a further advantageous development of the invention provides that the radiation source generates light in the UVA range.
  • the appropriate spectral range of the beams generated by the radiation source depends on the physical properties of the photocatalytic layer.
  • Light in the UVA range is particularly suitable for the photocatalyst titanium dioxide or for photocatalysts with a similar band gap, such as titanium dioxide doped with nitrogen, tungsten or niobium iron, as well as for the photocatalysts zinc oxide and tin oxide.
  • the radiation source must be adapted accordingly. Accordingly, it may be advantageous to use radiation sources that operate in the UVB range, or even in the visible range. Associated with this, if necessary, is the adaptation of used optical components.
  • a further advantageous development of the invention provides that a detector for measuring the degradation of the indicator is integrated in the measuring probe by means of absorption measurements / spectroscopy, in particular infrared absorption measurements / spectroscopy, UV-VIS measurements / spectroscopy or fluorescence measurements / spectroscopy.
  • a further advantageous development of the invention provides that a detection radiation source for irradiating the indicator for measuring the degradation of the indicator by means of absorption measurements / spectroscopy, in particular infrared absorption measurements / spectroscopy, UV-VIS measurements / spectroscopy or fluorescence measurements / Spectroscopy is integrated in the probe.
  • the indicator is irradiated by the detection radiation source.
  • the detector records the response of the irradiated indicator. If the indicator changes its physical properties due to its interaction with the active photocatalyst, the detector registers this in a changing response function of the indicator. In particular, fluorescence measurements allow the detection of the least changes in the properties of the indicator.
  • a further advantageous development of the invention provides that a device for measuring the hydrophilicity is integrated in the measuring probe.
  • a drop of a strongly polar liquid changes its properties on a photocatalytically active layer.
  • the contact angle which is high at the beginning is greatly reduced in a few minutes owing to the influence of the photocatalytic activity in a short time, for example in the case of water on titanium dioxide in solar UVA light in a few minutes. graces.
  • Contact angle measurements, but also the determination of the droplet size, in particular the droplet radius allow an evaluation of the hydrophilicity and thus also an evaluation of the photocatalytic activity of the photocatalytic layer.
  • the determination of the drop radius should be emphasized, which can be integrated with simple means in the measuring device according to the invention.
  • a further advantageous development of the invention provides that a measuring electronics and / or a power supply of the radiation sources is integrated in the measuring probe.
  • the last-mentioned advantageous developments have the goal of a measuring device which is as independent as possible of other devices. This plays a role in particular for the use of such a measuring device, for example in outdoor use. Furthermore, it was also possible to integrate display elements in the measuring probe, which allow immediate reading of the photocatalytic activity. Furthermore, the measuring device can also be equipped with suitable interfaces for connecting the measuring device to a PC.
  • the invention further discloses a method for measuring the photocatalytic activity of a photocatalytic layer irradiated with a radiation source, comprising the step of positioning an indicator, which reacts to the photocatalytic activity, for measuring the photocatalytic activity at a small distance from the photocatalytic layer.
  • the indicator becomes direct and applied flat on the photocatalytic layer to be examined. Associated with this are problems which may arise during the preparation of the indicator, which may arise during the measurement of the indicator and which may arise when the indicator is removed from the photocatalytic layer. These problems are avoided by the step according to the invention that an indicator which reacts to the photocatalytic activity for measuring the photocatalytic activity is positioned at a small distance from the photocatalytic layer.
  • a large-area connection of indicator and photocatalytic layer to be examined does not have to be present for an evaluation of the photocatalytic activity of the photocatalytic layer: If the indicator is located at a small distance from the photocatalytic layer, it is likewise possible to reliably determine the photocatalytic activity of the photocatalytic layer to eat . In this case, however, punctual touches of indicator and photocatalytic layer should not be excluded.
  • the method according to the invention permits the non-destructive measurement of the photocatalytic activity at arbitrary locations.
  • short distance is to be understood as meaning that the indicator and the photocatalytic layer do not touch, the maximum distance being given by a necessary minimum reaction of the indicator (if the distance between the indicator photocatalytic layer is too great, the influence of the active layer to be too low on the indicator for meaningful detection). For example, distances of several millimeters are possible. However, it is also dependent on the type of construction.
  • the radiation source irradiates the photocatalytic layer through the indicator and / or irradiates the photocatalytic layer from the side facing away from the indicator and / or the photocatalytic layer through which it is located between the indicator and the photocatalytic layer Slit irradiated.
  • the inventive method a flexible use of the radiation source.
  • the back irradiation of the photocatalytic layer through the window pane may be advantageous.
  • it is desired to investigate the photocatalytic activity of a photocatalytic layer on tiles or sheets it is advisable to irradiate the photocatalytic layer through the indicator. If both of these cases are not possible, there is still the possibility of exposing the photocatalytic layer to radiation between the indicator and the photocatalytic layer
  • a further advantageous development of the method provides that the photocatalytic layer is irradiated by the radiation source prior to the measurement of the photocatalytic activity and / or that the photocatalytic layer is irradiated by the radiation source during the measurement of the photocatalytic activity.
  • a further advantageous development of the method provides that during the measurement of the photocatalytic activity there is a spacer between the measuring device and the photocatalytic layer.
  • the spacer has to keep the purpose indicator and 'photo- tokatalytician layer in a defined distance. Furthermore, the spacer may be designed as a sealing ring. This counteracts the escape of the radicals generated by the photocatalysis and necessary for the transfer of the photocatalytic effect from the gap between the indicator and the photocatalytic layer. This increases the reproducibility and accuracy of the measurements.
  • the spacer may be located on the measuring device. Likewise, this spacer may be attached to the photocatalytic layer to be examined. However, the spacer may also be a single object, which is used analogously in the method according to the invention.
  • a further advantageous development of the method provides that a measuring device according to claims 1 to 11 is used as measuring device.
  • FIG. 1 shows a measuring device according to the invention for measuring the photocatalytic activity of a photocatalytic layer irradiated with a radiation source
  • FIG. 1 shows a measuring device for measuring the photocatalytic activity of a photocatalytic layer irradiated with a radiation source.
  • the measuring device contains a measuring probe 1.
  • the measuring head of this measuring probe 1 is formed by an indicator 5 which is located on a substrate 6.
  • the indicator consists of methylene blue, an organic dye.
  • the substrate on which the indicator 5 is located is a UVA translucent glass plate.
  • the measuring device 1 is equipped with a radiation source 2.
  • the radiation source 2 in this case is an LED which operates in the UVA range. It is placed inside the measuring device 1 behind the indicator 5 and the substrate 6. This makes it possible to irradiate the surface located in front of the measuring head, in particular in front of the indicator 5.
  • a detection radiation source 9 and a detector 8 are integrated in the measuring device 1.
  • the detection radiation source is likewise embodied as an LED in this exemplary embodiment and operates in the red region of the visible spectrum. It is therefore suitable to stimulate the indicator 5 to fluorescence. Accordingly, the detection irradiation source 9 is positioned near the indicator 5, to irradiate this as large as possible. If the fluorescence properties of the indicator 5 change, this is detected via the detector 8. Accordingly, this detector 8 is likewise located in the vicinity of the indicator layer 5.
  • a detection radiation source instead of an LED in the red area, a detection radiation source can be used which operates in the VIS range or in the UV-VIS range.
  • the power supply for operating the radiation sources and the detector as well as the measuring electronics necessary for the operation of the measuring device are accommodated in the rear area 10 of the measuring device, lying on the other side of the measuring head. Not shown in the drawing are display elements which are also integrated in area 10. Via a data cable 11, the measuring device 1 is connected to a PC, not shown here.
  • the measuring device 1 is directed with its measuring head onto a photocatalytic layer 3.
  • the photocatalytic layer 3 consists of the photocatalyst titanium dioxide.
  • the photocatalytic layer 3 forms the surface of a window pane 4.
  • the distance between the photocatalytic layer 3 and the indicator 5 is predetermined by a spacer 7.
  • This spacer 7 is located directly on the measuring device 1. Through it, the indicator and the photocatalytic layer are held in parallel in this embodiment, a distance of 0.5 mm. possible But leh are also larger distances of up to several millimeters.
  • the spacer is designed as a sealing ring, whereby the air exchange between the gap between indicator 5 and photocatalytic layer 3 is prevented with the outside.
  • the photocatalytic activity of the photocatalytic layer 3 can be measured by the method according to the invention. This will be shown with reference to an embodiment.
  • the measuring probe 1 with the prepared indicator 5 is brought to the photocatalytic layer 3 to be examined so that the indicator 5 and the photocatalytic layer are at a small distance. This situation is shown in FIG. 1.
  • FIG. 1 shows the situation in which the radiation source 2 is arranged behind the indicator 5: the photocatalytic layer 3 is irradiated through the indicator 5.
  • the indicator 5 and the photocatalytic layer are kept at a defined distance by means of a spacer 7.
  • the spacer is located on the probe.
  • the photocatalytic layer 3 is activated by irradiation by means of the radiation source 2.
  • the photocatalytic layer 3 can now be activated before the measurement of the photocatalytic activity, or else the photocatalytic layer 3 is activated simultaneously with the measurement of the photocatalytic activity, as should be assumed for this exemplary embodiment.
  • the photocatalytic activity of the photocatalytic layer 3 changes the absorption and fluorescence properties of the indicator 5. These changes in the indicator 5 are registered via absorption or fluorescence measurements / spectroscopy by means of the detection radiation source 9 and the detector 8.
  • the change in the absorption or fluorescence properties of the indicator 5 provides information about the photocatalytic activity of the photocatalytic layer 3, which can be read off on the display element (not shown here in detail in FIG. 1) or on the PC.
  • the measuring device shown in Figure 1 is limited in its presentation to a measurement of the photocatalytic effect by means of spectroscopy. However, this should not exclude that a device for measuring the hydrophilicity of the photocatalyst in the probe 1 can be supplemented, or even completely replaced the necessary components for spectroscopy.
  • a device for measuring the hydrophilicity of the photocatalyst in the probe 1 can be supplemented, or even completely replaced the necessary components for spectroscopy.
  • Such a device could include, for example, a video system. Now bring a defined drop of water on the surface of the Photocatalyst 3, it could be observed with the video system, the temporal behavior of the water droplet. In this regard, for example, it is advisable to observe the drop radius or the contact angle. The temporal behavior of the water droplet in turn provides information about the activity of the photocatalyst 3.
  • FIG. 2 shows a measuring device according to the prior art.
  • Indicator 5 is applied to the surface of the photocatalyst in direct and planar contact with the photocatalyst.
  • a radiation source 2 is positioned.
  • the photocatalyst 3 is activated.
  • the indicator 5 is degraded. This degradation is detectable for example by means of absorption spectroscopy.

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Abstract

The invention relates to a device and method for measuring photocatalytic activity of a photocatalytic layer irradiated by a source of radiation. The device contains a measuring probe (1) with a measuring head, the measuring head being equipped with an indicator (5) that reacts to the photocatalytic activity of the photocatalytic layer (3). The inventive method provides that an indicator (5), which reacts to the photocatalytic activity and which serves to measure the photocatalytic activity, is positioned at a short distance from the photocatalytic layer (3). The inventive device and method make it possible to measure photocatalytic layers in a non-destructive and defined manner.

Description

Messvorrichtung und Messverfahren zum Messen photokatalytischer Aktivität einer photo- katalytischen Schicht Measuring device and measuring method for measuring the photocatalytic activity of a photocatalytic layer
Die Erfindung betrifft eine Messvorrichtung zum Messen photokatalytischer Aktivität einer bestrahlten photokatalytischen Schicht und ein Verfahren, mit dem die photokatalytische Aktivität einer photokatalytischen Schicht gemessen werden kann .The invention relates to a measuring device for measuring the photocatalytic activity of an irradiated photocatalytic layer and to a method by which the photocatalytic activity of a photocatalytic layer can be measured.
Der photokatalytische Effekt hat in den vergangenen Jahren zunehmende Bedeutung erlangt, nicht nur in der Forschung, sondern auch im industriellen Bereich . Auf dem Markt werden beispielsweise schon Fenster ver- trieben, die mit einer speziellen Beschichtung versehen sind, die photokatalytische Aktivität besitzt . Die photokatalytische Aktivität dieser speziellen Beschichtung bewirkt , dass organische Substanzen, die sich auf der deren Oberfläche ablagern, beschleunigt abgebaut werden . Das mit solch einer Beschichtung versehene Fenster reinigt sich somit in gewisser Weise selbst . Ein weiterer Effekt der photokatalytischen Aktivität ist , dass der Kontaktwinkel von Wasser, das sich auf der photokatalytischen Schicht abgelagert hat, stark reduziert wird. Das Bilden von Tropfen auf einer solchen Schicht , das insbesondere bei einer Fensterscheibe unerwünscht ist, wird durch diesen Effekt unterdrückt . Des Weiteren können photokatalyti- sche Materialien zur Luft- und Gasreinigung, zur Was- serreinigung, zur Desinfektion und Sterilisation, und zur eben beschriebenen Oberflächenreinigung eingesetzt werden, um einige Anwendungsgebiete zu nennen .The photocatalytic effect has become increasingly important in recent years, not only in research but also in the industrial sector. On the market, for example, windows are already being sold, which are provided with a special coating which has photocatalytic activity. The photocatalytic activity of this special coating causes organic substances that settle on their surface to be accelerated. That with such a coating provided window thus cleans itself in a sense. Another effect of photocatalytic activity is that the contact angle of water deposited on the photocatalytic layer is greatly reduced. The formation of drops on such a layer, which is particularly undesirable in a window pane, is suppressed by this effect. Furthermore, photocatalytic materials can be used for air and gas cleaning, for water purification, for disinfection and sterilization, and for the surface cleaning just described, to name a few fields of application.
Der zunehmende Gebrauch von Photokatalysatoren, ins- besondere bei industriell hergestellten Produkten, erfordert Messtechniken, die es erlauben, die photo- katalytische Aktivität von photokatalytischen Schichten zuverlässig zu bewerten .The increasing use of photocatalysts, especially in industrially manufactured products, requires measurement techniques that allow reliable evaluation of the photocatalytic activity of photocatalytic layers.
Um die photokatalytische Aktivität einer photokatalytischen Schicht zu bewerten ist bekannt, als Indikator für die photokatalytische Aktivität wirkendes organisches Material in Form von Gasen, Flüssigkeiten oder Festkörpern in definierter Weise mit der aktiven Oberfläche der photokatalytischen Schicht in direkten, flächigen Kontakt zu bringen . Die photokatalytische Schicht wird in der Folge in der Regel mit UVA- Licht bestrahlt, wodurch die photokatalytische Schicht aktiviert wird. Der durch die photokatalyti- sehe Aktivität bewirkte Abbau des Indikators oder aber der Aufbau von Reaktionsprodukten wird nachgewiesen . Hierfür werden insbesondere spektroskopische Verfahren verwendet . Ein derartiges Verfahren wird beispielsweise in der JP 2002228589 A offenbart .In order to evaluate the photocatalytic activity of a photocatalytic layer, it is known to bring organic material in the form of gases, liquids or solids, which act as an indicator for the photocatalytic activity, in direct, planar contact with the active surface of the photocatalytic layer in a defined manner. As a result, the photocatalytic layer is usually irradiated with UVA light, whereby the photocatalytic layer is activated. The degradation of the indicator caused by the photocatalytic activity or the formation of reaction products is demonstrated. For this purpose, in particular spectroscopic methods are used. Such a method is disclosed, for example, in JP 2002228589 A.
Dieser Stand der Technik hat einige wesentliche Nachteile : Nicht immer können die direkt auf die Oberfläche des Photokatalysators aufgebrachten Indikatoren rückstandsfrei entfernt werden . Die Messmethode ist also nicht zerstörungsfrei .This prior art has some essentials Disadvantages: The indicators applied directly to the surface of the photocatalyst can not always be removed without residue. The measuring method is therefore not non-destructive.
Des Weiteren erfordern die bekannten Methoden - bei in-situ-Charakterisierung - die Präparation der Messprobe vor Ort, was umständlich und zeitaufwendig, gelegentlich sogar unmöglich sein kann . Damit verbunden ist ein Mitführen von zum Teil giftigen oder gesundheitsschädlichen Chemikalien, wie Farbstoffen, Lösungsmitteln usw. und ihre Anwendung in dafür ungeeigneter Umgebung .Furthermore, the known methods require - in situ characterization - the preparation of the sample on site, which can be cumbersome and time consuming, sometimes even impossible. Associated with this is the entrainment of toxic or harmful chemicals such as dyes, solvents, etc., and their use in unsuitable environments.
Ein weiterer Nachteil der bekannten Methoden zur Bewertung der photokatalytischen Aktivität einer photo- katalytischen Schicht offenbart sich, wenn Photokatalysatoroberflächen mit ganz verschiedenen Eigenschaften bewertet werden müssen . Dies erfordert einerseits unterschiedliche Applikationstechniken und Vorbereitung der Indikatoren und der Oberflächen, zum anderen hängen die Eigenschaften der Indikatoren selbst von der Oberfläche ab . So können die beispielsweise durch Spektroskopie gewonnenen Messwerte bezüglich des Ab- baus des Indikators stark davon abhängen, auf welcher Festkörperoberfläche der Indikator aufgebracht ist .A further disadvantage of the known methods for evaluating the photocatalytic activity of a photocatalytic layer is revealed when photocatalyst surfaces having very different properties have to be evaluated. On the one hand, this requires different application techniques and preparation of the indicators and the surfaces, on the other hand, the properties of the indicators themselves depend on the surface. Thus, the measured values obtained, for example, by spectroscopy with regard to the degradation of the indicator can strongly depend on which solid-state surface the indicator is applied.
Aufgabe der vorliegenden Erfindung ist es deswegen, eine Messvorrichtung und ein Verfahren zur Bewertung der photokatalytischen Aktivität einer photokatalytischen Schicht zu schaffen, die benannte Nachteile des Stands der Technik vermeidet, die insbesondere eine aufwendige Präparation der zu messenden photokatalytischen Schicht unnötig macht, und damit flexibel einsetzbar ist . Diese Aufgabe wird durch eine Messvorrichtung zur Messung photokatalytischer Aktivität und ein Verfahren zum Messen der photokatalytischen Aktivität nach den unabhängigen Ansprüchen gelöst .It is therefore an object of the present invention to provide a measuring device and a method for evaluating the photocatalytic activity of a photocatalytic layer, which avoids the named disadvantages of the prior art, which in particular makes a complicated preparation of the photocatalytic layer to be measured unnecessary, and thus can be used flexibly is. This object is achieved by a measuring device for measuring photocatalytic activity and a method for measuring the photocatalytic activity according to the independent claims.
Die Erfindung offenbart eine Messvorrichtung zum Messen photokatalytischer Aktivität einer mit einer Strahlungsquelle bestrahlten photokatalytischen Schicht, wobei die Messvorrichtung eine Messsonde mit einem Messkopf enthält, und der Messkopf mit einem auf die photokatalytische Aktivität der photokatalytischen Schicht reagierenden Indikator ausgestattet ist, der zur Messung der photokatalytischen Aktivität mit Abstand zur photokatalytischen Schicht positio- nierbar ist .The invention discloses a measuring device for measuring the photocatalytic activity of a photocatalytic layer irradiated with a radiation source, wherein the measuring device comprises a measuring probe with a measuring head, and the measuring head is provided with an indicator which reacts to the photocatalytic activity of the photocatalytic layer, which is used to measure the photocatalytic activity can be positioned at a distance from the photocatalytic layer.
Die vorliegende Erfindung unterscheidet sich somit von dem Stand der Technik um einen wesentlichen Punkt : nach dem Stand der Technik ist ein flächiges Auftragen des Indikators auf die zu messende photokatalytische Schicht vorgesehen . In der vorliegenden Erfindung ist der Indikator aber einer von der zu untersuchenden Probe losgelösten Messvorrichtung zugeschlagen. Dadurch werden die weiter oben schon er- wähnten Nachteile des Standes der Technik, wie dieThe present invention thus differs from the prior art by a significant point: in the prior art, a surface application of the indicator is provided on the photocatalytic layer to be measured. In the present invention, however, the indicator is added to a measuring device detached from the sample to be examined. As a result, the above-mentioned disadvantages of the prior art, such as the
Probleme beim Entfernen des Indikators , wie die komplizierte Präparation der Messprobe vor Ort, sowie auch die Probleme, die bei einer Messung von Photokatalysatoroberflächen mit verschiedenen Eigenschaften anfallen, vermieden .Problems with removing the indicator, such as the complicated preparation of the test sample on site, as well as the problems that arise when measuring photocatalyst surfaces with different properties avoided.
Um die photokatalytische Aktivität einer photokatalytischen Schicht mit einer erfindungsgemäßen Vorrichtung bewerten zu können, bringt man den mit dem Indi- kator ausgestatteten Messkopf in ausreichende Nähe der photokatalytischen Schicht . Eine flächige Beruh- rung des Indikators und der photokatalytischen Schicht ist, im Gegensatz zum Stand der Technik, nicht vorgesehen . Es ist möglich, die Messvorrichtung mit dem Indikator gesondert zu präparieren, und dann an einem gewünschten Einsatzort zu verwenden .In order to be able to evaluate the photocatalytic activity of a photocatalytic layer with a device according to the invention, the measuring head equipped with the indicator is brought into sufficient proximity of the photocatalytic layer. A flat-bottomed tion of the indicator and the photocatalytic layer is, in contrast to the prior art, not provided. It is possible to separately prepare the measuring device with the indicator and then to use it at a desired place of use.
Die Auswertung des Indikators zwecks Bestimmung der photokatalytischen Aktivität der photokatalytischen Schicht ist mit der vorliegenden Erfindung ebenfalls vom Einsatzort unabhängig geworden . Nachdem beispielsweise der in der Messvorrichtung enthaltene Indikator eine gewisse Zeit und in einer gewissen Nähe der photokatalytisch aktiven Schicht ausgesetzt wurde, kann die Messvorrichtung entfernt werden, und der Indikator an einem beliebigen Ort ausgewertet werden.The evaluation of the indicator for the purpose of determining the photocatalytic activity of the photocatalytic layer has likewise become independent of the place of use with the present invention. For example, after the indicator contained in the measuring device has been exposed for a certain time and in a certain proximity of the photocatalytically active layer, the measuring device can be removed and the indicator can be evaluated at any location.
Vorteilhafte Weiterbildungen der Erfindung werden in den abhängigen Patentansprüchen beschrieben .Advantageous developments of the invention are described in the dependent claims.
Eine vorteilhafte Weiterbildung der Erfindung sieht vor, dass der Indikator auf ein Substrat aufgebracht ist .An advantageous development of the invention provides that the indicator is applied to a substrate.
Durch das Substrat wird der Indikator in einer stabi- len Position gehalten . Dies ist insbesondere für sehr dünne Indikatorschichten vorteilhaft . Neben der Auftragung von Indikatoren in fester Phase eignet sich ein Substrat insbesondere für die Auftragung von Indikatoren in flüssiger und gasförmiger Phase . Des Weiteren erlaubt die Verwendung eines Substrats (bei entsprechender Gestaltung der Messvorrichtung) die gesonderte Präparation des Indikators : So könnte man beispielsweise das Substrat der Messvorrichtung entnehmen, in einer ersten Einrichtung reinigen, in ei- ner zweiten Einrichtung mit einer neuen Indikatorschicht ausstatten, und dann schließlich wieder in die Messvorrichtung integrieren . Neben der Auftragung des Indikators auf der Substratoberfläche kann das Substrat des Weiteren auch so gestaltet werden, dass es den Indikator abdeckt oder einschließt . Ebenfalls möglich ist, dass das Substrat mit dem Indikator getränkt, eingefärbt oder durchmischt ist, sowie auch eine Lösung des Indikators im Substrat möglich ist . Es ist allerdings zu beachten, dass die Eigenschaften des Substrats an die Strahlungsquelle angepasst wer- den .The indicator holds the indicator in a stable position through the substrate. This is particularly advantageous for very thin indicator layers. In addition to the application of indicators in solid phase, a substrate is particularly suitable for the application of indicators in the liquid and gaseous phase. Furthermore, the use of a substrate (with appropriate design of the measuring device) allows the separate preparation of the indicator: For example, one could remove the substrate of the measuring device, clean it in a first device, equip it with a new indicator layer in a second device, and then finally back in integrate the measuring device. In addition to the application of the indicator on the substrate surface, the substrate may also be designed to cover or enclose the indicator. It is also possible that the substrate is impregnated with the indicator, dyed or mixed, as well as a solution of the indicator in the substrate is possible. However, it should be noted that the properties of the substrate are adapted to the radiation source.
Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass das Substrat Glas oder eine Folie ist .A further advantageous development of the invention provides that the substrate is glass or a film.
Diesbezüglich soll insbesondere die Anwendung betont werden, einen Klebestreifen, der das Substrat darstellt, mit einem Indikator zu tränken oder einzufär- ben. Ein solch präparierter Klebestreifen stellt für sich selbst genommen eine erfindungsgemäße Messvorrichtung zum Messen photokatalytischer Aktivität dar . Aufgrund der Einfachheit solch eines Klebestreifens besteht ein hohes Anwendungspotential . Möchte man beispielsweise die photokatalytische Aktivität von mit einer photokatalytischen Schicht ausgestatteten Fenstern, Kacheln usw . messen, klebt man den präparierten Klebestreifen eine bestimmte Zeit auf die zu untersuchende photokatalytische Schicht auf, und wertet danach den Klebestreifen bequem in einer externen Einrichtung aus .In this regard, in particular, the application should be emphasized, with an indicator to soak or coloring an adhesive strip, which represents the substrate. Such a prepared adhesive strip, taken by itself, constitutes a measuring device according to the invention for measuring photocatalytic activity. Due to the simplicity of such an adhesive strip, there is a high application potential. For example, if one wants the photocatalytic activity of windows, tiles, etc, provided with a photocatalytic layer. measure, sticks the prepared adhesive strip for a certain time on the photocatalytic layer to be examined, and then evaluates the tape easily in an external device.
Auch zu erwähnen ist die Alternative, den Klebestreifen auf den Messkopf aufzukleben . Der Messkopf könnte für diesen Zweck beispielsweise mit einem Glasfenster ausgestattet sein . Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass die Messsonde einen Abstandshalter aufweist .Also worth mentioning is the alternative to stick the tape on the measuring head. The measuring head could, for example, be equipped with a glass window for this purpose. A further advantageous development of the invention provides that the measuring probe has a spacer.
Der Abstandshalter hat die Aufgabe, den Indikator und die Photokatalysator in einem definierten Abstand zu halten . Insbesondere wird dadurch die Reproduzierbarkeit und die Genauigkeit der Messungen unterstützt . Des Weiteren kann der Abstandshalter vorteilhafter- weise als Dichtungsring ausgebildet sein . Durch eine Abdichtung des Raums zwischen Indikator und Photokatalysator wird ein Entweichen der durch die Photokatalyse an der Oberfläche des Photokatalysators erzeugten und für die Übertragung des photokatalyti- sehen Effekts auf den Indikator notwendigen Radikale unterdrückt .The spacer has the task of keeping the indicator and the photocatalyst at a defined distance. In particular, this supports the reproducibility and the accuracy of the measurements. Furthermore, the spacer can advantageously be designed as a sealing ring. By sealing the space between the indicator and the photocatalyst, an escape of the radicals produced by the photocatalysis on the surface of the photocatalyst and necessary for the transmission of the photocatalytic effect to the indicator is suppressed.
Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass der Indikator ein organischer Farb- stoff, wie beispielsweise Methylenblau, ist , oder aus langkettigen aliphatischen Molekülen, wie beispielsweise Oleinsäure oder Stearinsäure, oder aus gut fluoreszierenden und hochstabilen Perylenderivaten besteht .A further advantageous development of the invention provides that the indicator is an organic dye, such as, for example, methylene blue, or consists of long-chain aliphatic molecules, such as, for example, oleic acid or stearic acid, or of highly fluorescent and highly stable perylene derivatives.
Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass die Strahlungsquelle in der Messsonde integriert ist .A further advantageous development of the invention provides that the radiation source is integrated in the measuring probe.
Ist die Strahlungsquelle in der Messvorrichtung integriert, so muss keine externe Strahlungsquelle zur Verfügung gestellt werden . Im Sinne einer handlichen Messvorrichtung eignet sich insbesondere der Einsatz von LEDs oder auch die Verwendung von Lichtleiterka- beln . Es bestehen viele Möglichkeiten, die Strahlungsquelle zur Bestrahlung der photokatalytischen Schicht zu positionieren. So kann beispielsweise die Strahlungsquelle hinter dem Indikator und, falls verwendet, das Substrat platziert werden, wodurch die photokatalyti- sche Schicht durch den Indikator und, falls verwendet, durch das Substrat hindurch bestrahlt wird. Diese Art von Einsatz der Strahlungsquelle macht allerdings den Einsatz eines Indikators und eines Sub- strats notwendig, die von der Strahlungsquelle in höchstens geringem Maße beeinflusst werden.If the radiation source is integrated in the measuring device, then no external radiation source must be made available. In the sense of a handy measuring device, the use of LEDs or the use of fiber optic cables is particularly suitable. There are many possibilities to position the radiation source for irradiation of the photocatalytic layer. Thus, for example, the radiation source can be placed behind the indicator and, if used, the substrate, whereby the photocatalytic layer is irradiated by the indicator and, if used, by the substrate. However, this type of use of the radiation source necessitates the use of an indicator and a substrate, which are influenced to a very small extent by the radiation source.
Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass die Strahlungsquelle Licht im UVA- Bereich erzeugt .A further advantageous development of the invention provides that the radiation source generates light in the UVA range.
Der geeignete Spektralbereich der durch die Strahlungsquelle erzeugten Strahlen hängt von den physikalischen Eigenschaften der photokatalytischen Schicht ab . Licht im UVA-Bereich eignet sich insbesondere für den Photokatalysator Titandioxid oder für Photokatalysatoren mit einer ähnlichen Bandlücke, wie beispielsweise für mit Stickstoff, Wolfram oder Niob- Eisen dotiertes Titandioxid, ebenso auch für die Pho- tokatalysatoren Zinkoxid und Zinnoxid.The appropriate spectral range of the beams generated by the radiation source depends on the physical properties of the photocatalytic layer. Light in the UVA range is particularly suitable for the photocatalyst titanium dioxide or for photocatalysts with a similar band gap, such as titanium dioxide doped with nitrogen, tungsten or niobium iron, as well as for the photocatalysts zinc oxide and tin oxide.
Verwendet man Photokatalysatoren mit anderen Eigenschaften, so muss die Strahlungsquelle entsprechend angepasst werden . Dementsprechend kann es vorteilhaft sein, Strahlungsquellen zu verwenden, die im UVB- Bereich arbeiten, oder auch im sichtbaren Bereich . Damit verbunden ist auch gegebenenfalls die Anpassung verwendeter optischer Komponenten .If photocatalysts with other properties are used, the radiation source must be adapted accordingly. Accordingly, it may be advantageous to use radiation sources that operate in the UVB range, or even in the visible range. Associated with this, if necessary, is the adaptation of used optical components.
Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass ein Detektor zum Messen des Abbaus des Indikators mittels Absorptionsmessungen/-Spek- troskopie, insbesondere Infrarotabsorptionsmessungen/-Spektroskopie, UV-VIS-Messungen/-Spektroskopie oder Fluoreszenzmessungen/-Spektroskopie in der Mess- sonde integriert ist .A further advantageous development of the invention provides that a detector for measuring the degradation of the indicator is integrated in the measuring probe by means of absorption measurements / spectroscopy, in particular infrared absorption measurements / spectroscopy, UV-VIS measurements / spectroscopy or fluorescence measurements / spectroscopy.
Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass eine Detektionsstrahlungsquelle zwecks Bestrahlung des Indikators zum Messen des Ab- baus des Indikators mittels Absorptionsmessungen/- Spektroskopie, insbesondere Infrarotabsorptionsmes- sungen/-Spektroskopie, UV-VIS-Messungen/-Spektroskopie oder Fluoreszenzmessungen/-Spektroskopie in der Messsonde integriert ist .A further advantageous development of the invention provides that a detection radiation source for irradiating the indicator for measuring the degradation of the indicator by means of absorption measurements / spectroscopy, in particular infrared absorption measurements / spectroscopy, UV-VIS measurements / spectroscopy or fluorescence measurements / Spectroscopy is integrated in the probe.
Durch die Detektionsstrahlungsquelle wird der Indikator bestrahlt . Der Detektor registriert die Antwort des bestrahlten Indikators . Ändert der Indikator aufgrund seiner Wechselwirkung mit dem aktiven Photoka- talysator seine physikalischen Eigenschaften, so registriert dieses der Detektor in einer sich ändernden Antwortfunktion des Indikators . Insbesondere Fluoreszenzmessungen erlauben die Detektion geringster Änderungen der Eigenschaften des Indikators .The indicator is irradiated by the detection radiation source. The detector records the response of the irradiated indicator. If the indicator changes its physical properties due to its interaction with the active photocatalyst, the detector registers this in a changing response function of the indicator. In particular, fluorescence measurements allow the detection of the least changes in the properties of the indicator.
Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass eine Vorrichtung zum Messung der Hyd- rophilie in der Messsonde integriert ist .A further advantageous development of the invention provides that a device for measuring the hydrophilicity is integrated in the measuring probe.
Ein Tropfen einer stark polaren Flüssigkeit, beispielsweise ein Wassertropfen, ändert auf einer pho- tokatalytisch aktiven Schicht seine Eigenschaften . So wird der am Anfang hohe Kontaktwinkel aufgrund des Einflusses der photokatalytischen Aktivität in kurzer Zeit, beispielsweise bei Wasser auf Titandioxid im solaren UVA-Licht in wenigen Minuten, stark redu- ziert . Kontaktwinkelmessungen, aber auch die Bestimmung der Tropfengröße, insbesondere des Tropfenradius erlauben eine Bewertung der Hydrophilie und damit auch eine Bewertung der photokatalytischen Aktivität der photokatalytischen Schicht . Hier soll insbesondere die Bestimmung des Tropfenradius betont werden, die sich mit einfachen Mitteln in der erfindungsgemäßen Messvorrichtung integrieren lässt .A drop of a strongly polar liquid, for example a drop of water, changes its properties on a photocatalytically active layer. Thus, the contact angle which is high at the beginning is greatly reduced in a few minutes owing to the influence of the photocatalytic activity in a short time, for example in the case of water on titanium dioxide in solar UVA light in a few minutes. graces. Contact angle measurements, but also the determination of the droplet size, in particular the droplet radius allow an evaluation of the hydrophilicity and thus also an evaluation of the photocatalytic activity of the photocatalytic layer. Here, in particular, the determination of the drop radius should be emphasized, which can be integrated with simple means in the measuring device according to the invention.
Eine weitere vorteilhafte Weiterbildung der Erfindung sieht vor, dass eine Messelektronik und/oder eine Stromversorgung der Strahlungsquellen in der Messsonde integriert ist .A further advantageous development of the invention provides that a measuring electronics and / or a power supply of the radiation sources is integrated in the measuring probe.
Die zuletzt genannten vorteilhaften Weiterbildungen haben das Ziel einer Messvorrichtung, die möglichst unabhängig von weiteren Einrichtungen ist . Dies spielt insbesondere für die Verwendung solch einer Messvorrichtung beispielsweise im Außeneinsatz eine Rolle . Des Weiteren ließen sich auch Anzeigelemente in der Messsonde integrieren, die sich ein sofortiges Ablesen der photokatalytischen Aktivität erlauben . Des Weiteren kann die Messvorrichtung auch mit geeigneten Schnittstellen zur Verbindung der Messvorrich- tung mit einem PC ausgestattet sein .The last-mentioned advantageous developments have the goal of a measuring device which is as independent as possible of other devices. This plays a role in particular for the use of such a measuring device, for example in outdoor use. Furthermore, it was also possible to integrate display elements in the measuring probe, which allow immediate reading of the photocatalytic activity. Furthermore, the measuring device can also be equipped with suitable interfaces for connecting the measuring device to a PC.
Des Weiteren offenbart die Erfindung ein Verfahren zur Messung der photokatalytischen Aktivität einer mit einer Strahlungsquelle bestrahlten photokatalyti- sehen Schicht, enthaltend den Schritt, dass ein auf die photokatalytische Aktivität reagierender Indikator zur Messung der photokatalytischen Aktivität in einem geringem Abstand zur photokatalytischen Schicht positioniert wird.The invention further discloses a method for measuring the photocatalytic activity of a photocatalytic layer irradiated with a radiation source, comprising the step of positioning an indicator, which reacts to the photocatalytic activity, for measuring the photocatalytic activity at a small distance from the photocatalytic layer.
In bekannten Verfahren wird der Indikator direkt und flächig auf die zu untersuchende photokatalytische Schicht aufgetragen . Damit verbunden sind Probleme, die bei der Präparation des Indikators entstehen können, die bei der Messung des Indikators entstehen können und die bei einem Entfernen des Indikators von der photokatalytischen Schicht entstehen können . Diese Probleme werden durch den erfindungsgemäßen Schritt , dass ein auf die photokatalytische Aktivität reagierender Indikator zur Messung der photokatalyti- sehen Aktivität in einem geringen Abstand zur photokatalytischen Schicht positioniert wird, vermieden . Eine großflächige Verbindung von Indikator und zu untersuchender photokatalytischen Schicht muss erfindungsgemäß für eine Bewertung der photokatalytischen Aktivität der photokatalytischen Schicht nicht gegeben sein : Befindet sich der Indikator in einem geringen Abstand zur photokatalytischen Schicht, so ist es ebenfalls möglich, zuverlässig die photokatalytische Aktivität der photokatalytischen Schicht zu messen . Hierbei sollen aber punktuelle Berührungen von Indikator und photokatalytischer Schicht nicht ausgeschlossen sein . Das erfindungsgemäße Verfahren erlaubt, wie schon in der Beschreibung der Vorrichtungsansprüche der vorliegenden Erfindung ausge- drückt, das zerstörungsfreie Messen der photokatalytischen Aktivität an beliebigen Orten .In known methods, the indicator becomes direct and applied flat on the photocatalytic layer to be examined. Associated with this are problems which may arise during the preparation of the indicator, which may arise during the measurement of the indicator and which may arise when the indicator is removed from the photocatalytic layer. These problems are avoided by the step according to the invention that an indicator which reacts to the photocatalytic activity for measuring the photocatalytic activity is positioned at a small distance from the photocatalytic layer. According to the invention, a large-area connection of indicator and photocatalytic layer to be examined does not have to be present for an evaluation of the photocatalytic activity of the photocatalytic layer: If the indicator is located at a small distance from the photocatalytic layer, it is likewise possible to reliably determine the photocatalytic activity of the photocatalytic layer to eat . In this case, however, punctual touches of indicator and photocatalytic layer should not be excluded. The method according to the invention, as already expressed in the description of the device claims of the present invention, permits the non-destructive measurement of the photocatalytic activity at arbitrary locations.
Unter "geringem Abstand" soll erfindungsgemäß verstanden werden, dass sich Indikator und photokataly- tische Schicht nicht berühren, wobei der maximale Abstand durch eine notwendige Mindestreaktion des Indikators gegeben ist (ist der Abstand indikatorphotoka- talytische Schicht zu groß , kann der Einfluss der aktiven Schicht auf den Indikator für eine sinnvolle Detektion zu gering sein) . Möglich sind beispielsweise Abstände von mehreren Millimetern, wobei dies al- lerdings auch abhängig von der Art des Aufbaus ist .According to the invention, "short distance" is to be understood as meaning that the indicator and the photocatalytic layer do not touch, the maximum distance being given by a necessary minimum reaction of the indicator (if the distance between the indicator photocatalytic layer is too great, the influence of the active layer to be too low on the indicator for meaningful detection). For example, distances of several millimeters are possible. However, it is also dependent on the type of construction.
Eine vorteilhafte Weiterbildung des Verfahrens sieht vor, dass die Strahlungsquelle die photokatalytische Schicht durch den Indikator hindurch bestrahlt und/oder die photokatalytische Schicht aus Richtung der dem Indikator abgewandten Seite bestrahlt und/oder die photokatalytische Schicht durch den sich zwischen dem Indikator und der photokatalytischen Schicht befindenden Spalt bestrahlt .An advantageous development of the method provides that the radiation source irradiates the photocatalytic layer through the indicator and / or irradiates the photocatalytic layer from the side facing away from the indicator and / or the photocatalytic layer through which it is located between the indicator and the photocatalytic layer Slit irradiated.
Es somit bei dem erfindungsgemäßen Verfahren ein flexibler Einsatz der Strahlungsquelle vorgesehen . So kann beispielsweise bei einer mit einer photokataly- tischen Schicht ausgestatteten Fensterscheibe die rückseitige Bestrahlung der photokatalytischen Schicht durch die Fensterscheibe hindurch vorteilhaft sein . Möchte man die photokatalytische Aktivität einer photokatalytischen Schicht auf Kacheln oder Flie- sen untersuchen, so bietet sich eine Bestrahlung der photokatalytischen Schicht durch den Indikator hindurch an . Sind beide genannten Fälle nicht möglich, so besteht immer noch die Möglichkeit, die photokatalytische Schicht durch eine Bestrahlung durch den sich zwischen Indikator und photokatalytischenIt thus provided in the inventive method, a flexible use of the radiation source. For example, in the case of a window pane equipped with a photocatalytic layer, the back irradiation of the photocatalytic layer through the window pane may be advantageous. If it is desired to investigate the photocatalytic activity of a photocatalytic layer on tiles or sheets, it is advisable to irradiate the photocatalytic layer through the indicator. If both of these cases are not possible, there is still the possibility of exposing the photocatalytic layer to radiation between the indicator and the photocatalytic layer
Schicht befindenden Spalt hindurch zu aktivieren .Layer to activate through gap.
Eine weitere vorteilhafte Weiterbildung des Verfahrens sieht vor, dass die photokatalytische Schicht vor der Messung der photokatalytischen Aktivität durch die Strahlungsquelle bestrahlt wird und/oder dass die photokatalytische Schicht während der Messung der photokatalytischen Aktivität durch die Strahlungsquelle bestrahlt wird.A further advantageous development of the method provides that the photocatalytic layer is irradiated by the radiation source prior to the measurement of the photocatalytic activity and / or that the photocatalytic layer is irradiated by the radiation source during the measurement of the photocatalytic activity.
Dies ist insbesondere dann vorteilhaft , wenn gleich- zeitiges Bestrahlen und Messen nicht möglich ist . Solche Fälle können beispielsweise bei Messobj ekten mit speziellen Geometrien, z . B . mit Vertiefungen oder Einschnitten, auftreten .This is particularly advantageous if the same early irradiation and measuring is not possible. Such cases, for example, in Messobj ekten with special geometries, eg. B. with depressions or incisions occur.
Eine weitere vorteilhafte Weiterbildung des Verfahrens sieht vor, dass sich während der Messung der photokatalytischen Aktivität ein Abstandshalter zwischen Messvorrichtung und photokatalytischer Schicht befindet .A further advantageous development of the method provides that during the measurement of the photocatalytic activity there is a spacer between the measuring device and the photocatalytic layer.
Der Abstandshalter hat den Zweck, Indikator und ' pho- tokatalytische Schicht in einem definierten Abstand zu halten . Des Weiteren kann der Abstandshalter als Dichtungsring gestaltet sein . Dadurch wird einem Entweichen der durch die Photokatalyse erzeugten und für die Übertragung des photokatalytischen Effekts notwendigen Radikale aus dem Spalt zwischen Indikator und photokatalytischer Schicht entgegengewirkt . Dies erhöht die Reproduzierbarkeit und Genauigkeit der Messungen .The spacer has to keep the purpose indicator and 'photo- tokatalytische layer in a defined distance. Furthermore, the spacer may be designed as a sealing ring. This counteracts the escape of the radicals generated by the photocatalysis and necessary for the transfer of the photocatalytic effect from the gap between the indicator and the photocatalytic layer. This increases the reproducibility and accuracy of the measurements.
Der Abstandshalter kann sich an der Messvorrichtung befinden . Ebenso kann dieser Abstandshalter an der zu untersuchen photokatalytischen Schicht angebracht sein . Es kann sich bei dem Abstandshalter aber auch um ein einzelnes Obj ekt handeln, das in dem erfindungsgemäßen Verfahren sinngemäß eingesetzt wird.The spacer may be located on the measuring device. Likewise, this spacer may be attached to the photocatalytic layer to be examined. However, the spacer may also be a single object, which is used analogously in the method according to the invention.
Eine weitere vorteilhafte Weiterbildung des Verfahrens sieht vor, dass als Messvorrichtung eine Messvorrichtung nach den Ansprüchen 1 bis 11 verwendet wird.A further advantageous development of the method provides that a measuring device according to claims 1 to 11 is used as measuring device.
Die Erfindung wird nun anhand zweier Figuren erläutert . Dabei zeigt Figur 1 eine erfindungsgemäße Messvorrichtung zur Messung photokatalytischer Aktivität einer mit einer Strahlungsquelle bestrahlten pho- tokatalytischen Schicht, undThe invention will now be explained with reference to two figures. It shows FIG. 1 shows a measuring device according to the invention for measuring the photocatalytic activity of a photocatalytic layer irradiated with a radiation source, and
Figur 2 eine Messvorrichtung nach Stand der Technik.2 shows a measuring device according to the prior art.
Figur 1 zeigt eine Messvorrichtung zur Messung photokatalytischer Aktivität einer mit einer Strahlungsquelle bestrahlten photokatalytischen Schicht .FIG. 1 shows a measuring device for measuring the photocatalytic activity of a photocatalytic layer irradiated with a radiation source.
Die Messvorrichtung enthält eine Messsonde 1. Der Messkopf dieser Messsonde 1 wird gebildet durch einen Indikator 5, der sich auf einem Substrat 6 befindet . Der Indikator besteht aus Methylenblau, einem organischen Farbstoff . Das Substrat, auf dem sich der Indikator 5 befindet, ist eine UVA-lichtdurchlässige Glasplatte . Des Weiteren ist die Messvorrichtung 1 ausgestattet mit einer Strahlungsquelle 2. Die Strahlungsquelle 2 ist in diesem Falle eine LED, die im UVA-Bereich arbeitet . Sie ist innerhalb der Messvorrichtung 1 hinter dem Indikator 5 und dem Substrat 6 platziert . Damit ist möglich, die sich vor dem Messkopf, insbesondere vor dem Indikator 5 , befindende Fläche zu bestrahlen .The measuring device contains a measuring probe 1. The measuring head of this measuring probe 1 is formed by an indicator 5 which is located on a substrate 6. The indicator consists of methylene blue, an organic dye. The substrate on which the indicator 5 is located is a UVA translucent glass plate. Furthermore, the measuring device 1 is equipped with a radiation source 2. The radiation source 2 in this case is an LED which operates in the UVA range. It is placed inside the measuring device 1 behind the indicator 5 and the substrate 6. This makes it possible to irradiate the surface located in front of the measuring head, in particular in front of the indicator 5.
Des Weiteren sind integriert in der Messvorrichtung 1 eine Detektionsstrahlungsquelle 9 und ein Detektor 8. Die Detektionsstrahlungsquelle ist ebenfalls in diesem Ausführungsbeispiel als LED ausgebildet und arbeitet im Rotbereich des sichtbaren Spektrums . Sie ist demnach geeignet, den Indikator 5 zur Fluoreszenz anzuregen. Dementsprechend ist die Detektionsbestrah- lungsquelle 9 in Nähe des Indikators 5 positioniert , um diesen möglichst großflächig zu bestrahlen . Ändern sich die Fluoreszenzeigenschaften des Indikators 5 , so wird dieses über den Detektor 8 detektiert . Dieser Detektor 8 befindet sich dementsprechend ebenfalls in Nähe der Indikatorschicht 5.Furthermore, a detection radiation source 9 and a detector 8 are integrated in the measuring device 1. The detection radiation source is likewise embodied as an LED in this exemplary embodiment and operates in the red region of the visible spectrum. It is therefore suitable to stimulate the indicator 5 to fluorescence. Accordingly, the detection irradiation source 9 is positioned near the indicator 5, to irradiate this as large as possible. If the fluorescence properties of the indicator 5 change, this is detected via the detector 8. Accordingly, this detector 8 is likewise located in the vicinity of the indicator layer 5.
Alternativ ist es auch möglich, die Absorption des Indikators 5 zu messen . Dies kann entweder in Reflexion oder aber auch in Transmission erfolgen. Auch kann als Detektionsstrahlungsquelle anstatt einer LED im Rotbereich eine Detektionsstrahlungsquelle benutzt werden, die im VIS-Bereich oder im UV-VIS-Bereich arbeitet .Alternatively, it is also possible to measure the absorption of the indicator 5. This can be done either in reflection or in transmission. Also, as a detection radiation source instead of an LED in the red area, a detection radiation source can be used which operates in the VIS range or in the UV-VIS range.
Die Stromversorgung zur Betreibung der Strahlungsquellen und des Detektors sowie die für den Betrieb der Messvorrichtung notwendige Messelektronik ist in dem hinteren Bereich 10 der Messvorrichtung unterge- bracht, auf der anderen Seite des Messkopfes liegend . Nicht zeichnerisch dargestellt sind Anzeigeelemente, die ebenfalls im Bereich 10 integriert sind. Über ein Datenkabel 11 ist die Messvorrichtung 1 mit einem hier nicht dargestellten PC verbunden.The power supply for operating the radiation sources and the detector as well as the measuring electronics necessary for the operation of the measuring device are accommodated in the rear area 10 of the measuring device, lying on the other side of the measuring head. Not shown in the drawing are display elements which are also integrated in area 10. Via a data cable 11, the measuring device 1 is connected to a PC, not shown here.
Die Messvorrichtung 1 ist mit ihrem Messkopf auf eine photokatalytische Schicht 3 gerichtet . Die photokata- lytische Schicht 3 besteht aus dem Photokatalysator Titandioxid. Die photokatalytische Schicht 3 bildet die Oberfläche einer Fensterscheibe 4. Der Abstand zwischen photokatalytischer Schicht 3 und Indikator 5 wird durch einen Abstandshalter 7 vorgegeben . Dieser Abstandshalter 7 befindet sich direkt an der Messvorrichtung 1. Durch ihn werden der Indikator und die photokatalytische Schicht parallel in diesem Ausführungsbeispiel einem Abstand von 0 , 5 mm gehalten . Mög- lieh sind aber auch größere Abstände von bis zu mehreren Millimetern . Des Weiteren ist der Abstandshalter als Dichtungsring konzipiert, wodurch der Luftaustausch zwischen dem Spalt zwischen Indikator 5 und photokatalytischer Schicht 3 mit dem Außenbereich unterbunden ist .The measuring device 1 is directed with its measuring head onto a photocatalytic layer 3. The photocatalytic layer 3 consists of the photocatalyst titanium dioxide. The photocatalytic layer 3 forms the surface of a window pane 4. The distance between the photocatalytic layer 3 and the indicator 5 is predetermined by a spacer 7. This spacer 7 is located directly on the measuring device 1. Through it, the indicator and the photocatalytic layer are held in parallel in this embodiment, a distance of 0.5 mm. possible But leh are also larger distances of up to several millimeters. Furthermore, the spacer is designed as a sealing ring, whereby the air exchange between the gap between indicator 5 and photocatalytic layer 3 is prevented with the outside.
Die photokatalytische Aktivität der photokatalyti- schen Schicht 3 lässt sich nach dem erfindungsgemäßen Verfahren messen . Dies soll anhand eines Ausführungsbeispiels gezeigt werden .The photocatalytic activity of the photocatalytic layer 3 can be measured by the method according to the invention. This will be shown with reference to an embodiment.
Um die photokatalytische Aktivität der photokatalyti- schen Schicht 3 nach dem erfindungsgemäßen Verfahren zu messen, führt man die Messsonde 1 mit dem präparierten Indikator 5 an die zu untersuchende photokatalytische Schicht 3 heran, so dass sich Indikator 5 und photokatalytische Schicht in einem geringen Abstand befinden . Diese Situation zeigt die Figur 1.In order to measure the photocatalytic activity of the photocatalytic layer 3 by the method according to the invention, the measuring probe 1 with the prepared indicator 5 is brought to the photocatalytic layer 3 to be examined so that the indicator 5 and the photocatalytic layer are at a small distance. This situation is shown in FIG. 1.
Um die photokatalytische Schicht 3 zu aktivieren, muss diese mit einer geeigneten Strahlungsquelle bestrahlt werden . Die Bestrahlung kann durch den Indikator hindurch und/oder aus Richtung der dem Indika- tor abgewandten Seite und/oder durch den sich zwischen dem Indikator und der photokatalytischen Schicht befindenden Spalt erfolgen . Figur 1 zeigt die Situation, in der die Strahlungsquelle 2 hinter dem Indikator 5 angeordnet ist : Die photokatalytische Schicht 3 wird hier durch den Indikator 5 hindurch bestrahlt .To activate the photocatalytic layer 3, it must be irradiated with a suitable radiation source. The irradiation can take place through the indicator and / or from the direction of the side facing away from the indicator and / or through the gap located between the indicator and the photocatalytic layer. FIG. 1 shows the situation in which the radiation source 2 is arranged behind the indicator 5: the photocatalytic layer 3 is irradiated through the indicator 5.
Wie Figur 1 zeigt, wird durch einen Abstandshalter 7 der Indikator 5 und die photokatalytische Schicht in einem definierten Abstand gehalten . In diesem Falle befindet sich der Abstandshalter an der Messsonde . Um einen Effekt zu beobachten, wird die photokataly- tische Schicht 3 durch Bestrahlung mittels der Strahlungsquelle 2 aktiviert . Die photokatalytische Schicht 3 kann nun vor der Messung der photokatalyti- schen Aktivität aktiviert werden, oder aber die photokatalytische Schicht 3 wird gleichzeitig mit der Messung der photokatalytischen Aktivität aktiviert, wie es für dieses Ausführungsbeispiel angenommen sein soll .As FIG. 1 shows, the indicator 5 and the photocatalytic layer are kept at a defined distance by means of a spacer 7. In this case, the spacer is located on the probe. In order to observe an effect, the photocatalytic layer 3 is activated by irradiation by means of the radiation source 2. The photocatalytic layer 3 can now be activated before the measurement of the photocatalytic activity, or else the photocatalytic layer 3 is activated simultaneously with the measurement of the photocatalytic activity, as should be assumed for this exemplary embodiment.
Durch die photokatalytische Aktivität der photokatalytischen Schicht 3 ändern sich die Absorptions- und Fluoreszenzeigenschaften des Indikators 5. Über Ab- sorptions- oder Fluoreszenzmessungen/-spektroskopie mittels der Detektionsstrahlungsquelle 9 und des Detektors 8 werden diese Änderungen des Indikators 5 registriert .The photocatalytic activity of the photocatalytic layer 3 changes the absorption and fluorescence properties of the indicator 5. These changes in the indicator 5 are registered via absorption or fluorescence measurements / spectroscopy by means of the detection radiation source 9 and the detector 8.
Über die Änderung der Absorptions- oder Fluoreszenzeigenschaften des Indikators 5 erhält man Aufschluss über die photokatalytische Aktivität der photokatalytischen Schicht 3 , die sich auf dem hier in der Figur 1 nicht näher dargestellten Anzeigeelement oder auf dem PC ablesen lassen.The change in the absorption or fluorescence properties of the indicator 5 provides information about the photocatalytic activity of the photocatalytic layer 3, which can be read off on the display element (not shown here in detail in FIG. 1) or on the PC.
Die in Figur 1 gezeigte Messvorrichtung beschränkt sich in ihrer Darstellung auf eine Messung des photokatalytischen Effekts mittels Spektroskopie . Dies soll aber nicht ausschließen, dass eine Vorrichtung zur Messung der Hydrophilie des Photokatalysators in der Messsonde 1 ergänzt werden kann, oder sogar die für die Spektroskopie notwendigen Komponenten vollständig ersetzt . Solch eine Vorrichtung könnte bei- spielsweise ein Videosystem enthalten . Bringt man nun definiert einen Wassertropfen auf die Oberfläche des Photokatalysators 3 auf, so könnte mit dem Videosystem das zeitliche Verhalten des Wassertropfens beobachtet werden . Diesbezüglich bietet sich beispielsweise die Beobachtung des Tropfenradius oder des Kon- taktwinkels an. Das zeitliche Verhalten des Wassertropfens wiederum gibt Aufschluss über die Aktivität des Photokatalysators 3.The measuring device shown in Figure 1 is limited in its presentation to a measurement of the photocatalytic effect by means of spectroscopy. However, this should not exclude that a device for measuring the hydrophilicity of the photocatalyst in the probe 1 can be supplemented, or even completely replaced the necessary components for spectroscopy. Such a device could include, for example, a video system. Now bring a defined drop of water on the surface of the Photocatalyst 3, it could be observed with the video system, the temporal behavior of the water droplet. In this regard, for example, it is advisable to observe the drop radius or the contact angle. The temporal behavior of the water droplet in turn provides information about the activity of the photocatalyst 3.
Figur 2 zeigt eine Messvorrichtung nach Stand der Technik.FIG. 2 shows a measuring device according to the prior art.
Dargestellt ist eine Fensterscheibe 4 , die mit einem Photokatalysator 3 beschichtet ist . Auf die Oberfläche des Photokatalysators ist Indikator 5 im unmit- telbaren und flächigen Kontakt zum Photokatalysator aufgetragen . Über dieser Anordnung, dem Indikator direkt gegenüberliegend, ist eine Strahlungsquelle 2 positioniert . Mittels der Strahlungsquelle wird der Photokatalysator 3 aktiviert . Durch die photokataly- tische Aktivität des Photokatalysators 3 wird der Indikator 5 abgebaut . Dieser Abbau ist beispielsweise mittels Absorptionsspektroskopie nachweisbar . Shown is a window 4, which is coated with a photocatalyst 3. Indicator 5 is applied to the surface of the photocatalyst in direct and planar contact with the photocatalyst. About this arrangement, the indicator directly opposite, a radiation source 2 is positioned. By means of the radiation source, the photocatalyst 3 is activated. Due to the photocatalytic activity of the photocatalyst 3, the indicator 5 is degraded. This degradation is detectable for example by means of absorption spectroscopy.

Claims

Patentansprüche claims
1. Messvorrichtung zur Messung photokatalytischer Aktivität einer mit einer Strahlungsquelle ( 2 ) bestrahlten photokatalytischen Schicht ( 3 ) , wobei die Messvorrichtung eine Messsonde (1) mit einem Messkopf enthält, und der Messkopf mit einem auf die photokatalytische Aktivität der photokatalytischen Schicht reagierenden Indikator ( 5 ) ausgestattet ist, der zur Messung der photokatalytischen Aktivität mit Abstand zur photoka- talytischen Schicht positionierbar ist .1. Measuring device for measuring the photocatalytic activity of a photocatalytic layer (3) irradiated with a radiation source (2), the measuring device comprising a measuring probe (1) with a measuring head, and the measuring head having an indicator (5) which reacts to the photocatalytic activity of the photocatalytic layer ), which can be positioned to measure the photocatalytic activity at a distance from the photocatalytic layer.
2. Vorrichtung nach Anspruch 1 , dadurch gekennzeichnet, dass der Indikator ( 5) auf ein Substrat ( 6) aufgebracht ist .2. Apparatus according to claim 1, characterized in that the indicator (5) is applied to a substrate (6).
3. Vorrichtung nach Anspruch 2 , dadurch gekenn- zeichnet, dass das Substrat ( β) Glas oder eine3. Apparatus according to claim 2, characterized in that the substrate (β) glass or a
Folie ist .Foil is.
4. Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Messsonde ( 1 ) einen Abstandshalter ( 7 ) aufweist .4. Device according to one of the preceding claims, characterized in that the measuring probe (1) has a spacer (7).
5. Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Indikator ( 5 ) ein organischer Farbstoff, wie beispielsweise Methylenblau, ist, oder aus langket- tigen aliphatischen Molekülen, wie beispielswei- se Oleinsäure oder Stearinsäure, oder aus gut fluoreszierenden und hochstabilen Perylenderiva- ten besteht . 5. Device according to one of the preceding claims, characterized in that the indicator (5) is an organic dye, such as methylene blue, or from langket- term aliphatic molecules, such as oleic acid or stearic acid, or from highly fluorescent and highly stable Perylene derivatives exists.
6. Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Strahlungsquelle (2 ) in der Messsonde (1) integriert ist .6. Device according to one of the preceding claims, characterized in that the radiation source (2) in the measuring probe (1) is integrated.
7. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass die Strahlungsquelle (2 ) Licht im UVA-Bereich erzeugt .7. Apparatus according to claim 6, characterized in that the radiation source (2) generates light in the UVA range.
8. Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass ein Detek- tor' ( 8 ) zur Messung des Abbaus des Indikators8. Device according to one of the preceding claims, characterized in that a detec- tor ' (8) for measuring the degradation of the indicator
(5 ) mittels Absorptionsmessungen/-spektroskopie, insbesondere Infrarotabsorptionsmessungen/- spektroskopie, UV-VIS-Messungen/-Spektroskopie oder Fluoreszensmessungen/-spektroskopie in der Messsonde integriert ist .(5) is integrated in the measuring probe by means of absorption measurements / spectroscopy, in particular infrared absorption measurements / spectroscopy, UV-VIS measurements / spectroscopy or fluorescence measurements / spectroscopy.
9. Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass eine De- tektionsstrahlungsquelle ( 9) zwecks Bestrahlung des Indikators (5) zur Messung des Abbaus des Indikators mittels Absorptionsmessungen/- spektroskopie, insbesondere Infrarotabsorptions- messungen/-Spektroskopie, UV-VIS-Messungen/- Spektroskopie oder Fluoreszensmessungen/- spektroskopie in der Messsonde integriert ist .9. Device according to one of the preceding claims, characterized in that a detection radiation source (9) for irradiating the indicator (5) for measuring the degradation of the indicator by means of absorption measurements / - spectroscopy, in particular infrared absorption measurements / spectroscopy, UV-VIS Measurements / spectroscopy or fluorescence measurements / spectroscopy is integrated in the probe.
10. Vorrichtung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet , dass eine Vorrichtung zur Messung der Hydrophilie in der Messsonde integriert ist .10. Device according to one of the preceding claims, characterized in that a device for measuring the hydrophilicity is integrated in the measuring probe.
11. Vorrichtung nach einem der Ansprüche 6-10 , da- durch gekennzeichnet, dass eine Messelektronik11. Device according to one of claims 6-10, character- ized in that a measuring electronics
( 10 ) und/oder eine Stromversorgung ( 10 ) der Strahlungsquellen in der Messsonde integriert ist . (10) and / or a power supply (10) of the radiation sources is integrated in the measuring probe.
12. Verfahren zur Messung der photokatalytischen Aktivität einer mit einer Strahlungsquelle (2) bestrahlten photokatalytischen Schicht ( 3 ) enthaltend den Schritt, dass ein auf die photokataly- tische Aktivität reagierender Indikator ( 5) zur12. A method for measuring the photocatalytic activity of a radiation source (2) irradiated photocatalytic layer (3) comprising the step that an on the photocatalytic activity-reacting indicator (5) for
Messung der photokatalytischen Aktivität in einem geringen Abstand zur photokatalytischen Schicht (3) positioniert wird.Measurement of the photocatalytic activity is positioned at a small distance to the photocatalytic layer (3).
13. Verfahren nach Anspruch 12 , dadurch gekennzeich- net , dass die Strahlungsquelle (2 ) die photoka- talytische Schicht ( 3 ) durch den Indikator ( 5 ) hindurch bestrahlt und/oder die photokatalyti- sche Schicht ( 3 ) aus Richtung der dem Indikator abgewandten Seite bestrahlt und/oder die photo- katalytische Schicht ( 3) durch den sich zwischen dem Indikator (5) und der photokatalytischen Schicht befindenden Spalt bestrahlt .13. The method according to claim 12, characterized in that the radiation source (2) irradiates the photocatalytic layer (3) through the indicator (5) and / or the photocatalytic layer (3) from the direction of the indicator irradiated on the opposite side and / or the photocatalytic layer (3) through the located between the indicator (5) and the photocatalytic layer gap irradiated.
14. Verfahren nach Anspruch 12 oder 13 , dadurch gekennzeichnet, dass die photokatalytische Schicht ( 3 ) vor der Messung der photokatalytischen Aktivität durch die Strahlungsquelle ( 2) bestrahlt wird und/oder dass die photokatalytische Schicht während der Messung der photokatalytischen Aktivität durch die Strahlungsquelle bestrahlt wird .14. The method according to claim 12 or 13, characterized in that the photocatalytic layer (3) before the measurement of the photocatalytic activity by the radiation source (2) is irradiated and / or that the photocatalytic layer irradiated during the measurement of the photocatalytic activity by the radiation source becomes .
15. Verfahren nach einer der Ansprüche 12 bis 14 , dadurch gekennzeichnet, dass sich während der Messung der photokatalytischen Aktivität ein Abstandshalter (7 ) zwischen Messvorrichtung und photokatalytischer Schicht (3) befindet .15. The method according to any one of claims 12 to 14, characterized in that there is a spacer (7) between the measuring device and photocatalytic layer (3) during the measurement of the photocatalytic activity.
16. Verfahren zur Messung der photokatalytischen Aktivität nach einer der Ansprüche 12 bis 15 , dadurch gekennzeichnet, dass als Messvorrichtung eine Messvorrichtung nach den Ansprüchen 1-11 verwendet wird. 16. A method for measuring the photocatalytic activity according to any one of claims 12 to 15, characterized in that as a measuring device a measuring device according to claims 1-11 is used.
PCT/EP2006/000679 2005-01-24 2006-01-23 Measuring device and measuring method for measuring photocatalytic activity of a photocatalytic layer WO2006077169A1 (en)

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