WO2011092208A1

WO2011092208A1 - Reaction chamber for studying a solid-gas interaction

Info

Publication number: WO2011092208A1
Application number: PCT/EP2011/051075
Authority: WO
Inventors: Birger Maria Jan Hauchecorne; Dieter Gaby Marc Terrens; Floris Jozef Geert Vanpachtenbeke; Silvia Katelijne Lenaerts; Tom Tytgat
Original assignee: University Of Antwerp
Priority date: 2010-01-27
Filing date: 2011-01-26
Publication date: 2011-08-04
Also published as: GB201001307D0

Abstract

The invention relates to a reaction chamber, said reaction chamber being adapted to accommodate a gas-porous separation entity (2) in such a way that said gas-porous separation entity (2) separates said chamber (1) into a first and a second unit (13, 14) so that said gas-porous separation entity (2) is the only pathway for gas between said first unit (13) and said second unit (14), said reaction chamber (1) comprising: - a first gas port (3) in said first unit (13), - a second gas port (4) in said second unit (14), and being further adapted to accommodate the transversal of said reaction chamber by an electromagnetic radiation wherein said adaptation to accommodate the transversal of said reaction chamber by said electromagnetic radiation comprises: - a first aperture (5) in said first unit (13) and a second aperture (6) in said second unit (14) for allowing said electromagnetic radiation (7) to traverse said reaction chamber (1) from said first aperture (5) to said second aperture (6), and - a first and a second gas-impermeable window (8, 9), substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to prevent gas from escaping via said first and second apertures (5, 6) respectively.

Description

Reaction chamber for studying a solid-gas interaction

Technical field of the invention

The present invention relates to a reaction chamber for studying the interaction of a gas with a solid material such as a photocatalytic gas-porous material. It further relates to a reactor comprising said reaction chamber and to a method for using said reactor.

Background of the invention

It is important for the understanding of gas-solid interactions such as, for instance, photocatalytic reactions between a gas and a photo-activated Ti0₂ substrate, to develop devices able to monitor the species which are formed on the solid surface itself rather than what can be found in the gas phase after the interaction/reaction has occurred.

Chemical detecting apparatuses are known which have for purpose of detecting the (harmful) chemicals present in the atmosphere.

US 2004/0108472 discloses a chemical detecting apparatus comprising: a substrate for a chemical in a gas-to-be-monitored to be adsorbed to; an adsorption rate improving means, actually a cooling means, for enhancing the adsorption of the chemical in the gas- to-be-monitored to the substrate; an infrared application means for applying an infrared light to the substrate with the chemical adsorbed to; an infrared analyzing means which analyzes the infrared light exiting the substrate after passed through the substrate to thereby identify a kind of the chemical adsorbed to the substrate and/or compute an adsorption amount of the chemical; and a chemical detecting means which identifies a kind of the chemical in the gas-to-be-monitored and/or compute an adsorption amount of the chemical, based on an analysis result given by the infrared analyzing means. The purpose of this device is to identify the kind of chemical adsorbed on the substrate and/or compute an adsorption amount of the chemical; and identifying the kind of chemical in the gas-to- be-monitored and/or computing a concentration of the chemical, based on the amount of the chemical adsorbed on the substrate.

Such a device presents various features that would make its use for the study of a gas- solid interaction difficult. In particular, the ratio between the amount of gas adsorbed on the substrate to the amount of non-adsorbed gas present in the optical path separating the emitter from the detector is very small rendering extrapolation unreliable. For this reason, adsorption-enhancing techniques are used in this prior art such as cooling of the substrate. This requires cooling means, which are both bulky and expensive.

Summary of the invention

It is an object of the present invention to provide an improved apparatus or methods for studying the interaction of a gas with a solid material.

It is an advantage of embodiments of the present invention that a high sensitivity toward chemical species adsorbed on the solid substrate can be achieved.

It is an advantage of embodiments of the present invention that no cooling means are required to enhance the detection of gases adsorbed on the solid surface.

It is a further advantage of embodiments of the present invention that the apparatus provided is simple and inexpensive.

The above objective is accomplished by a method and device according to the present invention.

In a first aspect, the present invention relates to a reaction chamber adapted to accommodate a gas-porous separation entity (or in other words a gas-porous separation wall) in such a way that said gas-porous separation entity separates said chamber into a first and a second unit so that said gas-porous separation entity is the only pathway for gas between said first unit and said second unit, said reaction chamber comprising:

- a first gas port (e.g. for use as a gas inlet) in said first unit,

- a second gas port (e.g. for use as a gas outlet) in said second unit,

and being further adapted to accommodate a transversal of said reaction chamber by an electromagnetic radiation wherein said adaptation to accommodate said transversal of said reaction chamber by said electromagnetic radiation comprises:

- a first aperture in said first unit and a second aperture in said second unit for

allowing said electromagnetic radiation to traverse said reaction chamber from said first aperture to said second aperture, and

- a first and a second gas-impermeable window, substantially transparent to at least part of the spectrum of said electromagnetic radiation, placed so as to prevent gas from escaping via said first and second apertures respectively (or in other words placed so as to provide the capability of preventing gas from escaping via said first and second apertures). The gas ports are connecting the inside of the reaction chamber with the outside of the reaction chamber and serve as gas inlet or outlet for the reaction chamber.

This is advantageous as the adaptation for accommodating a gas-porous separation entity in this way permits gas adsorbed on a much larger contact surface between the gas and the solid to be realized by forcing the gas to flow through the thickness of the gas- porous material. In this way, the ratio between the amount of gas adsorbed on and in the material to the amount of non-adsorbed gas present in the optical path separating the emitter from the detector is large and the signal observed is representative of the adsorbed chemical species.

In a second aspect, the present invention relates to a reactor comprising:

- a reaction chamber,

- an emitter of electromagnetic radiation, and

- a detector of said electromagnetic radiation for generating analytical data .

In a third aspect, the present invention relates to a method of studying the interaction of a gas with a gas-porous material comprising the steps in a reaction chamber (1) containing a gas-porous separation entity (2) in such a way that said gas-porous separation entity (2) separates said chamber (1) in a first and a second unit (13, 14) so that said gas- porous separation entity (2) is the only pathway for gas between said first unit (13) and said second unit (14), said reaction chamber (1) comprising:

- a first gas port (3) in said first unit (13), said first gas port being used as a gas inlet or as a gas outlet,

- a second gas port (4) in said second unit (14), said second gas port being used as a gas inlet, if said first gas port is used as a gas outlet, or as a gas outlet, if said first gas port is used as a gas inlet,

- a first aperture (5) in the first unit (13) and a second aperture (6) in the second unit

(14) for allowing an electromagnetic radiation (7) to traverse said reaction chamber (1) from said first aperture (5) to said second aperture (6), and

- a first and a second gas-impermeable window (8, 9), substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to prevent gas from escaping by said first and second apertures (5, 6) respectively, (i) introducing said gas into said reaction chamber (1) via said first gas port (3) or said second gas port (4), (ii) emitting said electromagnetic radiation (7) through and from said first or second aperture (5, 6) to said second or first aperture (6, 5) respectively, and

(iii) detecting said electromagnetic radiation (7) through said second or first aperture (6, 5) respectively.

In a fourth aspect, the invention may relate to a kit of parts for assembling a reaction chamber (2) according to claim 1, comprising:

- a first unit (13) comprising:

(i) an opening (S13),

(ii) said first gas port (3) in addition to said opening (S13),

(iii) said first aperture (5) for allowing an electromagnetic radiation (7) to traverse said first unit (13) from said first aperture (5) to said first opening (S13) or from said first opening (S13) to said first aperture (5),

(iv) said first gas impermeable window (8), substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to prevent gas from escaping via said first aperture (5),

- a second unit (14) comprising:

(i) a second opening (S14),

(ii) said second gas port (4) in addition to said opening S14,

(iii) said second aperture (6) for allowing an electromagnetic radiation (7) to traverse said second unit (14) from said aperture (6) to said opening (S14) or from said first opening (S14) to and through said first aperture (6),

(iv) said second gas impermeable window (9), substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to prevent gas from escaping via said second aperture (6),

wherein said first unit (13) and said second unit (14) are adapted to be attachable to each other by connecting said first opening (S13) with said second opening (S14) so as to form said reaction chamber (1).

All embodiments of the first aspect may also apply to this fourth aspect.

In a fifth aspect, the present invention may relate to a first or second unit for assembling a reaction chamber (1) according to any embodiment of the first aspect, said first or second unit comprising:

(i) an opening (SI 3 or S14), (ii) a gas port in addition to said opening (SI 3 or SI 4),

(iii) an aperture for allowing an electromagnetic radiation (7) to traverse said first or second unit from said aperture to said opening or from said opening to said aperture,

(iv) a gas impermeable window, substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to prevent gas from escaping via said aperture,

wherein said first or second unit comprises connection means for attaching to a second or first unit respectively having complementary connection means.

All embodiments of the first aspect may also apply to this fifth aspect.

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.

Although there has been constant improvement, change and evolution of devices in this field, the present concepts are believed to represent substantial new and novel improvements, including departures from prior practices, resulting in the provision of more efficient, stable and reliable devices of this nature.

The teachings of the present invention permit the design of improved methods and apparatus for studying the interaction between a gas and a solid. Embodiments of the present invention also permit gas detection. Further embodiments of the present invention also permit the study of the photocatalytic activity of a solid.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Brief description of the drawings

Fig. 1 is a schematic representation of an embodiment of the present invention.

Fig. 2 are schematic representations of perspective views of embodiments of the present invention (b, c, d) or is a schematic representation of a perspective view of a part of a reaction chamber (a). Fig. 3 is a schematic representation of a perspective view of an embodiment of the present invention.

Fig. 4 is a cross-sectional side view of an embodiment of the present invention.

Fig. 5 is an explode view of the embodiment of Fig. 4.

Fig. 6 is a schematic representation of a perspective view of an embodiment of the present invention.

Fig. 7 is a block diagram illustrating a highly simplified embodiment of the invention. Fig. 8 shows FT-IR spectra as absorption, A, as a function of wavenumber (l/λ) in an in- situ reactor according to the present invention with Aerolyst® 7710 disks (120 mg material): a) general view; (b) the wavenumber range between 3350 cm^"1 and 4000 cm^"1 Percentage indicates the amount of KBr.

In the different figures, the same reference signs refer to the same or analogous elements.

Description of illustrative embodiments

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein. It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

Furthermore, some of the embodiments are described herein as a method or combination of elements of a method that can be implemented by a processor of a computer system or by other means of carrying out the function. Thus, a processor with the necessary instructions for carrying out such a method or element of a method forms a means for carrying out the method or element of a method. Furthermore, an element described herein of an apparatus embodiment is an example of a means for carrying out the function performed by the element for the purpose of carrying out the invention.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

The following terms are provided solely to aid in the understanding of the invention.

Definitions

As used herein and unless specified otherwise, the term "gas-porous" means possessing pores making it permeable to at least one gas under the ambient conditions pertaining. The porous material should be chosen in such a way that it is permeable to the gas under investigation and to its carrier gas if present.

As used herein and unless provided otherwise, the term "at least partly transparent" means allowing the transmission of at least 20% of the part of the electromagnetic spectrum referred to.

As used herein and unless provided otherwise, the term "analytically relevant electromagnetic radiation" refers to an electromagnetic radiation that can be used to determine physico-chemical properties of a gas or of a porous material. For instance, analytically relevant electromagnetic radiation can extend from the far infra-red to the deep ultra-violet. Preferably, the electromagnetic radiation used is in the infra-red. Preferably the electromagnetic radiation used can extend from 780 nm to 500 μιη.

As used herein and unless provided otherwise, the term "substantially transparent" means allowing the transmission of at least 85% of the part of the electromagnetic spectrum referred to. The invention will now be described by a detailed description of several embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the true spirit or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

Reaction chamber

In a first aspect, the present invention relates to a reaction chamber. The reaction chamber of the first aspect may be a chamber in which a reaction can occur. Reference will now be made to Fig. 2. The reaction chamber 1 is adapted for containing a gas-porous separation entity 2 (see Fig. 2b) in such a way that said separation entity separates the chamber 1 in a first and a second unit 13, 14 by occupying the whole area of a section S (see Fig. 2a) of said reaction chamber. In embodiments of the present invention, the volume of the reaction chamber is not a limiting factor in the present invention.

In embodiments of the first aspect, said adaptation to accommodate said gas-porous separation entity may enable said gas-porous separation entity to occupy a section (S) (e.g. the whole area of said section (S)) of said reaction chamber.

In embodiments of the first aspect, said first unit and said second unit may be separate entities at least joined together via an opening (S13) in said first unit and an opening (S14) in said second unit, said reaction chamber comprising:

- said first unit for use as a gas inlet unit or as a gas outlet unit comprising:

(i) said opening (S 13),

(ii) said first gas port in addition to said opening,

(iii) said first aperture for allowing an electromagnetic radiation to traverse said first unit from said first aperture to said opening,

(iv) said first gas impermeable window, substantially transparent to at least part of the spectrum of said electromagnetic radiation, placed so as to prevent gas from escaping via said aperture,

- said second unit for use as a gas outlet unit if the first unit is a gas inlet unit or as a gas inlet unit if the first unit is a gas outlet unit comprising:

(i) said opening (S14),

(ii) said second gas port in addition to said opening,

(iii) said second aperture for allowing an electromagnetic radiation to traverse said second unit from said second opening to said second aperture, (iv) said second gas impermeable window, substantially transparent to at least part of the spectrum of said electromagnetic radiation, placed so as to prevent gas from escaping via said aperture,

wherein said first unit and said second unit are attached (or attachable) to each other by connecting said first opening with said second opening so as to form said reaction chamber.

This embodiment is advantageous because having the reaction chamber made of two attachable parts permits to open the chamber by separating said parts. This permits an easier cleaning or replacement of the porous separation entity. The attachment of both units can be performed via any suitable connection means permitting to attach both said units. For instance a male screw thread (e.g. integrated in the wall of the first unit) and a female screw threads (e.g. integrated in the wall of the second unit) can be used.

In embodiments of the first aspect, the reaction chamber may comprise either:

- means for holding said gas-porous separation entity in said way, or

- means for holding a part made of gas-porous material in such a way that said means and said part made of gas-porous material together form said gas-porous separation entity.

In embodiments of the first aspect, said first unit and/or said second unit comprise either:

- said means for holding said gas-porous separation entity in said way, or

- said means for holding said part made of gas-porous material in such a way that said means and said part made of gas-porous material together form said gas-porous separation entity.

In embodiments of the first aspect, the reaction chamber may comprise said gas- porous separation entity, said gas-porous separation entity being gas-porous by virtue of it being at least in part made of gas-porous material, and wherein said gas-porous material is at least partly transparent to said electromagnetic radiation.

In embodiments of the first aspect, said gas-porous material (22) may have photocatalytic properties. This is advantageous as a photocatalytic material makes the reaction chamber suitable for forming part of an air purification reactor.

In embodiments of the present invention, said gas-porous material may comprise titanium dioxide and preferably a nanoporous titanium dioxide foam. Titanium dioxide is photocatalytic and nanoporous titanium dioxide foams have a very large specific surface, thereby offering a large ratio between the amount of gas adsorbed on and in the material to the amount of non-adsorbed gas present in the optical path separating the emitter from the detector.

In embodiment of the first aspect of the present invention, said electromagnetic radiation may be an infrared radiation.

In embodiments of the first aspect, the windows may be situated so as to close said apertures. This permits a compact design while ensuring a gas tight chamber.

In embodiments of the present invention, the reaction chamber may further comprise at least one irradiation source, preferably a UV light source, preferably placed in at least one of a first and a second space separating said first or second window from said first or second aperture respectively (when this space exists, i.e. in the case where the windows are not situated so as to close said apertures. In this last case, the at least one irradiation source can be place for instance around the aperture, on the one or both end walls of the reaction chamber where the apertures are present ; also, in such a case, the window delimiting said space should not only be substantially transparent to at least part of the spectrum of said electromagnetic radiation but should also be substantially transparent to at least part (e.g. the part relevant for activating the porous material or for cleaning the porous material) of the output of the irradiation source).

The irradiation source can serve to activate the porous material when this material has photocatalytic properties. It can also be used to clean the porous material by degrading the adsorbed gas.

In embodiments of the first aspect, said at least one UV light source may be at least a first UV light source placed in said first space and a second UV light source placed in said second space.

In embodiments of the first aspect of the present invention, said at least one UV light sources may be adapted to trigger a photocatalytic activity in said gas-porous material.

In embodiments of the first aspect of the present invention, said gas-porous material may comprise absorbed and/or adsorbed species.

The volume of the reaction chamber may be selected as a function of the intended use of the chamber. If the chamber is intended to be used in combination with an FT-IR spectrometer by placing the chamber in the FT-IR sample compartment, the volume will be limited by the volume of said sample compartment. If the chamber is to be used with an emitter and a detector which are not part of a pre-existing device such as a FT-IR spectrometer, the volume of the chamber is in no way limited. In general, the reaction chamber will have a volume in the range of from 4. 10^" L to 9 L. The separation entity is gas-porous by virtue of it being at least in part made of gas-porous material 22. The separation entity 2 may be entirely made of gas-porous material 22 (see Fig. 2b) or partly made of gas-porous material 22 (see Fig. 2d).

For instance, in the case of a cylindrical chamber 1 when the separation entity 2 is entirely made of gas-porous material 22, the separation entity 2 can consist of a gas-porous disc 2 having the same diameter as the internal diameter of the chamber (see left side of Fig. 2b). In the example of a rectangular parallelepiped chamber 1, the separation entity can consist of a gas-porous rectangle having the same dimensions as a section S, e.g. the smallest section S, of the chamber 1 (see right side of Fig. 2b).

In an embodiment, the separation entity 2 is only in part made of gas-porous material 22. In such a case, the gas-porous material 22 preferably occupies a central part of the separation entity 2 (see Fig. 2d). For instance, the separation entity 2 can be formed of (i) a part made of gas-porous material 22 and (ii) means 21 for holding the part made of gas- porous material (see Fig. 2d).

As made clear hereabove, the reaction chamber of the first aspect of the present invention does not necessarily comprise the separation entity (and therefore the part made of porous material) but it is adapted to comprise said separation entity. The porous part of the separation entity can for instance be a sample to be analysed. In such a case, the reaction chamber can be manufactured and sold without the separation entity but it must be adapted to receive it. In other embodiments, the porous part of the separation entity can be made of a catalytic material and the reaction chamber can be used as an analytical tool (e.g. to analyse a gas or its reaction in contact with the catalytic material) or as a purification tool. In such a case, the reaction chamber can be manufactured and sold when comprising said catalytic material.

In embodiments, the adaptation can comprise the presence in the chamber 1 of means 21 for holding said separation entity 2 in place in such a way that said separation entity 2 separates the chamber in a first and a second unit 13, 14 by occupying the whole area of a section S of said reaction chamber 1. This embodiment is best represented in Fig. 1 and 3 wherein means 21 are shown. Means 21 can take various design as long as it has the ability to hold the separating entities in the way described above. For instance, the means 21 can take the shape of a relief running along at least part of the perimeter of said section of the chamber. This permits separation entities having a complementary relief on its edge to be held fixed in the chamber. Examples of relief are one or more grooves running along at least part of the perimeter of said section of the chamber.

Fig. 3 shows means 21 being two ring-shaped elements fixed to the internal entity of the reaction chamber. The separation entity can be held fixed in between said ring-shaped element.

This is also shown in Fig. 4 wherein the separation entity 2 is depicted sandwiched between two ring-shaped elements 21. Fig. 5 illustrates how the separation entity 2 can be easily placed and removed by using a reaction chamber 1 formed of multiple pieces which are mutually screwable together wherein one piece comprises one of said ring-shaped elements and a second piece, screwable together with the first piece, comprises the other of said ring shaped elements.

In other embodiments, the adaptation can comprise the presence in the chamber of means 21 for holding the part made of gas-porous material 22 in such a way that said means 21 and said part made of gas-porous material 22 together form said separation entity 2. This is illustrated in Fig. 2c and 2d.

The volume of the first unit 13 and the second unit 14 can be the same or different. Preferably, the volume of the first and the second units are the same. The reaction chamber further comprises an inlet for gas. It is placed in said first unit or in said second unit, in addition to said section S and therefore apart from the separation entity once in place.

The reaction chamber also further comprises an outlet for gas. It is placed in said second unit (or in said first unit if said inlet for gas is in said second unit), in addition to said section S and therefore in addition to the separation entity once in place.

Preferably, the reaction chamber does not comprise an outlet for gas and an inlet for gas in the same unit. The purpose of having the inlet in the first unit and the outlet in the second unit (or vice versa) is to force the gas through the porous material. The reaction chamber is gas-tight so that the gas introduced via the gas inlet cannot escape from the chamber via other means than the gas outlet.

The reaction chamber further comprises a first and a second aperture in both the first and the second unit respectively to enable an electromagnetic radiation to traverse said reaction chamber perpendicularly to said section and through said section. The apertures are positioned in the body of the reaction chamber, at the extremities of said chamber, so as to face each other separated by said section S. This is best shown in Fig. 4 (apertures 5 and 6). Both apertures are also visible in Fig. 3. One of the two apertures is visible in Fig. 6.

The first and second apertures are aligned with the foreseen or actual position of the part of the separation entity made of porous material in the reaction chamber.

The reaction chamber further comprises a first and a second gas-impermeable window substantially transparent to at least part of the spectrum of an analytically relevant electromagnetic radiation. The first and second gas-impermeable windows are preferably substantially transparent to at least the same part of the spectrum that the porous material is at least partly transparent to. The gas-impermeable windows can for instance be made of quartz, KBr CaF₂, BaF₂, ZnSe, NaCl, KC1 or Csl amongst others

The gas-impermeable windows are placed so as to prevent gas from escaping by said first and second apertures respectively. For instance, the gas impermeable windows can be situated so as to close said aperture. This can for instance be done by fitting the windows in the aperture (see Fig. 1), by fixing the windows on the external or internal wall at the extremity of the reaction chamber so as to cover and therefore close said aperture, or by occupying the whole area of another section of the reaction chamber, said other section being situated between the aperture, on one hand, and the inlet (or outlet) for gas on another hand, thereby being in addition to said aperture while preventing the gas from escaping. This last embodiment is best shown in Fig. 4.

The material used to form the walls of the reaction chamber is preferably a non- porous material. The material used to form the walls of the reaction chamber can be an organic material such as a polymer. Organic materials are not preferred when an irradiation source (e.g. a UV source) is present in the reaction chamber. Preferably, the material used to form the walls of the reaction chamber is an inorganic material such as a metal, a ceramic or a glass. The material is preferably chosen so that it does not interfere in the measurement by absorbing or adsorbing the gas to be measured. An inert material is therefore preferred. A non-catalytic and in particular a non-photocatalytic material is preferred. It can for instance be stainless steel or a glass (e.g. borosilicate glass, soda-lime glass or quartz amongst others).

The reaction chamber according to embodiments of the present invention may further comprise at least one irradiation source. This irradiation source comprised in the reaction chamber (e.g. comprised between the aperture and the gas-impermeable window) is not to be confused with the emitter of electromagnetic radiation situated outside the reaction chamber but in the reactor (e.g. as a part of a FT-IR spectrometer, said FT-IR spectrometer forming part of said reactor). In embodiments of the present invention, the purpose of the irradiation sources is to activate the gas-porous material if said gas-porous material has photocatalytic properties. The irradiation source can therefore be a UV light source adapted to trigger a photocatalytic activity in the gas-porous material. Typically, the irradiation sources irradiate in the range 200-800 nm and are preferably UV irradiation sources irradiating in the range 200 to 400 nm. Due to their small spatial requirements, LEDs are preferred irradiation sources. The number of irradiation sources can vary from 1 to many more. Preferably, an identical number of irradiation sources are present on both sides of said section S. When more than one irradiation source is present on one side of said section S, they preferably encircle the aperture. The number of irradiation sources on one side of the separation entity can for instance be from 1 to 20, preferably from 4 to 12, more preferably from 6 to 10 and for instance be 8.

The at least one irradiation source is preferably placed in at least one of a first and a second space (item 17 in Fig. 4) separating the first or second window from the first or second aperture respectively.

Fig. 3, 4, 5 and 6 will now be described in more detail.

Fig. 3 shows a cylindrical reaction chamber according to an embodiment of the present invention. Apertures 5 and 6 are depicted at the extremity of the cylinder. A gas- impermeable window is fitted in said apertures. An inlet for gas 3 and an outlet for gas 4 are also depicted. Means 21 for holding a separation entity are depicted as well. They consist of two ring shaped elements fixed to the internal wall of the cylinder.

Fig. 4 is a cross-section of a reaction chamber according to embodiments of the present invention. Fig. 5 is an exploded cross-sectional view of the same reaction chamber as shown in Fig. 4.

From left to right, Fig. 5 shows a first part comprising an aperture 6, a printed circuit 19 on which ultra-violet emitting LEDs 10 are connected. The printed circuit in glued to a stainless steel substrate. Also shown is a hole 20 for fitting an electrical connection for connecting said LEDs 10 to a power supply (not shown). This first part can be screwed to a second part which is a cylinder comprising a gas-impermeable window 9 occupying the whole internal area of a section of said cylinder. This second part can in turn be screwed to a third part, thereby creating the second unit 14, said third part comprising an outlet for gas 4 and a means 21 for holding a separation entity. The third part can in turn be screwed to a fourth part. The fourth part is similar to the third part but comprises the separation entity 2 in addition to a means 21 for holding said separation entity 2. Also an inlet for gas is present instead of an outlet for gas. Here, both the inlet and the outlet are only differentiated by their function since they are identical in structure. A fifth part can in turn be screwed to the fourth part, thereby creating the first unit 13. The fifth part is similar to the second part. Finally, a sixth part can be screwed to the fifth part, the sixth part being identical to the first part.

The fourth, fifth and sixth parts are labelled C, B and A in Fig. 6. Fig. 6 shows an embodiment of the present invention wherein an inlet for gas 3, an outlet for gas 4, an aperture 5 and a hole for fitting an electrical connection 20 are shown.

The cylindrical body of the second, third fourth and fifth parts are preferably made of stainless steel.

In an embodiment, the present invention relates to an in-situ FT-IR photocatalytic reactor.

Fig. 1 shows a reactor according to embodiments of the present invention. It comprises a cylindrical reaction chamber 1, an emitter 11 of electromagnetic radiation 7 and a detector 12 of electromagnetic radiation 7. The reaction chamber 1 shown comprises means 21 for holding a separation entity in such a way that said separation entity separates the chamber in a first and a second unit 13, 14. The chamber is further shown to comprise two apertures 5 and 6 each closed by a fitting window 8 and 9 respectively. The chamber is further shown to comprise an inlet for gas (3) and an outlet for gas (4).

Gas-porous material In an embodiment of the present invention, the gas-porous material has photocatalytic properties. When such is the case, the reaction chamber preferably also comprises one or more light sources adapted to provoke said photocatalytic properties.

In an embodiment of the present invention, the gas-porous material comprises titanium dioxide, preferably a titanium dioxide foam.

In an embodiment of the present invention, the gas-porous material is nanoporous.

Preferably, the gas-porous material comprises a nanoporous titanium dioxide foam.

The gas-porous material is at least partially transparent to at least part of the spectrum of an analytically relevant electromagnetic radiation. Reactor

In a second aspect, the present invention relates to a reactor comprising:

- a reaction chamber,

- an emitter of electromagnetic radiation, and

- a detector of said electromagnetic radiation for generating analytical data .

In an embodiment of the second aspect, the reactor may be according to any embodiments of the first aspect.

In embodiments of the second aspect, said emitter and detector may be part of an FT-

IR spectrometer e.g. a FT-IR in-situ reactor.

In embodiments of the second aspect, the emitter may be adapted to emit said electromagnetic radiation through said first aperture or said second aperture and said detector may be adapted to detect said electromagnetic radiation, as modified after passage through said gas-porous separation entity, through said second aperture or said first aperture respectively so as to permit detection in transmission. This is a particularly simple device.

In other words, said emitter may be present on one side of said section S and said detector may be present on the other side of said section S so as to permit detection in transmission.

In embodiments of the second aspect, said reactor may further comprise a control system for modifying the irradiation output from an irradiation source in function of said analytical data. This is for embodiments when the reaction chamber has at least one irradiation source such as a UV source. This is useful when the porous material has photocatalytic properties as it permits to modulate the irradiation output in function of the analytical data and therefore in function of the amount and/or the nature of the measured adsorbed chemical species. This permits the use of the reactor as a gas purifier, which does not consume more energy than necessary.

In embodiments of the second aspect, the reactor may further comprise means for creating a pressure difference between said first unit and said second unit. This facilitates the passage of the gas through the gas-porous separation entity.

Method of studying the interaction of a gas with a gas-porous material In a third aspect, the present invention relates to a method of studying the interaction of a gas with a gas-porous material comprising the steps of:

(i) in a reaction chamber according to any embodiment of the first aspect of the present invention wherein a gas-porous separation entity is present, introducing said gas into said reaction chamber 1 via said inlet for gas 3,

(ii) emitting said electromagnetic radiation 7 through said first aperture,

perpendicularly to said section S, and

(iii) detecting said electromagnetic radiation 7 through said second aperture.

In embodiments of the third aspect, the reaction chamber can be as in any embodiments of the first aspect.

Embodiments of the present invention comprising an irradiation source 10 (such as e.g. a UV light source) and a photocatalytic porous material can also be used for the purpose of purifying air.

In Fig. 7, an electromagnetic radiation 7 is passed through a reaction chamber 1 and detected, thereby generating analytical data 15. This data is provided to a control system 16 which acts on an irradiation source 10 to modulate its irradiation output 18 in function of said data 15. This system would permit to automatically adapt the irradiation output 18 in a photocatalytic purification system to the amount of pollutant present in the air.

In embodiments of the third aspect wherein said reaction chamber further comprises at least one irradiation source (e.g. a UV light source), the method may further comprise the step of irradiating said gas-porous material with said irradiation source before step (iii).

The following examples exemplify the use of a FT-IR in-situ reactor, according to the present invention, in-situ studies of photocatalytic process under atmospheric conditions.

EXAMPLE 1

An example of the third aspect, according to the present invention, is the use of an FT-IR study to investigate in-situ the photocatalytic degradation of nitric oxide [see B. Hauchecome et al., Infrared Physics & Technology, volume 53 (2010) pages 469-473, available online October 8, 2010).] Materials used in the experiment:

The catalyst used was the commercially available Aerolyst® 7710, a P25-based titania catalyst, supplied by EVONIK in pellet form. The pellets were pulverised in mortar and pestle to make disks. An amount of 120 mg powder per disk of 13 mm diameter was found to be the best combination. In order to enhance the optical properties of the disk, different percentages of KBr powder were added to the Ti0₂.

The NO gaseous stream was generated by mixing two different gases: NO (1% NO in N₂; Air Liquide) and air (21% 0₂ in N₂; Air Liquide). Both flows are controlled by Brooks mass flow controllers 5850E series, in the 0-200 mL min^"1 and 0-5 L min^"1 range respectively. Experiments were performed at room temperature, as measured with a Re^¬ type thermocouple inside the reactor: 24 + 2°C.

Methods:

By placing the disks in dedicated equipment with a gas flow, their gas permeability was assessed. With a pressure gauge the difference in pressure could be measured. If there was no pressure drop, the gases could flow through the disk without any problem. The disks were also tested on their visual integrity afterwards. The specific area of Aerolyst® 7710 and the disks were determined by the BET (Brunauer-Emmett-Teller) method through the nitrogen adsorption isotherms at -196°C. The volume and pore size distribution were calculated from the BET isotherms by the BJH method (Barret-Joyner- Halenda) in a Micromeritics® Tristar 3000 equipment.

To ensure that the used UV LEDs delivered enough energy for the photocatalytic reaction, the photolysis of N0₂ was measured, it being known that photolysis of N0₂ occurs at a wavelength lower than 420 nm [A. Kraus, A. Hofzumahaus, Field

measurements of atmospheric photolysis frequencies for 0₃, N0₂, HCHO, CH₃CHO, H₂0₂, and HONO by UV spectroradiometry, J. Atmos. Chem. 31 (1998) 161-180; C. Topaloglou, S. Kazadzis, A.F. Bais, M. Blumthaler, B. Schallhart, D. Balis, N0₂ and HCHO photolysis frequencies from irradiance measurements in Thessaloniki Greece, Atmos. Chem. Phys. 5 (2005) 1645-1653]. Using FT-IR spectroscopy the UV-photolysis of N0₂ to NO under UV LEDs irradiation was monitored at wavenumbers of 1602 cm^"1 and 1900 cm^"1 respectively. For this experiment, the FT-IR in-situ reactor was filled with a mixture of NO and N0₂. There was no catalyst in the reactor, so every change in the FTIR spectra was due to changing conditions in UV light from the LEDs. The actual NO degradation experiments were carried out in batch process, 5000 ppm NO was given in a total flow of 200 ccm (100 ccm air + 100 ccm NO) for 5 min after which the reactor was closed and placed in batch. IR spectra were scanned in the region 4000-600 cm^"1 at a resolution of 1 cm^"1 for all experiments. The spectra were recorded with a water correction, made possible by the delivered software (OMNIC® Thermo Fisher Scientific).

Results:

In order to test the IR transparency, several Aerolyst® 7710 disks were made with different KBr concentrations (0, 25, 42%). The spectra obtained are shown in Fig. 8a. It is clear that the self-supporting Ti0₂ disk gives the best results because more information can be found in these spectra. The spectrum showed less noise compared to higher KBr concentrations as shown in Fig. 8b. A strong broad band was found at 2700-3600 cm^"1 which could be assigned to surface Ti-OH [D.A. Panayotov, J. Yates, Depletion of conduction band electrons in Ti0₂ by water chemisorption-IR spectroscopic studies of the independence of Ti-OH frequencies on electron concentration, Chem. Phys. Lett. 410 (2005) 11-17]. The band at 1625 cm^"1 decreased with lower amount of Aerolyst® 7710, which indicates that this band can be assigned to the d(HOH) mode of chemisorbed H₂0 on Ti0₂ [see D.A. Panayotov et al.]. The self-supporting Ti0₂ disk gave no pressure drop and did not break during the test. The effect of the disk making process on the physical structure of the material was studied by measuring the surface area of Aerolyst® 7710, both in pellet form as in pulverised form, and a self-supporting disk. From these results, the volume and pore size distribution was calculated using the BJH method. The results are shown in Table 1.

Table 1:

These results show that there are some changes noticeable in the specific area of the disks compared to those of the untreated material. In fact, a higher specific area was measured. On the other hand, there was a shift in average pore size from 25 nm in the untreated form to 10 nm for the disk. There was no noticeable difference between the pulverised and the untreated photocatalyst. The changes were thus due to the disk making process itself and not the pulverisation step. The disks were pressed under a press load of 10 tons, which gives a high force on the photocatalyst leading to a collapse of the inner structure and thus a lower average pore volume and size.

The N0₂photolysis experiments clearly demonstrated that there was a decrease in N0₂ and an increase in NO upon irradiation with UV light from the UV-LEDs. A FT-IR study in real-time of the photocatalytic degradation of nitric oxide confirmed earlier research in this field.

EXAMPLE 2

An example of the third aspect, according to the present invention, is the use of an FT-IR study to investigate in-situ the photocatalytic degradation of ethylene. Materials used in the experiment:

The catalyst used was Aerolyst® 7710, a P25-based titania catalyst, supplied by EVONIK in pellet form. This catalyst was dried in N₂ at 300°C for 24 h. All experiments were carried out with 0.060 g catalyst, which was finely ground and pressed (2 tons) into a 13 mm porous disk.

The polluted gas flow was generated by mixing two gases: C₂H₄ (1% C₂H₄ in N₂; Air

Liquide) and air (21% 0₂ in N₂; Air Liquide). Both flows were controlled by Brooks mass flow controllers 5850E series, in the 0-200 mL min^"1 and 0.5 L min^"1 range respectively. Experiments were carried out at room temperature, 26 + 2 °C as measured with a K-type thermocouple inside the reactor. Methods used:

All experiments were carried out in batch. After a disk was made, it was placed in the FT-IR in-situ reactor and incorporated in the FT-IR spectrometer (Thermo Nicolet™ 6700; Thermo Fisher Scientific). A spectrum was always obtained before and after the experiment so that an analysis could be made of the adsorbed species that are still on the surface after the reaction. During the experiments, the IR spectra were scanned in the region 4000 to 600 cm^"1 at a resolution of 1 cm^"1 for all experiments. The spectra shown are made with a water correction, made possible by the delivered software (OMNIC®, Thermo Fisher Scientific).

The actual experiments were conducted as follows: after applying a gaseous stream of C₂H₄ for 10 to 15 minutes until a steady state was realised, the reactor was placed in batch and different IR bands were logged by using an automated data-logging device ("macro" from Thermo Fisher Scientific). After a stabilisation period of 1 h, the UV LEDs were turned on for about 2 to 3 h. After another stabilisation period of 1 h, the experiment was stopped.

For these experiments, different concentrations of ethylene were used, ranging from 5,000 to 10,000 ppm. The experiments at 10,000 ppm ethylene were performed in reducing conditions i.e. in the absence of added oxygen.

Adsorbed product spectroscopy was applied to obtain a clear view of the different IR bands caused by products adsorbed on the catalyst, For this, Aerolyst® 7710 was placed in different possible intermediates after which the product-impregnated Ti0₂ was prepared for placement in the reactor. A spectrum of the adsorption bands of the product on Ti0₂ could then be obtained. The possible intermediates for which such spectra were obtained were formaldehyde (37% solution Acros Organics), ethane- 1,2-diol (Sigma- Aldrich) and formic acid (VWR). If the tested product was indeed a possible intermediate, turning the UV lights on would then further degrade the adsorbed phase. In doing so further steps in the degradation process were revealed.

The pure products themselves were also measured by FT-IR spectroscopy. The method described by Vlachos et al. was used for this purpose [N. Vlachos, Y. Skopelitis, M. Psaroudaki, V. Konstantinidou, A. Chatzilazarou, E. Tegou, Anal. Chim. Acta 573-574 (2006) 459-465]. Briefly, the procedure can be described as follows: a droplet of the pure product is placed in between two KBr disks and a spectrum is then measured. By comparing the adsorbed phase spectra and the pure product spectra with the results from the FT-IR in-situ experiments, a better idea of the potential reaction pathway can be obtained.

Additionally, the method described by Vlachos et al. was slightly modified. Instead of using two KBr disks, one of the KBr disks was replaced by a Ti0₂ disk. This allowed us to follow the adsorption of the pure product throughout the adsorption process. When this process is followed in the FTIR spectrometer, the shifting of the different bands can be seen, giving a better indication of where the adsorbed bands are situated. Results:

The FT-IR in-situ reactor, according to the present invention, made it possible to determine the reaction pathway of photocatalytic ethylene degradation. It was found that the degradation occurred through the formation of two intermediates: formaldehyde and formic acid, for which formaldehyde is bound in two different ways (coordinatively and as bidentate). Finally C0₂ and H₂0 were formed, resulting in the complete mineralisation of the pollutant. The oxidising agent in this reaction appeared to be multiple OH-radicals.

The first step in the degradation pathway occurred through an electron shift from the molecular orbitals of ethylene. This is the first time that a hypothesis in this direction has been validated experimentally, which shows the power of such an in-situ reactor.

It is to be understood that although preferred embodiments, specific constructions and configurations, as well as materials, have been discussed herein for devices according to the present invention, various changes or modifications in form and detail may be made without departing from the scope and spirit of this invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention. For instance, instead of having the emitter and the detector at opposite sides of the chamber, the emitter and the detector can be placed at the same side of the device and a mirror is place at the other side of the device. This permits for instance to force the electromagnetic radiation to pass twice through said gas-porous substrate, thereby increase sensitivity.

Claims

1. A reaction chamber (1), said reaction chamber being adapted to accommodate a gas- porous separation entity (2) in such a way that said gas-porous separation entity (2) separates said chamber (1) into a first and a second unit (13, 14) so that said gas- porous separation entity (2) is the only pathway for gas between said first unit (13) and said second unit (14), said reaction chamber (1) comprising:

- a first gas port (3) in said first unit (13),

- a second gas port (4) in said second unit (14),

- a first aperture (5) in said first unit (13) and a second aperture (6) in said second unit

(14) for allowing said electromagnetic radiation (7) to traverse said reaction chamber (1) from said first aperture (5) to said second aperture (6), and

- a first and a second gas-impermeable window (8, 9), substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to provide the capability of preventing gas from escaping via said first and second apertures (5, 6) respectively.

2. The reaction chamber according to claim 1 wherein said adaptation to accommodate said gas-porous separation entity (2) enables said gas-porous separation entity to occupy a section (S) of said reaction chamber (1). 3. The reaction chamber according to claim 1 or claim 2, wherein said first unit (13) and said second unit (14) are separate entities at least joined together via an opening (S13) in said first unit and an opening (S14) in said second unit, said reaction chamber comprising:

- said first unit (13) for use as a gas inlet unit or as a gas outlet unit comprising:

(i) said opening (S13),

(ii) said first gas port (3) in addition to said opening (S13), (iii) said first aperture (5) for allowing an electromagnetic radiation (7) to traverse said first unit (13) from said first aperture (5) to said opening (S13),

(iv) said first gas impermeable window (8), substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to prevent gas from escaping via said aperture (5),

- said second unit (14) for use as a gas outlet unit if unit (13) is a gas inlet unit or as a gas inlet unit if unit (13) is a gas outlet unit comprising:

(i) said opening (S14),

(ii) said second gas port (4) in addition to said opening (S14),

(iii) said second aperture (6) for allowing an electromagnetic radiation (7) to traverse said second unit (14) from said second opening (S14) to said second aperture (6),

(iv) said second gas impermeable window (9), substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to prevent gas from escaping via said aperture (6),

wherein said first unit (13) and said second unit (14) are attached to each other by connecting said first opening (S13) with said second opening (S14) so as to form said reaction chamber (1).

The reaction chamber according to any one of the preceding claims comprising either:

- means (21) for holding said gas-porous separation entity (2) in said way, or

- means (21) for holding a part made of gas-porous material (22) in such a way that said means (21) and said part made of gas-porous material (22) together form said gas-porous separation entity (2).

The reaction chamber according to claim 4 as depending on claim 3 wherein said unit (13) and/or said unit (14) comprise either:

- said means (21) for holding said gas-porous separation entity (2) in said way, or

- said means (21) for holding said part made of gas-porous material (22) in such a way that said means (21) and said part made of gas-porous material (22) together form said gas-porous separation entity (2). he reaction chamber (1) according to any one of the preceding claims comprising said gas-porous separation entity (2), said gas-porous separation entity being gas-porous by virtue of it being at least in part made of gas-porous material (22), and wherein said gas-porous material (22) is at least partly transparent to said electromagnetic radiation (7). 7.- The reaction chamber (1) according to claim 6 wherein said gas-porous material (22) has photocatalytic properties.

8. - The reaction chamber (1) according to claim 7 wherein said gas-porous material (22) comprises titanium dioxide and preferably a nanoporous titanium dioxide foam.

9. - The reaction chamber (1) according to any one of the preceding claims wherein said electromagnetic radiation (7) is an infrared radiation.

10. - The reaction chamber (1) according to any one of claims 1 to 9, wherein said windows (8, 9) are situated so as to close said apertures (5, 6).

11. - The reaction chamber (1) according to any one of the preceding claims, further

comprising at least one irradiation source (10), preferably a UV light source (10), preferably placed in at least one of a first and a second space (17) separating said first or second window (8, 9) from said first or second aperture (5,6) respectively.

12. - The reaction chamber (1) according to claim 11, wherein said at least one UV light source (10) are at least a first UV light source (10) placed in said first space (17) and a second UV light source (10) placed in said second space (17).

13. - The reaction chamber (1) according to claim 11 or claim 12 as depending on claim, wherein said at least one UV light sources (10) are adapted to trigger a photocatalytic activity in said gas-porous material (22). 14.- The reaction chamber (1) according to any one of claims 6 to 13 wherein said gas- porous material (22) comprises absorbed and/or adsorbed species. A reactor comprising:

- a reaction chamber (1) according to any one of claims 1 to 14,

- an emitter (11) of electromagnetic radiation (7), and

- a detector (12) of said electromagnetic radiation (7) for generating analytical data

(15).

The reactor according to claim 15, wherein said emitter (11) and detector (12) are part of an FT-IR spectrometer.

The reactor according to claim 15 or claim 16, wherein said emitter (11) is adapted to emit said electromagnetic radiation (7) through said first aperture (5) or said second aperture (6) and said detector (12) is adapted to detect said electromagnetic radiation (7), as modified after passage through said gas-porous entity, through said second aperture (6) or said first aperture (5) respectively so as to permit detection in transmission.

18. - The reactor according to any one of claims 15 to 17 as depending on claim 11 wherein said reactor further comprises a control system (16) for modifying the output of said irradiation source (10) in function of said analytical data (15).

19. - The reactor according to any one of claims 15 to 18 further comprising means for creating a pressure difference between said first unit (13) and said second unit (14). 0.- A reactor comprising a reaction chamber (1), said reaction chamber being adapted to accommodate a gas-porous separation entity (2) in such a way that said gas-porous separation entity (2) separates said chamber (1) into a first and a second unit (13, 14) so that said gas-porous separation entity (2) is the only pathway for gas between said first unit (13) and said second unit (14), said reaction chamber (1) comprising:

- a first gas port (3) in said first unit (13),

- a second gas port (4) in said second unit (14),

and being further adapted to accommodate the transversal of said reaction chamber by an electromagnetic radiation,

- an emitter (11) of electromagnetic radiation (7), and a detector (12) of said electromagnetic radiation (7) for generating analytical data (15).

- A method of studying the interaction of a gas with a gas-porous material comprising the steps of:

in a reaction chamber (1) containing a gas-porous separation entity (2) in such a way that said gas-porous separation entity (2) separates said chamber (1) in a first and a second unit (13, 14) so that said gas-porous separation entity (2) is the only pathway for gas between said first unit (13) and said second unit (14), said reaction chamber (1) comprising:

- a first gas port (3) in said first unit (13), said first gas port being used as a gas inlet or a gas outlet,

- a first aperture (5) in the first unit (13) and a second aperture (6) in the second unit (14) for allowing an electromagnetic radiation (7) to traverse said reaction chamber (1) from said first aperture (5) to said second aperture (6), and

- a first and a second gas-impermeable window (8, 9), substantially transparent to at least part of the spectrum of said electromagnetic radiation (7), placed so as to prevent gas from escaping by said first and second apertures (5, 6) respectively,

(i) introducing said gas into said reaction chamber (1) via said first gas port (3) or said second gas port (4),

(ii) emitting said electromagnetic radiation (7) through and from said first or second aperture (5, 6) to said second or first aperture (6, 5) respectively, and

(iii) detecting said electromagnetic radiation (7) through said second or first aperture (6, 5) respectively. - A kit of part for assembling a reaction chamber (1) according to claim 1, comprising: - a first unit (13) comprising:

(i) an opening (S13),

(ii) said first gas port (3) in addition to said opening S13, (iii) said first aperture (5) for allowing an electromagnetic radiation (7) to traverse said first unit (13) from said first aperture (5) to said first opening (S13) or from said first opening (S13) to said first aperture (5),

- a second unit (14) comprising:

(i) a second opening (S14),

(ii) said second gas port (4) in addition to said opening S14,

(iii) said second aperture (6) for allowing an electromagnetic radiation (7) to traverse said second unit (14) from said aperture (6) to said opening (S14) or from said first opening (S14) to said first aperture (6),

wherein said first unit (13) and said second unit (14) are adapted to be attachable to each other by connecting said first opening (S13) with said second opening (S14) so as to form said reaction chamber (1). 23.- A first or second unit for assembling a reaction chamber (1) according to claim 1, comprising:

(i) an opening (SI 3 or S14),

(ii) a gas port in addition to said opening (SI 3 or SI 4),