A NEW TYPE OF THERMAL CATALYTIC OXIDATION MATERIAL FOR AIR PURIFICATION AND APPARATUS THEREFORE

Abstract

The invention provides an air purifier (1) comprising a catalytic converter (100), the catalytic converter (100) comprising (i) a catalytically active material (120) and (ii) a heatable material (130) in thermal contact with said catalytically active material (120), wherein the heatable material (130) is heatable by one or more of an alternating electrical field and an alternating magnetic field, the air purifier (1) further comprising a field generator (140), configured free from electrical contact with the heatable material (130) and configured to heat during operation of the air purifier (1) the heatable material (130) by one or more of the alternating electrical field and the alternating magnetic field.

Claims

1. An air purifier comprising: a catalytic converter, wherein the catalytic converter comprises a multifunctional material that is the combination of at least: a catalytically active material; and a heatable material, wherein the heatable material is heatable by one or more of an alternating electrical field and an alternating magnetic field; and a field generator, configured free from electrical contact with the multifunctional material and configured to heat during operation of the air purifier the heatable material by one or more of the alternating electrical field and the alternating magnetic field, wherein one or more of the catalyically active material and the heatable material are independently configured as one or more of (i) particularly material, (ii) a layer, and (ii) a wire, and wherein independently the one or more of (i) the particulate material, (ii) the layer, and (iii) the wire have at least one dimension of 50 μm or less.

2. The air purifier according to claim 1, further comprising a porous material, wherein the multifunctional material comprises the combination of the catalytically active material, the heatable material and the porous material.

3. The air purifier according to claim 1, wherein the catalytically active material is configured to abate one or more of (i) volatile organic compounds (VOCs), (ii) ozone (O3), (iii) NOx, and (iv) particulate material in air.

4. The air purifier according to claim 1, wherein the multifunctional material comprises a particulate material mixture which comprises particles including at least the catalytically active material and the heatable material.

5. The air purifier according to claim 4, wherein the particulate material comprises particles including a core comprising said heatable material and a shell comprising said catalytically active material.

6. The air purifier according to claim 4, wherein the particulate material further comprises a porous material.

7. (canceled)

8. The air purifier according to claim 7, wherein the catalytic converter comprises a layered structure, comprising at least a layer comprising said catalytically active material and a layer comprising said heatable material.

9. The air purifier according to claim 1, wherein the heatable material is configured in physical contact with said catalytically active material.

10. The air purifier according to claim 1, further comprising a gas flow generator configured to bring air in contact with the catalytically active material.

11. The air purifier according to claim 1, further comprising a sensor configured to sense a molecule in air, and a control unit, wherein the control unit is configured to control the field generator as function of a sensor signal of the sensor and a predetermined level of said molecule.

12. The catalytic converter as defined in claim 1.

13. A method for the abatement of a convertible compound in air, the method comprising using the air purifier according to claim 1 contacting in a contacting stage said air with the catalytically active material while at least temporarily subjecting the heatable material to one or more of an alternating electrical field and an alternating magnetic field before the contacting stage and/or during at least part of the contacting stage.

14. An air purifier as claimed in claim 1, wherein independently the one or more of (i) the particulate material, (ii) the layer, and (iii) the wire have at least one dimension of 10 μm or less, for example 10 μm or less, for example 100 nm or less.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0038] FIGS. 1a-1b schematically depict some aspects of the air purifier;

[0039] FIGS. 2a-2g schematically depict some aspects of the catalytic converter;

[0040] FIG. 3 schematically depicts an embodiment of the air purifier;

[0041] FIG. 4 shows TEM images of (a) magnetic iron oxide nanoparticles (˜110 nm), (b) MnO2 nanoparticles (˜20-30 nm), (c) EMT-zeolite nanoparticles (˜15 nm);

[0042] FIG. 5 shows TEM and SEM images of (a) magnetic iron oxide nanoparticles (22 nm), (b) MnO.sub.2 nanoparticles (˜25 nm), (c) MnO.sub.2 nanotubes (diameter: 100 nm, wall thickness: 30 nm, length: several microns), (d) EMT-zeolite nanoparticles(˜15 nm);

[0043] FIG. 6 shows TEM images of (a) porous MnO), molecular sieve (K-OMS-2), (b) magnetic iron oxide nanoparticles (˜110 nm); and

[0044] FIG. 7 shows TEM and SEM images of (a) porous magnetic iron oxide nanoparticles (>100 nm), (b) MnO2 nanoparticles (˜25 nm).

[0045] The schematic drawings are not necessarily on scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] FIGS.. 1a-1b schematically depict embodiments of an air purifier 1 comprising a catalytic converter 100. The catalytic converter 100 comprises a catalytically active material 120 and a heatable material 130 in thermal contact with said catalytically active material 120. Further, the heatable material 130 is heatable by one or more of an alternating electrical field and an alternating magnetic field, indicated with reference 141. The air purifier 1 thereto further comprises a field generator 140, especially configured free from electrical contact with the heatable material 130, but at least configured to heat during operation of the air purifier 1 the heatable material 130 by one or more of the alternating electrical field and the alternating magnetic field 141. Reference F indicates a gas flow (i.e. especially an air flow).

[0047] Reference 300 indicates a gas flow generator (configured to generate gas flow F) and references 400 and 500 indicate a sensor and control unit, respectively. These may be integrated in the air purifier or may be configured separate thereof. The air purifier 1 and the sensor 400 and the control unit 500 are especially functionally coupled to each other (e.g. in an integrated device or as system). The dashed line in FIG. 1a may indicate a housing, which may include the field generator and which may at least partly enclose the catalytic converter 100.

[0048] FIG. 1b schematically depicts a variant with a gas flow generator 300 included in the air purifier 1. To this end, the air purifier 1 may include a chamber enclosing the gas flow generator 300 and the catalytic converter 100 and the field generator 140.

[0049] In this invention, we propose a series of—amongst others—new multi functional TCO materials for air purification. In the new materials, a novel localized heating is realized through material engineering. The material structure design may—amongst others —be based on the material function, size and shape. FIGS. 2a-2g schematically illustrate a number of possible structures of the catalytic converter, without being exhaustive, with reference 120 indicated in the catalytic material, reference 130 indicating the heatable material, and reference 200 indicating the porous material, and with references d1, d2 and d3, indicating a dimension of these functional materials, respectively, especially in these examples their thicknesses. Reference 11 indicates particles and reference 10 indicates particulate material (comprising these particles 11).

[0050] In FIG. 2a, a random blending structure is shown. The abovementioned three functional materials may be mixed, and optionally the materials may thereafter be granulated into desired size and shape. Hence, the functional materials may be mixed as particulate materials, and be used as such, or may be further granulated, to provide composite particles. In FIG. 2a, by using commercial products, iron powders (or magnetic iron oxide powders) as heating generation materials (FIG. 4a.), zeolite powders as porous materials (FIG. 4c.), MnO), powders as TCO materials (FIG. 4b.), and mixing them together with stable binders (e.g. bentonite) and granulation into desired particles, and then calcining the granulated particles at high temperature (e.g. 200-500° C.) to activate the porous materials and TCO catalysts.

[0051] Also core/shell structures may be provided, see e.g. FIG. 2b, with the core being indicated with reference 12 and the shell(s) being indicated with reference 13. For instance by using heating generation materials as core, TCO catalyst as intermediate shell, and porous materials as outer shell. The core size and shell thickness can be controlled with the accuracy of nanometer, and even with atomic-scale precision (FIG. 2b).

[0052] Also heterostructures may be provided, such as sandwich structure, with e.g. a TCO catalyst as intermediate layer, and the heating generation material and porous materials as outer layers. The thickness of each layer can be controlled with the accuracy of nanometer, and even with atomic-scale precision. Two variants are schematically depicted in FIGS. 2c and 2d, with reference 15 indicating a layer.

[0053] Also hybrids, alloys or heterostructure may be provided, for instance by using porous MnO.sub.x as both porous materials and TCO materials, and then combine with magnetic materials (FIG. 2e) or by using porous FeO.sub.x as both porous materials and magnetic materials, and then combine with TCO materials (FIG. 20f).

[0054] In some of the above embodiments, also the porous material 200 is included. As mentioned above, this functional material is optional.

[0055] FIG. 2g schematically depicts an embodiment of catalytic converter 100, with a layer 15 of the heatable material 130 and thereon wires 16 and particles 11 comprising the catalytically active material 120.

[0056] FIG. 3 schematically depicts an embodiment of the catalytic converter 100, including an enlargement of part thereof. Thereof catalytic converter 100 comprises a wire gauze comprising the heatable material 130. On the wires 16 of the wire gauze the catalytically active material 120 may be applied as particles 11. Alternatively or additionally, the particles 11 comprises heatable material 130 (see also above). When the heatable material comprises magnetic material, the magnetism may also be used to adhere the particles to an iron or otherwise magnetic support, such as here the wires 16.

[0057] FIG. 4 shows TEM images of (a) magnetic iron oxide nanoparticles (˜110 nm), (b) MnO.sub.2 nanoparticles (˜20-30 nm), (c) EMT-zeolite nanoparticles (˜15 nm).

[0058] FIG. 5 shows TEM and SEM images of (a) magnetic iron oxide nanoparticles (22 nm), (b) MnO, nanoparticles (˜25 nm), (c) MnO.sub.2 nanotubes (diameter: 100 nm, wall thickness: 30 nm, length: several microns), (d) EMT-zeolite nanoparticles(˜15 nm). The heterostructure designs are more flexible, and the synthesis methods are similar to core/shell structure. For example, sandwich structure (FIG. 2c), similar sized magnetic iron oxide nanoparticles (FIG. 5a) and porous zeolite materials (FIG. 5d) can epitaxy growth on the opposite crystal faces of MnO.sub.2 nanoparticles (FIG. 5b). By using larger sized MnO.sub.2 nanotubes (FIG. 5c), smaller sized magnetic iron oxide nanoparticles (FIG. 5a) and porous zeolite materials (FIG. 5d) can be loaded on the nanotubes surface or filled into nanotubes.

[0059] FIG. 6 shows TEM images of (a) porous MnOx molecular sieve (K-OMS-2), (b) magnetic iron oxide nanoparticles (˜110 nm). In FIG. 2e, for example, by using porous MnOx molecular sieve (K-OMS-2) (FIG. 6a) as both porous materials and TCO materials, and then combine with magnetic iron oxide nanoparticles (FIG. 6b).

[0060] FIG. 7 shows TEM and SEM images of (a) porous magnetic iron oxide nanoparticles (>100 nm), (b) MnO.sub.2 nanoparticles (∞25 nm). In FIG. 2f, for example, by using porous magnetic Fe.sub.2O.sub.3 (FIG. 7a) as both porous materials and magnetic materials, and then combine with MnO.sub.2 (FIG. 7b) TCO materials.

[0061] Hence, herein we propose amongst others new types of multifunctional TCO materials for air purification. The multifunctional TCO materials are the combination and integration of at least two types of functional materials: heat generation materials, catalysts, such as TCO catalysts, and optionally porous materials. The heat generation materials can generate and confine the heat within a space down to nanoscale. The will be transferred to nearly contacted TCO catalyst unit directly and consumed with high efficiently. The heat may substantially not diffuse into the environment, which is energy saving and safety. Porous Material can capture and concentrate organic pollutant gases (e.g. VOCs) from the airstream, which will increase the contacting and reaction time with TCO catalyst. The material structures design are flexible, such as random blending structure, core/shell structure, heterostructure and alloyed structure, which may be based on the material function, size and shape. Parts of structures may be combined with magnetic materials, so they can be absorbed on the iron substrate (e.g. iron mesh) automatically and robustly, which may simplify the coating process significantly.

[0062] Above, many examples are described in relation to TCO catalysts. However, in other embodiments equally well other catalysts may be applied, as indicated above.