HYDROGEN SENSITIVE FILM, HYDROGEN SENSOR AND PREPARATION THEREOF

Abstract

A hydrogen sensitive film, a hydrogen sensor and a preparation thereof. The hydrogen sensitive film has a composite structure of an aerogel and a catalyst. The aerogel can adsorb hydrogen and undergo hydrogenation reaction with hydrogen. The catalyst is a nano-noble metal catalyst for catalyzing the hydrogenation reaction, and is distributed in pores of the aerogel. The hydrogen sensitive film is prepared by mixing a catalyst into an aerogel through physical compounding. The hydrogen sensor includes an insulating substrate layer, the hydrogen sensitive film and an electrode layer.

Claims

1. A hydrogen sensitive film, wherein the hydrogen sensitive film has a composite structure formed by an aerogel and a catalyst; the aerogel is configured for hydrogen adsorption and hydrogenation reaction with hydrogen; and the catalyst is a nano-structured noble metal catalyst for catalyzing the hydrogenation reaction, and is distributed in pores of the aerogel.

2. The hydrogen sensitive film of claim 1, wherein a pore size of the aerogel is 50-100 nm; and a particle size of the catalyst is 5-20 nm.

3. The hydrogen sensitive film of claim 1, wherein a thickness of the aerogel is 500 nm-5 mm.

4. The hydrogen sensitive film of claim 1, wherein a weight ratio of the aerogel to the catalyst is (50-300):1.

5. The hydrogen sensitive film of claim 1, wherein the aerogel is selected from the group consisting of a titanium dioxide (TiO.sub.2) aerogel, a stannic oxide (SnO.sub.2) aerogel, a cadmium oxide (CdO) aerogel, a cerium dioxide (CeO.sub.2) aerogel, an iron oxide (Fe.sub.2O.sub.3) aerogel, a nickel oxide (NiO) aerogel, a zinc oxide (ZnO) aerogel, an indium(III) oxide (In.sub.2O.sub.3) aerogel and a gallium(III) oxide (Ga.sub.2O.sub.3) aerogel.

6. The hydrogen sensitive film of claim 1, wherein the catalyst is nano-palladium (Pd) catalyst or nano-platinum (Pt) catalyst.

7. A method for preparing a hydrogen sensitive film, comprising: mixing a catalyst particle into a metal oxide aerogel through physical compounding.

8. The method of claim 7, wherein the physical compounding is performed through steps of: mixing the metal oxide aerogel with the catalyst particle followed by grinding to obtain a mixed powder; and adding deionized water to the mixed powder followed by grinding to obtain a slurry; wherein a weight ratio of the metal oxide aerogel to the catalyst particle is (50-300):1; and a weight ratio of the deionized water to the mixed powder is (5-15):1.

9. A hydrogen sensor, comprising: an insulating substrate layer; the hydrogen sensitive film of claim 1; and an electrode layer.

10. The hydrogen sensor of claim 9, wherein a thickness of the electrode layer is 20-200 nm.

11. A hydrogen sensor, comprising: an insulating substrate layer; a hydrogen sensitive film; and an electrode layer; wherein the hydrogen sensitive film is prepared by the method of claim 7.

12. The hydrogen sensor of claim 11, wherein a thickness of the electrode layer is 20-200 nm.

13. A method for preparing a hydrogen sensor, comprising: (a) mixing an aerogel and a catalyst in water to obtain a slurry; (b) coating the slurry onto an upper surface of an insulating substrate layer at a desired thickness followed by drying to obtain an aerogel coating; and (c) preparing an electrode layer on a surface of the aerogel coating to obtain the hydrogen sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present disclosure will be more apparent and understandable with reference to the accompanying drawings. The accompanying drawings form a part of the disclosure, but are not intended to limit the disclosure.

[0041] FIG. 1A is a side view of a plate-shaped hydrogen sensor according to an embodiment of the disclosure;

[0042] FIG. 1B is a top view of the plate-shaped hydrogen sensor according to an embodiment of the disclosure;

[0043] FIG. 2 is a side view of a rod-shaped hydrogen sensor according to an embodiment of the disclosure;

[0044] FIG. 3 schematically depicts an aerogel of the hydrogen sensor according to an embodiment of the disclosure;

[0045] FIG. 4 schematically depicts a Pd particle-loaded aerogel of the hydrogen sensor according to an embodiment of the disclosure;

[0046] FIG. 5 is a scanning electron microscope (SEM) image of a hydrogen sensor according to Example 1 of the disclosure;

[0047] FIG. 6 schematically depicts a structure of the aerogel according to an embodiment of the disclosure;

[0048] FIG. 7 illustrates a response of the hydrogen sensor prepared in Example 1 at room temperature under different hydrogen concentrations; and

[0049] FIG. 8 illustrates a response of the hydrogen sensor prepared in Embodiment 2 at room temperature under different hydrogen concentrations.

[0050] In the drawings: 1, insulating substrate layer; 2, hydrogen sensitive film; and 3, electrode layer.

DETAILED DESCRIPTION OF EMBODIMENTS

[0051] The present disclosure will be described in detail below with reference to the embodiments and accompanying drawings to make objects, technical solutions and advantages of the present disclosure more apparent and understandable. Obviously, described below are merely illustrative, and are not intended to limit the disclosure.

Example 1

[0052] Provided herein was a hydrogen sensor, which was prepared through the following steps.

[0053] (S1) Preparation of TiO.sub.2 Aerogel

[0054] A TiO.sub.2 aerogel with uniform and regular pores was prepared through supercritical drying, where the obtained TiO.sub.2 aerogel had a specific surface area of 1600 m.sup.2/g, a density of 35 kg/m.sup.3, a porosity of 99%, and a pore size of 50 nm. The prepared TiO.sub.2 aerogel was schematically depicted in FIGS. 3 and 6.

[0055] (S2) Preparation of TiO.sub.2 Aerogel-Pd Slurry

[0056] After annealed, the TiO.sub.2 aerogel was mixed with Pd powder (particle size: 8 nm) in a mortar in a weight ratio of 60:1 and ground to obtain a mixed powder, which was dropwise added with deionized water and ground evenly to obtain a slurry, where a weight ratio of the deionized water to the mixed powder was 6:1.

[0057] (S3) Preparation of Aerogel Coating

[0058] The slurry was uniformly coated on a quartz substrate 1, and dried at 80° C. to obtain an aerogel coating. Such process was repeated until a thickness of the aerogel coating 2 reached 500 nm. The microscopic structure of the Pd particle-loaded TiO.sub.2 aerogel was schematically depicted in FIGS. 4-5.

[0059] (S4) Preparation of Electrode

[0060] Pt electrodes 3 were deposited on two ends of a surface of the aerogel coating 2 to form effective electrical contact with the aerogel coating, where a thickness of the Pt electrode layer was 30 nm (as shown in FIGS. 1A-B).

[0061] The hydrogen sensor prepared herein, which consisted of an insulating substrate layer 1, a hydrogen sensitive film 2 and an electrode layer 3, was tested for the hydrogen sensitivity, and the results demonstrated that the hydrogen sensor exhibited great sensitivity at room temperature. Specifically, the sensitivity of the hydrogen sensor reached 97.8% under a hydrogen content of 1.6 vol %, and the hydrogen sensor had a response time of 2 s and a restoring time of 10 s (as shown in FIG. 7).

Example 2

[0062] Provided herein was a hydrogen sensor, which was prepared through the following steps.

[0063] (S1) Preparation of TiO.sub.2 Aerogel

[0064] A TiO.sub.2 aerogel with uniform and regular pores was prepared through supercritical drying, where the obtained TiO.sub.2 aerogel had a specific surface area of 1600 m.sup.2/g, a density of 35 kg/m.sup.3, a porosity of 99%, and a pore size of 50 nm.

[0065] (S2) Preparation of TiO.sub.2 Aerogel-Pd Slurry

[0066] After annealed, the TiO.sub.2 aerogel was mixed with Pd powder (particle size: 20 nm) in a mortar in a weight ratio of 230:1 and ground to obtain a mixed powder, which was dropwise added with deionized water and ground evenly to obtain a slurry, where a weight ratio of the deionized water to the mixed powder was 12:1.

[0067] (S3) Preparation of Aerogel Coating

[0068] The slurry was uniformly coated on a surface of a polytetrafluoroethylene (PTFE) rod 1 (length: 5 cm, diameter: 10 mm), and dried at 80° C. to obtain an aerogel coating. Such process was repeated until a thickness of the aerogel coating 2 reached 2 mm.

[0069] (S4) Preparation of Electrode

[0070] Pt electrodes 3 were deposited on two ends of a surface of the aerogel coating 2 to form effective electrical contact with the aerogel coating. A thickness of the Pt electrode layer was 160 nm (as shown in FIG. 2).

[0071] The hydrogen sensor prepared herein was tested for the hydrogen sensitivity, and the results demonstrated that the hydrogen sensor exhibited great sensitivity at room temperature. Specifically, the sensitivity of the hydrogen sensor reached 98.2% under a hydrogen content of 1.6 vol %, and the hydrogen sensor had a response time of 1.7 s and a restoring time of 8 s (as shown in FIG. 8).

[0072] Described above are only some embodiments of the present disclosure, which are not intended to limit the disclosure. It should be understood that any variations, replacements and improvements made by those of ordinary skilled in the art without departing from the spirit of the disclosure should fall within the scope of the disclosure defined by the appended claims.