TWI706126B - Gas sensing device and gas sensing system - Google Patents

Abstract

A gas sensing device comprises a housing, a cover body, and a gas sensing module. The housing has an accommodation space. The cover body is disposed on the housing. The cover body has a top surface, a bottom surface, and a gas passage. The bottom surface faces the accommodating space. The gas passage is connected to the accommodating space. The gas passage has a first opening and a second opening. The first opening is located on the top surface. The second opening is located on the bottom surface. The area of the first opening is larger than the area of the second opening. A gas sensing system comprises two aforementioned gas sensing devices, and one of the gas sensing devices is provided with a filter module.

Description

Gas sensing device and gas sensing system

The present invention relates to a gas sensing device and a gas sensing system, in particular to a gas sensing device and a gas sensing system with enhanced gas diffusion capability.

In environments where humans live and in environments where explosions, fires, or toxicity may occur, gas sensing devices are needed to detect the concentration of potentially dangerous target gases. The gas sensing device must have the sensitivity to reliably respond to the concentration and changes of target gases such as carbon monoxide, nitrogen oxide, sulfur dioxide, hydrogen sulfide, carbon dioxide, hydrogen, phosphine, and ozone.

The sensing mechanism of the current gas sensor is that the ambient airflow enters the gas sensor in a natural diffusion manner. However, the gas flowing through the area around the gas sensor is susceptible to poor air diffusivity or environmental gas field, which makes the amount of gas to be measured entering the gas sensor insufficient, resulting in the sensitivity and accuracy of the gas sensor As a result, the gas sensor cannot be used to detect low-concentration target gases in the environment.

The present invention is to provide a gas sensing device and a gas sensing system. The cover has a structure in which the diameter of the second opening is smaller than the diameter of the first opening to adjust the local flow field around the cover to increase the flow through the first opening. The second opening enters the gas amount of the gas sensing device.

The gas sensing device disclosed in the present invention includes a housing, a cover, and a gas sensing module. The shell has an accommodation space. The cover is arranged on the shell. The cover has a top surface, a bottom surface and a gas channel. The bottom surface faces the accommodating space. The gas channel communicates with the accommodating space. The gas channel has a first opening and a second opening. The first opening is located on the top surface. The second opening is located on the bottom surface. The area of the first opening is larger than the area of the second opening. The gas sensing module is arranged in the containing space.

The gas sensing system disclosed in the present invention includes a carrier, a first gas sensing device, and a second gas sensing device. The first gas sensing device is arranged on the carrier. The first gas sensing device has the structure of the aforementioned gas sensing device. The second gas sensing device is arranged on the carrier. The second gas sensing device has the structure of the aforementioned gas sensing device. The second gas sensing device further includes a filter module. The filter module includes a fixed structure and a selective filter material. The fixing structure is arranged on the cover and located in the accommodating space. The selective filter material is arranged in the fixed structure, and the selective filter material shields the second opening.

The present invention is to provide a gas sensing device. The cover has a structure in which the diameter of the second opening is smaller than that of the first opening to adjust the local flow field around the cover to increase the gas entering through the first and second openings. The gas volume of the sensing device. In this way, as the amount of gas entering the gas sensing device increases, the sensitivity and accuracy of the gas sensing device of the present invention for detecting gas concentration can also be improved.

The above description of the content of the disclosure and the description of the following embodiments are used to demonstrate and explain the spirit and principle of the present invention, and to provide a further explanation of the patent application scope of the present invention.

The detailed features and advantages of the present invention are described in detail in the following embodiments, and the content is sufficient to enable anyone familiar with the relevant art to understand the technical content of the present invention and implement it accordingly, and according to the content disclosed in this specification, the scope of patent application and the drawings Anyone who is familiar with the relevant art can easily understand the related purpose and advantages of the present invention. The following examples further illustrate the viewpoints of the present invention in detail, but do not limit the scope of the present invention by any viewpoint. In the following and in the drawings, similar elements are represented by the same symbols.

Please refer to FIG. 1A, FIG. 1B and FIG. 2. FIG. 1A is a cross-sectional view of the gas sensing device according to the first embodiment of the present invention. FIG. 1B is a partially enlarged view of the gas sensing device according to the first embodiment of the present invention. Fig. 2 is a perspective view of the gas sensing device according to the first embodiment of the present invention. As shown in FIG. 1A, the gas sensing device 10 of the first embodiment of the present invention includes a housing 15, a cover 11 and a gas sensing module 12. The housing 15 has an accommodation space 150. The cover 11 is arranged on the housing 15.

In the first embodiment of the present invention, the housing 15 is cylindrical. In other embodiments, the housing 15 may have a square column shape, a polygonal column shape, or the like. The structural dimensions of the housing 15 and the cover 11 are only examples. For example, in FIG. 1A, they are cylindrical structures with wider left and right widths, and the present invention is not limited to this.

In the first embodiment of the present invention, the cover 11 includes a top surface 110, a bottom surface 112 and a gas channel 111. The bottom surface 112 faces the accommodating space 150, and the gas channel 111 communicates with the accommodating space 150. The gas channel 111 has a first opening 1101 and a second opening 1102. The first opening 1101 is located on the top surface 110, and the second opening 1102 is located on the bottom surface 112. In detail, the gas channel 111 further has a slope surface 113, a wall surface 114 and a third opening 1103. One side of the slope surface 113 is connected to the top surface 110, and the opposite side of the slope surface 113 is connected to one side of the wall surface 114. The third opening 1103 is located at the junction of the slope surface 113 and the wall surface 114. One side of the wall surface 114 away from the slope surface 113 is connected to the bottom surface 112. The center of the bottom surface 112 is the second opening 1102 communicating with the accommodating space 150. In other words, the bottom surface 112 is parallel to the horizontal plane and expands around the second opening 1102, but not limited to this. In other embodiments of the present invention, the second opening 1102 may not be located at the center of the bottom surface 112, and the bottom surface 112 may not be parallel to the horizontal plane. The diameter D2 of the second opening 1102 may be equal to or smaller than the diameter D3 of the third opening 1103 (D2≦D3). In the embodiment of FIG. 1A, the diameter D2 is equal to the diameter D3. In some embodiments, when the diameter D2 is smaller than the diameter D3, the wall surface 114 presents a slope surface.

Please refer to FIG. 2. As shown in FIG. 2, the cover 11 has a top surface 110, a first opening 1101, and a second opening 1102. The area of the first opening 1101 is larger than the area (cross-sectional area of the horizontal plane) of the second opening 1102. The diameter D2 of the second opening 1102 is smaller than the diameter D1 of the first opening 1101 (D2>D1). Furthermore, the orthogonal projection of the center of the second opening 1102 on the first opening 1101 overlaps the center of the first opening 1101, so the cover 11 has an inverted cone or V-shaped slope structure. The angle θ between the slope surface 113 and the horizontal plane is 14 degrees. In other embodiments, the angle between the slope surface 113 and the horizontal plane may be 14 degrees to 42 degrees. That is, the intersection O of any two normal lines L1 and L2 on the slope surface 113 is located in the direction Z of the casing 15 toward the cover 11, and this intersection O is located outside the casing 15 (shown in FIG. 15). Returning to FIG. 1A, the cover 11 has a structure in which the diameter D2 of the second opening 1102 is smaller than the diameter D1 of the first opening 1101 to adjust the local flow field around the cover 11 to increase the passage through the first opening 1101 and the second opening. 1102 The amount of gas entering the accommodating space 150 of the gas sensing device 10.

In the first embodiment of the present invention, the shape of the top surface 110, the first opening 1101, the second opening 1102, and the third opening 1103 are circular. In other embodiments, the shape of the top surface 110, the first opening 1101, the second opening 1102, and the third opening 1103 may be quadrilateral, polygonal, or other geometric shapes such as ellipse, trapezoid, square, rectangle, etc.

In the first embodiment of the present invention, as shown in FIGS. 1A and 1B, the gas sensing module 12 includes a working electrode 1200, a first auxiliary electrode 1201, a reference electrode 1202, a second auxiliary electrode 1203, and a first spacer 122, the second spacer 123, the third electrolyte moisture absorption membrane 124, the fourth electrolyte moisture absorption membrane 125, the electrolyte 127, and the electrolyte tank 121. The working electrode 1200, the first auxiliary electrode 1201, the reference electrode 1202, and the second auxiliary electrode 1203 are collectively referred to as the electrochemical sensing electrode 120. The working electrode 1200 is disposed between the second opening 1102 and the first auxiliary electrode 1201. The first spacer 122 is located between the working electrode 1200 and the first auxiliary electrode 1201, and the first spacer 122 is electrically connected to the working electrode 1200 and the first auxiliary electrode 1201 (here, electrically connected by the first electrolyte to absorb moisture The electrolyte 127 absorbed by the membrane 122-1 is reached. The electrolyte (electrolyte) contained in the electrolyte 127 can generate free ions and conduct electricity in an aqueous solution. The first spacer 122 includes the first electrolyte moisture absorption membrane 122-1 And the first waterproof membrane 122-2. The second spacer 123 is located between the first auxiliary electrode 1201 and the reference electrode 1202, and the second spacer 123 is electrically connected to the first auxiliary electrode 1201 and the reference electrode 1202, and the second spacer 123 includes a second electrolyte moisture absorption film 123-1 and the second waterproof membrane 123-2. The third electrolyte moisture absorption film 124 is located between the second auxiliary electrode 1203 and the reference electrode 1202. The third electrolyte moisture absorption film 124 is used to electrically connect the second auxiliary electrode 1203 and the reference electrode 1202. The fourth electrolyte moisture absorption membrane 125 is provided between the second auxiliary electrode 1203 and the electrolyte tank 121. The electrolyte 127 is contained in the electrolyte tank 121. The electrolyte tank 121 is filled with a moisture-absorbing film (not shown). The top surface of the electrolyte tank 121 exposes a moisture-absorbing film for connection with the second auxiliary electrode 1203. In general, the electrochemical sensing electrode 120 is located on the electrolyte tank 121 and is physically and electrochemically connected to each other. In other embodiments, the first auxiliary electrode 1201 and the second spacer 123 may not be included. Through the above-mentioned working electrode 1200 and the first auxiliary electrode 1201, respectively, the current value and the voltage value independently provided by telecommunications are provided, and the concentration of the target gas in the gas to be measured can be obtained through calculation by the microprocessor.

In the first embodiment of the present invention, as shown in FIG. 1A, the working electrode 1200 includes a metal material and a porous material. The metal material can be a ternary composite metal or a monoatomic metal. The ternary composite metal or monoatomic metal is carried on the porous material, and the porous material is used as the carrier. In other embodiments, the porous material is carried on the hydrophobic polymer sheet. In one embodiment, the porous material has a zero-dimensional (particle or atom) or two-dimensional nanostructure. The porous material can be a porous material composed of carbon, such as a micron-sized carbon support, graphene, and doped graphite. Alkene (doped graphene, doped with elements such as nitrogen or phosphorus or boron), multi-walled carbon nanotube (multi-walled carbon nanotube), single-walled carbon nanotube (single-walled carbon nanotube), etc. In one embodiment, the structure of the ternary composite metal is a nanowire structure, and the ternary composite metal nanowire is a core-shell structure, one metal is the core, and the other two metals sequentially cover the core, the ternary composite Metal nanowires are scattered on porous materials. The ternary composite metal is selected from the group consisting of any three metals consisting of platinum, palladium, cobalt, silver, tin, copper, nickel, gold, and ruthenium, such as metals Platinum cobalt silver (PtCoAg), platinum tin silver (PtSnAg), platinum palladium nickel (PtPdNi), etc. In one embodiment, one or more monoatomic metals are dispersed on the porous material, and the monoatomic metals include any one of platinum, palladium, cobalt, silver, tin, copper, nickel, gold, and ruthenium. In one embodiment, the structure of the working electrode 1200 includes a porous material and metal particles composed of a single metal material carried on the porous material. The particle size of the metal particles is about 1Å or monoatomic metal particles. The metal particles include a plurality of single metal particles scattered on the porous material, and the plurality of single metal particles may be composed of the same metal element. The metal element can be selected from any metal selected from platinum, palladium, cobalt, silver, tin, copper, nickel, gold, and ruthenium. In another embodiment, the metal particles include multiple and plural kinds of monometallic particles, which are composed of different kinds of monoatomic metal particles, that is, at least two monometallic particles are dispersed on the porous material. The metal element is selected from at least two of the group consisting of platinum, palladium, cobalt, silver, tin, copper, nickel, gold, and ruthenium, for example: gold atoms and silver atoms interspersed or gold atoms and cobalt atoms interspersed, platinum Atoms and nickel atoms, copper atoms and cobalt atoms, gold atoms and copper atoms, etc.

Since the size of nanowires or monoatomic structures is at the nanometer level, they have a larger surface area, so the faster the reaction rate for redox. Therefore, the working electrode 1200 formed of a ternary composite metal or a monoatomic structure metal containing nanowires can improve the sensing sensitivity and accuracy of the gas sensing device 10, and has a low concentration detection limit (ppb level). The function.

In the first embodiment of the present invention, the material of the first auxiliary electrode 1201 is the same as that of the working electrode 1200. The second auxiliary electrode 1203 includes a conductive material such as porous carbon material or platinum (Pt). The reference electrode 1202 includes conductive materials such as silver chloride (AgCl), mercury chloride (HgCl ₂ ), and carbon platinum (Pt/C). In other embodiments, the first auxiliary electrode 1201, the reference electrode 1202, and the second auxiliary electrode 1203 may be carried on different hydrophobic polymer sheets, respectively.

In the first embodiment of the present invention, as shown in FIG. 1B, the first spacer 122 includes a first electrolyte moisture absorption membrane 122-1 and a first waterproof membrane 122-2. The first electrolyte moisture absorption membrane 122-1 is disposed between the working electrode 1200 and the first waterproof membrane 122-2. The second spacer 123 includes a second electrolyte moisture absorption film 123-1 and a second waterproof film 123-2. The second electrolyte moisture absorption membrane 123-1 is disposed between the first auxiliary electrode 1201 and the second waterproof membrane 123-2. In other embodiments, the second waterproof membrane 123-2 may be disposed between the two second electrolyte moisture absorption membranes 123-1. The first waterproof membrane 122-2 and the second waterproof membrane 123-2 are stable and impermeable polymers. The first electrolyte moisture absorption membrane 122-1 to the fourth electrolyte moisture absorption membrane 125 are used to ensure that the working electrode 1200, the first auxiliary electrode 1201, the reference electrode 1202, and the second auxiliary electrode 1203 are in contact with the electrolyte. The first electrolyte moisture-absorbing membrane 122-1, the second electrolyte moisture-absorbing membrane 123-1, the third electrolyte moisture-absorbing membrane 124 to the fourth electrolyte moisture-absorbing membrane 125 are hydrophilic non-conductive materials permeable by electrolyte 127 production. The structure of each electrolyte moisture-absorbing membrane is a porous structure or a fabric structure, which functions to transport the electrolyte 127 through capillary phenomena (please refer to FIG. 9, and the details will be further described in the relevant paragraphs below). Each electrolytic solution moisture-absorbing membrane absorbs the electrolytic solution 127 from the electrolytic solution tank 121, thereby maintaining the wet state of each electrolytic solution moisture-absorbing membrane containing the electrolyte.

In the first embodiment of the present invention, as shown in FIGS. 1A and 1B, the bottom center of the electrolyte tank 121 is provided with an opening 1210, and a plug 126 is matched and inserted into the opening 1210 to fill the electrolyte tank 121 After the electrolyte 127, the electrolyte tank 121 is sealed. The electrolyte 127 in the electrolyte tank 121 follows the direction T and passes through the upper and lower channels 16 through the fourth electrolyte moisture absorption membrane 125, the second auxiliary electrode 1203, the third electrolyte moisture absorption membrane 124, and the reference electrode in sequence 1202, a second spacer 123, a first auxiliary electrode 1201, a first spacer 122, and a working electrode 1200. The passage 16 has a moisture-absorbing film as a wick, which functions to transport the electrolyte 127 through capillary phenomenon. The electrolyte tank 121 is located at the bottom of the casing 15. The electrolyte 127 provided by the electrolyte tank 121 may include liquid electrolytes such as sulfuric acid, perchloric acid, and ionic liquid.

In the first embodiment of the present invention, the filter module 13 shown in FIG. 1A includes a fixed structure 130 and a selective filter material 135. The fixing structure 130 is disposed on the cover 11 and located in the accommodating space 150. The selective filter material 135 is disposed in the fixing structure 130, and the selective filter material 135 covers the second opening 1102. The selective filter material 135 includes two sheets and metal oxides, and the sheet has a large number of holes for gas to pass through. The sheet is a hydrophobic porous polymer membrane, such as PTFE, PVDF, etc. The metal oxide is disposed between the two sheets (for example, sandwiched between the two sheets) to cover the second opening 1102, as shown in FIG. 2.

The selective filter material 135 includes a metal oxide and a hydrophobic polymer membrane as an adhesive. The metal oxide includes a one-dimensional nanostructure having a β or γ crystal phase. The metal oxide includes manganese dioxide (MnO ₂ ), manganese trioxide (Mn ₂ O ₃ ), trimanganese tetraoxide (Mn ₃ O ₄ ), or manganese oxyhydroxide (MnOOH). For example, metal oxides include β-MnO ₂ nanowires and γ-MnOOH nanowires. Therefore, the selective filter material 135 containing the aforementioned manganese dioxide, dimanganese trioxide, trimanganese tetraoxide or manganese oxyhydroxide (MnOOH) can be used to remove ozone (O ₃ ) in the gas to be measured. Since the size of the metal oxide is of the nanometer level, it has a larger surface area, so that the metal oxide has a better removal efficiency when removing the interfering gas in the gas to be measured.

The particle size of the hydrophobic polymer can range from 40 μm to 700 μm. The hydrophobic polymer may include perfluoroalkylate (PFA), polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF).

In the first embodiment of the present invention, the selective filter material 135 composed of a hydrophobic polymer combined with a metal oxide has holes. Therefore, when the gas to be measured passes through the selective filter material 135, the interference gas is absorbed and decomposed by the selective filter material 135, and other gases can enter the accommodating space 150 through the holes of the selective filter material 135. As shown in FIG. 1A, in the first embodiment of the present invention, the gas sensing device 10 may include a filter module 13 for removing interference gas, but it is not limited to this. In other embodiments, if it is not necessary to remove the interfering gas that would interfere with the measurement result first, the gas sensing device 10 may not include the filter module 13 for removing the interfering gas.

In the first embodiment of the present invention, the gas sensing device 10 further includes conductive structures 14-1 to 14-4. One end of the four conductive structures 14-1 to 14-4 is arranged outside the housing 15, and the conductive structure 14 -1~14-4 can be regarded as pins, and the other ends are electrically connected to the working electrode 1200, the first auxiliary electrode 1201, the reference electrode 1202, and the second auxiliary electrode 1203, respectively. The working electrode 1200 is connected to the conductive structure 14 by wires -1; the first auxiliary electrode 1201 is connected to the conductive structure 14-2; the reference electrode 1202 is connected to the conductive structure 14-3; the second auxiliary electrode 1203 is connected to the conductive structure 14-4. The electrochemical sensing electrode 120 of the gas sensing device 10 obtains the power required to detect the concentration of the target gas from the outside through the four conductive structures 14-1 to 14-4, and transmits the current generated by the electrochemical reaction to the micro A processor (not shown) to calculate the target gas concentration. The calculated gas concentration can be provided to the user for reference via an external display device (not shown).

Since the oxidation potentials of nitrogen dioxide (NO ₂ ) and ozone (O ₃ ) are very similar, when the concentration of nitrogen dioxide or ozone is sensed, nitrogen dioxide and ozone will interfere with each other and affect the measurement accuracy. Therefore, in the first embodiment of the present invention, as shown in FIG. 1A, in order to separate nitrogen dioxide and ozone, the interfering gas removed by the filter module 13 is ozone, and ozone is removed to improve the sensing of the gas sensing system The accuracy of nitrogen dioxide concentration. The aforementioned gas sensing device 10 is an example when the gas to be measured contains ozone. In other embodiments, specific gases such as carbon monoxide, carbon dioxide, nitrogen oxides, sulfur oxides, nitrogen hydrides, ammonia hydrides, phosphorus hydrides, sulfur hydrides, arsenic hydrides, and boron hydrides When alcohol, aldehyde, hydrogen are unsaturated or saturated hydrocarbon vapor or halogenated hydrocarbon, you can choose to use the corresponding metal oxide and the corresponding electrolyte to design the specific gas sensing device 10.

Please refer to FIGS. 3-12. FIG. 3 is a cross-sectional view of the gas sensing device according to the second embodiment of the present invention. FIG. 4 is an exploded view of the gas sensing device according to the second embodiment of the present invention. FIG. 5 is a perspective view of the gas sensing device according to the second embodiment of the present invention. FIG. 6 is a schematic diagram of the cover according to the second embodiment of the present invention. FIG. 7 is a schematic diagram of the filter module according to the second embodiment of the present invention. FIG. 8 is a cross-sectional view of the gas sensing module according to the second embodiment of the present invention. FIG. 9 is a schematic diagram illustrating the laminated explosion of the gas sensing module 64 according to the second embodiment of the present invention. Fig. 10 is a schematic diagram of the upper seat of the inner container according to the second embodiment of the present invention. Fig. 11 is a schematic diagram of the lower seat of the inner container according to the second embodiment of the present invention. Fig. 12 is a schematic diagram of a housing drawn according to a second embodiment of the present invention.

As shown in FIGS. 3 to 5, the gas sensing device 60 of the second embodiment of the present invention includes a cover 61, an upper inner container base 62, a lower inner container base 63, a gas sensing module 64, a housing 65, and a filter mold. Group 66. The gas sensing module 64 and the filter module 66 are arranged between the cover 61 and the upper inner container base 62, the inner container upper seat 62 is arranged above the inner container lower seat 63, and the inner container lower seat 63 is arranged on the inner container upper seat 62 and the shell体65 between. In another embodiment, the gas sensing device 60 may not include the filter module 66. FIG. 4 is an exploded view of the gas sensing device 60 according to the second embodiment of the present invention. The cover 61 and the shell 65 are combined to form the outermost shell. The upper inner container base 62 and the lower inner container base 63 are fixed to each other by the first fastener 625 and the second fastener 631, and an electrolyte tank 121 is formed in the hollow to seal The member 634 prevents electrolyte leakage. The gas sensing module 64 is located between the upper inner container 62 and the filter module 66, and the filter module 66 is fixed on the bottom surface 112 of the cover 61. In particular, the gas sensing module 64 and the electrolyte tank 121 are separated by the upper inner container 62, and only the communication port 624 penetrates the two parts. Fig. 5 is a perspective view of the gas sensing device 60 according to the second embodiment of the present invention. The cover 61 and the housing 65 are combined to form the outermost housing. The diameter D2 of the cover 61 with the second opening 1102 is smaller than The diameter D1 of the first opening 1101 and the structure of the slope surface 113 can enhance the air flow from the outside into the gas sensing device 60. The filter module 66 shields the second opening 1102 to filter external air and adsorb specific gases.

As shown in FIG. 3, in the second embodiment of the present invention, there is an accommodation space 650 between the housing 65 and the cover 61. The upper inner container base 62, the lower inner container base 63, the gas sensing module 64 and the filter module 66 are located in the accommodating space 650. The structures of the cover 61, the housing 65 and the filter module 66 in the second embodiment are similar to the structures of the cover 11, the housing 15 and the filter module 13 in the first embodiment, so they will not be described in detail. 6 is a schematic diagram of the cover 61 according to the second embodiment of the present invention. The diameter D2 of the second opening 1102 is smaller than the diameter D1 of the first opening 1101 (D2>D1).

As shown in FIG. 7, in the second embodiment of the present invention, the fixing structure 130 of the filter module 66 has a plurality of holes for air circulation, and the selective filter material 135 is clamped in the holes by the fixing structure 130 . The fixing structure 130 is disposed between the cover 61 and the gas sensing module 64. The material of the filter module 66 in the second embodiment is similar to that of the filter module 13 in the first embodiment, so it will not be repeated.

As shown in FIGS. 8 and 9, the cross-sectional view of the gas sensing module 64 and the schematic diagram of the laminated explosion of the gas sensing module 64 in the second embodiment of the present invention are shown in the schematic diagram of the laminated explosion of the gas sensing module 64 , It only shows the stacking relationship of each layer, the size of each layer is only for illustration, not limited to this. The gas sensing module 64 of the second embodiment of the present invention is similar in structure to the gas sensing module 12 of the first embodiment, so the similarities will not be repeated. The gas of the second embodiment will be further described with reference to FIGS. 8 and 9 below. Sensing module 64. In the gas sensing module 64, the hydrophobic polymer layer 1200A is arranged between the working electrode 1200 and the filter module 66 (for example, the working electrode 1200 made of carbon black is arranged facing down), and the hydrophobic polymer layer 1201A is arranged on the first Between a waterproof membrane 122-2 and the first auxiliary electrode 1201 (for example, the first auxiliary electrode 1201 made of carbon black is arranged facing down), the hydrophobic polymer layer 1202A is disposed on the reference electrode 1202 and the third electrolyte to absorb moisture Between the membranes 124 (such as the configuration of the reference electrode 1202 made of carbon black facing up), the hydrophobic polymer layer 1203A is arranged between the third electrolyte moisture absorption membrane 124 and the second auxiliary electrode 1203 (such as carbon black) The second auxiliary electrode 1203 is arranged facing down). The second spacer 123 also includes a fifth electrolyte moisture absorption membrane 123-3 disposed between the second waterproof membrane 123-2 and the reference electrode 1202. The gas sensing module 64 also includes four electrode lines (not shown) corresponding to the working electrode 1200, the first auxiliary electrode 1201, the reference electrode 1202, and the second auxiliary electrode 1203, respectively. A first electrode wire 131 (not shown) corresponding to one of the working electrodes 1200 is disposed between the working electrode 1200 and the first electrolyte moisture absorption film 122-1, and the first electrode wire 131 is electrically connected to the working electrode 1200. A second electrode line 132 (not shown) corresponding to one of the first auxiliary electrodes 1201 is disposed between the first auxiliary electrode 1201 and the second electrolyte moisture absorption film 123-1, and the second electrode line 132 is connected to the first auxiliary electrode 1201. The electrode 1201 is electrically connected. A third electrode line 133 (not shown) corresponding to one of the reference electrodes 1202 is provided between the reference electrode 1202 and the fifth electrolyte moisture absorption film 123-3 of the second spacer 123, and the third electrode line 133 is connected to the reference The electrode 1202 is electrically connected. A fourth electrode line 134 (not shown) corresponding to one of the second auxiliary electrodes 1203 is disposed between the second auxiliary electrode 1203 and the fourth electrolyte moisture absorption film 125, and the fourth electrode line 134 and the second auxiliary electrode 1203 Electrical connection. The first waterproof membrane 122-2, the hydrophobic polymer layer 1201A, and the second waterproof membrane 123-2 each have a first through hole 1221, a second through hole 1201B, and a third through hole 1231, and the first through hole 1221, the second through hole 1231 The through holes 1201B and the third through holes 1231 are respectively filled with a first through hole moisture absorption film 1222, a second through hole moisture absorption film 12011, and a third through hole moisture absorption film 1232. The above-mentioned through-hole moisture absorption film system can transfer the electrolyte 127 to different levels.

As shown in FIG. 10, in the second embodiment of the present invention (FIG. 3), the upper inner container 62 has an upper groove 620, a separation layer 621 and a lower groove 622, and the separation layer 621 is disposed on the upper groove 620 and the lower groove Between 622, a plurality of support blocks 626 support the separation layer 621, and the support blocks 626 enhance the structural rigidity. The gas sensing module 64 is disposed in the upper groove 620 of the upper base 62 of the inner container. The edge of the upper groove 620 has a plurality of notches 623, and the separation layer 621 has a communication opening 624. A first fastener 625 is provided on the surface of the lower groove 622. The first electrode wire 131 to the fourth electrode wire 134 respectively pass through the plurality of notches 623, extend downward along the outer edge of the upper inner container base 62 and the outer edge of the lower inner base 63, and then are connected to the four conductive structures 14- 1~14-4. The communication port 624 of the separation layer 621 allows the electrolyte 127 in the electrolyte tank 121 to move the electrolyte 127 to the fourth part of the gas sensing module 12 through the capillary phenomenon of the adsorbent (not shown) passing through the communication port 624. The electrolyte moisture absorption membrane 125, as shown in FIG. 1B, the electrolyte 127 in the electrolyte tank 121 follows the direction T, and supplements the electrolyte 127 to each electrolyte moisture absorption membrane by passing through the upper and lower channels 16.

As shown in FIG. 11, in the second embodiment of the present invention (FIG. 3), the inner container lower seat 63 includes a lower seat upper slot 630, and a second fastener 631 for matching and securing with the first fastener 625. And a raised structure 632. The second fastener 631 is located on the surface of the upper groove 630 of the lower base facing the upper base 62 of the inner container. The upper groove 630 of the lower seat has a sealing hole 633. The electrolyte 127 is injected into the upper groove 630 of the lower seat through the sealing hole 633 from the outside, and the sealing hole 633 is sealed by a sealing member 634. The space enclosed by the upper inner container seat 62 and the lower inner container seat 63 is an electrolyte tank 121. The lower groove 622 of the upper inner container seat 62 and the upper groove 630 of the lower inner container lower seat 63 match and can be connected into one body.

As shown in FIG. 12, in the second embodiment of the present invention (FIG. 3), the bottom of the housing 65 has four conductive holes 651 and openings for combining with the raised structure 632 of the lower base 63 of the inner container 652. The 4 conductive holes 651 respectively correspond to the 4 conductive structures 14-1 to 14-4 that can be inserted.

Please refer to Figures 13A and 13B. Figures 13A and 13B are the covers 11|, 61 and shells 15, 65 used in the first embodiment (Figure 1A) and the second embodiment (Figure 3) of the present invention The flow field distribution diagram of the cover and the shell used in the comparative example. The air velocity in the flow field distribution ranges from 0.4 m/s to 0.6 m/s. The airflow is natural wind. The direction of air flow is from right to left (as indicated by the arrow). The length of the arrow represents the size of the airflow, longer arrows represent stronger airflow, and shorter arrows represent weaker airflow. As shown in FIG. 13A, the cover 11, 61 has a structure in which the diameter D2 of the second opening 1102 is smaller than the diameter D1 of the first opening 1101 and the slope surface 113, when the airflow flows through the gas sensing device 10 from right to left At 60 o'clock, convection phenomenon A can be generated inside and outside the second opening 1102 without an external fan. Furthermore, the central part of the fixed structure 130 makes the air flow disturbance into the accommodating space 150, 650 present a swirling distribution B (surrounding the central part of the fixed structure 130), so that the air flow is further directed toward the air in the accommodating space 150, 650 The movement of the measuring modules 12 and 64 further enhances the effect of convection phenomena. In other embodiments, the central part of the fixing structure 130 may not be provided. Therefore, the gas sensing device 10, 60 has a structure in which the diameter D2 of the second opening 1102 is smaller than the diameter D1 of the first opening 1101 by the cover 11, 61, thereby enhancing the local flow field around the gas sensing device 10, 60, thereby Enhance the diffusion ability of airflow. In contrast, as shown in Figure 13B, the cover of the gas sensing device of the comparative example has a non-slope structure, so that part of the airflow flows out at the opening, and there is no convection phenomenon C (the arrow at the opening) Shorter). Therefore, the gas entering the gas sensing device is mainly diffused. It can be seen from Fig. 13B that the gas flow disturbance is relatively static, so the mass transfer effect is poor. From the results of FIGS. 13A and 13B, it is confirmed that when the cover 11, 61 has a structure in which the diameter D2 of the second opening 1102 is smaller than the diameter D1 of the first opening 1101 and the slope surface 113, the part around the cover 11, 61 can be adjusted 13A, the second opening 1102 has a better convection phenomenon. In addition, the air flow turbulence entering the accommodating space 150, 650 presents a swirling distribution B due to the central part of the fixed structure 130, thereby increasing the passage through the first The amount of gas entering the gas sensing devices 10 and 60 through the opening 1101 and the second opening 1102. In contrast, the airflow in the opening of FIG. 13B is in a static state C.

Please refer to FIG. 14, which is an SEM image of a selective filter material 135 composed of a combination of metal oxide and hydrophobic polymer. As shown in FIG. 14, the metal oxides with a one-dimensional nanostructure of β or γ crystal phase are combined into a whole through a hydrophobic polymer to form a selective filter material 135. The mixing ratio of metal oxide and hydrophobic polymer can be 1:5 to 1:10 (weight ratio).

The following describes the influence of the ratio (weight ratio) of the metal oxide to the hydrophobic polymer in the selective filter material 135 of the filter module 13 of the present invention on the filtering effect of the selective filter material 135. In the first embodiment of the present invention, the ratio of the metal oxide MnO ₂ and the hydrophobic polymer PTFE is shown in Table 1 below.

Table 1 H1 (625 μm for PTFE) H2 (350μm for PTFE) H3 (44 μm for PTFE) MnO2: PTFE Removal efficiency MnO2: PTFE Removal efficiency MnO2: PTFE Removal efficiency MnO2 micron spherical particles (control group) 1:5 82% 1:5 82% 1:5 83% MnO2 micron spherical particles (control group) 1:10 83% 1:10 82% 1:10 85% MnO2 micron spherical particles (control group) 1:15 63% 1:15 60% 1:15 68% β-MnO2 Nanowire (Example) 1:5 93% 1:5 95% 1:5 96% β-MnO2 Nanowire (Example) 1:10 95% 1:10 96% 1:10 100% β-MnO2 nanowire 1:15 75% 1:15 76% 1:15 84% γ-MnOOH: PTFE Removal efficiency γ-MnOOH: PTFE Removal efficiency γ-MnOOH: PTFE Removal efficiency γ-MnOOH nanowire (example) 1:5 74% 1:5 76% 1:5 78% γ-MnOOH nanowire (example) 1:10 80% 1:10 81% 1:10 83% γ-MnOOH nanowire 1:15 62% 1:15 63% 1:15 65%

As shown in Table 1, the sizes of the hydrophobic polymer PTFE are 625 μm (H1), 350 μm (H2), and 44 μm (H3). The mixing ratio of metal oxide MnO ₂ and hydrophobic polymer PTFE is 1:5, 1:10 or 1:15. Compared with the selective filter material 135 composed of β-MnO ₂ nanowires and hydrophobic polymer PTFE in some embodiments of the present invention of 1:5 or 1:10, the selective filter material composed of MnO ₂ micron spherical particles For the control group. The ozone removal efficiency of the selective filter material 135 formed by the ratio of β-MnO ₂ nanowire and hydrophobic polymer PTFE of 1:5 or 1:10 is greater than 90%. The ratio of β-MnO ₂ nanowire and hydrophobic polymer PTFE is 1:15, and the ozone removal efficiency of selective filter material 135 is greater than 75%. The ratio of β-MnO ₂ nanowire and hydrophobic polymer PTFE is 1:5 or 1:10, and the ozone removal efficiency of the selective filter material 135 is better than that of the selective filter material formed by MnO ₂ micron spherical particles. In one embodiment, when the selective filter material 135 uses a mixture ratio of γ-MnOOH nanowire and hydrophobic polymer PTFE at a ratio of 1:10, the ozone removal efficiency is greater than 80%. In one embodiment, when the selective filter material 135 uses a mixture ratio of γ-MnOOH nanowire and hydrophobic polymer PTFE at a ratio of 1:5, the ozone removal efficiency is greater than 70%. In a preferred embodiment, the selective filter material 135 is composed of β-MnO ₂ nanowires and hydrophobic polymer PTFE in a mixing ratio of 1:10 (removal efficiency reaches 100%). β-MnO ₂ nanowires and γ-MnO ₂ nanowires have larger adsorption area and adsorption efficiency (compared to granular). At this time, the removal efficiency of interference gas (ozone) is greater than 99%. Furthermore, from the results of the size of the hydrophobic polymer PTFE and the removal efficiency of ozone, it can be seen that the smaller the size of the hydrophobic polymer PTFE, the better the removal efficiency of ozone.

Please refer to FIG. 15, which is a schematic diagram of a gas sensing system 50 according to a third embodiment of the present invention. As shown in FIG. 15, the gas sensing system 50 of the third embodiment of the present invention includes a carrier 20, a first gas sensing device 30 and a second gas sensing device 40. The first gas sensing device 30 is disposed on the carrier 20. The second gas sensing device 40 is disposed on the carrier 20. The structure of the first gas sensing device 30 and the second gas sensing device 40 of the third embodiment of the present invention is similar to the gas sensing device 10 of the first embodiment (FIG. 1A) or the gas sensing device of the second embodiment 60 (Figure 3), so the same points will not be repeated, and only the differences will be described below. That is to say, the first gas sensing device 30 and the second gas sensing device 40 in FIG. 15 are illustrated using the gas sensing device 10 of the first embodiment as an example, but the gas sensing device of the third embodiment The first gas sensing device 30 and the second gas sensing device 40 in the system 50 can be replaced with the gas sensing device 60 of the second embodiment (not shown), and the second gas sensing device 40 includes a filter module 13. The following description takes the gas sensing device 10 of the first embodiment as an example, but it is not limited thereto.

In the third embodiment of the present invention, the carrier 20 may be a printed circuit board (PCB) plastic substrate. The first gas sensing device 30 does not include a filter module, and the second gas sensing device 40 includes a filter module 13.

In the third embodiment of the present invention, a circuit (not shown), a microprocessor (not shown), and a power supply device (not shown) are further included. The power supply device may be a battery. The gas sensing system 50 uses a low-noise circuit for data collection, a microprocessor to calculate the data collected from the first gas sensing device 30 and the second gas sensing device 40, and the calculated data using visual Software to perform numerical display to determine the concentration of at least one analyte (such as NO ₂ and/or O ₃ ). The gas sensing system 50 may also include temperature detection and/or humidity detection elements.

The following describes the gas detection process of the gas sensing system 50 of the third embodiment of the present invention. In the third embodiment of the present invention, since the first gas sensing device 30 does not include a filter module, the detectable concentration of the gas to be measured will include the concentration of interference gas that can be removed by the filter module. On the other hand, since the second gas sensing device 40 includes the filter module 13, the concentration of the detected gas to be measured will not include the concentration of the interfering gas removed by the filter module, but the target gas is detected concentration. By subtracting the concentration of the target gas detected by the second gas sensing device 40 from the concentration of the gas to be measured detected by the first gas sensing device 30, the interference gas removed by the filter module can be obtained concentration. Therefore, the gas sensing system 50 of the third embodiment of the present invention has a sensing function of accurately sensing the concentration of the interference gas and the concentration of the target gas.

For example, the gas to be measured detected by the first gas sensing device 30 includes nitrogen dioxide and ozone (R1=[NO ₂ ]+[O ₃ ]). The gas to be measured detected by the second gas sensing device 40 contains nitrogen dioxide (R2=[NO ₂ ]), but does not contain ozone (adsorbed by the filter module 13). In other words, the second gas sensing device 40 can detect the concentration of the target gas nitrogen dioxide. By subtracting the total concentration of nitrogen dioxide and ozone detected by the first gas sensing device 30 from the concentration of nitrogen dioxide detected by the second gas sensing device 40, the concentration of ozone can be obtained ( R1-R2=[NO ₂ ]+[O ₃ ]-[NO ₂ ]=[O ₃ ]). That is, the signal deduction method is adopted to obtain the concentration signal of the target gas.

Please refer to FIG. 16. FIG. 16 is a concentration detection diagram of the second gas sensing device 40 including the filter module 13 of the present invention. The horizontal axis is time (seconds), and the vertical axis is the sensor display concentration (ppb). . As shown in FIG. 16, during the period of injecting ozone with a concentration of 400 ppb, the measurement result of the second gas sensing device 40 has no special fluctuations. This is because ozone is completely absorbed and decomposed by the filter module 13. It can be seen from the result of FIG. 16 that the detection result of the second gas sensing device 40 is not affected by the passing ozone. Therefore, FIG. 16 shows that the filter module 13 has an excellent ozone absorption effect.

FIG. 17 is a graph of the gas sensing system 50 according to the third embodiment of the present invention, and the measured current changes with time. In order to confirm the sensitivity of the gas sensing system 50 obtained in the present invention, a zero-level air generator and a dilution gas generator are first used to generate gas with different ozone concentration values. The gas containing ozone is passed into the gas sensing system 50 to obtain the corresponding current value. At the same time, the gas is analyzed with an ozone gas analyzer to determine the ozone concentration value again. Please refer to FIG. 17 for the result. FIG. 17 is a graph of the measured current with time according to the gas sensing system 50 of the second embodiment of the present invention. As shown in FIG. 17, the vertical axis on the left is the current value (μA) measured by the gas sensing system 50. The vertical axis on the right is the ozone concentration value (ppb) measured by an ozone gas analyzer (Ecotech serinus 10). The horizontal axis is time (seconds). The current value measured by the gas sensing system 50 corresponds to the ozone concentration value measured by the ozone gas analyzer. The measured current value (solid line) is close to the actual ozone concentration, and the sensitivity of the gas sensing system can reach 0 to 100ppb. From the ozone concentration measurement result in FIG. 17, it can be seen that although the structure of the gas sensing system of the present invention is not complicated, it can still measure the ppb concentration of ozone and has the ability to detect the ppb concentration.

Please refer to FIG. 18, which is a graph of the concentration of nitrogen dioxide measured by the gas sensing system 50 according to the third embodiment of the present invention. As shown in FIG. 18, the vertical axis is the concentration of nitrogen dioxide measured by the gas sensing system 50 of the present invention, and the horizontal axis is the concentration of nitrogen dioxide measured by a commercial gas sensor. The result is shown in Figure 18. For example, the coordinate point (180.0, 181.2) represents the nitrogen dioxide concentration measured by a commercial gas sensor of 180.0ppb; the nitrogen dioxide concentration measured by the gas sensing system 50 of the present invention is 181.2ppb. The measurement curve can make the regression curve relationship y=0.9658x+2.7175, and the slope of 0.9658 is very close to slope 1 (representing X=Y). It can be seen that the nitrogen dioxide detection effect of the gas sensing system 50 of the present invention is comparable to that of commercial use. The degree of the gas sensor is similar, so the present invention has sufficient reliability to meet the requirements of commercialization.

In summary, the gas sensing device and the gas sensing system of the present invention adjust the local flow field around the cover by adjusting the local flow field around the cover by having the cover with a second opening with a diameter smaller than that of the first opening and a slope surface structure. The amount of gas entering the gas sensing device through the first opening and the second opening. In this way, as the amount of gas entering the gas sensing device increases, the sensitivity and accuracy of the gas sensing device of the present invention for detecting gas concentration can also be improved. Furthermore, the gas sensing device and the gas sensing system are provided by a nano-structured working electrode containing a ternary composite metal or a working electrode containing a single metal particle and a filter module containing a nano-structured metal oxide. High sensitivity and accuracy can achieve low concentration detection limit. In addition, the gas sensing device and the gas sensing system can be used for long-term environmental monitoring.

Although the present invention is disclosed in the foregoing embodiments, it is not intended to limit the present invention. All changes and modifications made without departing from the spirit and scope of the present invention fall within the scope of patent protection of the present invention. For the scope of protection defined by the present invention, please refer to the attached patent scope.

10: Gas sensing device 11: Lid 12: Gas sensing module 13: Filter module 14-1~14-4: Conductive structure 15: shell 16: channel 20: Carrier 30: The first gas sensing device 40: The second gas sensing device 50: Gas sensing system 60: Gas sensing device 61: Lid 62: Inner container upper seat 63: Lower inner container 64: Gas sensing module 65: shell 66: filter module 110: top surface 111: gas channel 112: Bottom 113: Slope 114: Wall 120: Electrochemical sensing electrode 121: Electrolyte tank 122: first spacer 122-1: First electrolyte moisture absorption film 122-2: The first waterproof membrane 123: second spacer 123-1: Second electrolyte moisture absorption membrane 123-2: Second waterproof membrane 123-3: The fifth electrolyte moisture absorption membrane 124: Third electrolyte moisture absorption membrane 125: fourth electrolyte moisture absorption membrane 126: Embolism 127: Electrolyte 130: fixed structure 131: first electrode line 132: second electrode line 133: third electrode line 134: Fourth electrode wire 135: selective filter material 150: accommodation space 620: upper slot 621: Separation layer 622: Bottom Slot 623: Notch 624: Connecting port 625: First card firmware 626: Support Block 630: Lower seat upper slot 631: Second card firmware 632: raised structure 633: Seal hole 634: Seal 650: housing space 651: Conductive hole 652: mouth 1101: first opening 1102: second opening 1103: third opening 1200: working electrode 1200A: Hydrophobic polymer layer 1201: first auxiliary electrode 1201A: Hydrophobic polymer layer 1201B: second through hole 1202: Reference electrode 1202A: Hydrophobic polymer layer 1203: second auxiliary electrode 1203A: Hydrophobic polymer layer 1210: opening 1221: first through hole 1231: third through hole 1222: first through hole moisture absorption film 1232: Third through hole moisture absorption film 12011: Second through-hole moisture absorption film

FIG. 1A is a cross-sectional view of the gas sensing device according to the first embodiment of the present invention. FIG. 1B is a partially enlarged view of the gas sensing device according to the first embodiment of the present invention. Fig. 2 is a perspective view of the gas sensing device according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view of the gas sensing device according to the second embodiment of the present invention. FIG. 4 is an exploded view of the gas sensing device according to the second embodiment of the present invention. FIG. 5 is a perspective view of the gas sensing device according to the second embodiment of the present invention. FIG. 6 is a schematic diagram of the cover according to the second embodiment of the present invention. FIG. 7 is a schematic diagram of the filter module according to the second embodiment of the present invention. FIG. 8 is a cross-sectional view of the gas sensing module according to the second embodiment of the present invention. FIG. 9 is a schematic diagram illustrating the explosion of the gas sensing module stack according to the second embodiment of the present invention. Fig. 10 is a schematic diagram of the upper seat of the inner container according to the second embodiment of the present invention. Fig. 11 is a schematic diagram of the lower seat of the inner container according to the second embodiment of the present invention. Fig. 12 is a schematic diagram of a housing drawn according to a second embodiment of the present invention. 13A and 13B are flow field distribution diagrams according to the first embodiment and/or the second embodiment of the present invention and the comparative example. Figure 14 is an SEM image of the combination of metal oxide and hydrophobic polymer to form a selective filter material. Fig. 15 is a schematic diagram of a gas sensing system according to a third embodiment of the present invention. Fig. 16 is a concentration detection diagram of the gas sensor device including the filter module of the present invention. Fig. 17 is a graph showing the change of measured current with time according to the gas sensing system of the third embodiment of the present invention. FIG. 18 is a graph of the concentration of nitrogen dioxide measured by the gas sensing system according to the third embodiment of the present invention.

10: Gas sensing device

11: Lid

12: Gas sensing module

13: Filter module

14-1~14-4: Conductive structure

15: shell

16: channel

110: top surface

111: gas channel

112: Bottom

113: Slope

114: Wall

120: Electrochemical sensing electrode

121: Electrolyte tank

122: first spacer

123: second spacer

124: Third electrolyte moisture absorption membrane

125: fourth electrolyte moisture absorption membrane

127: Electrolyte

130: fixed structure

135: selective filter material

150: accommodation space

1100: Channel

1101: first opening

1102: second opening

1103: third opening

1200: working electrode

1201: first auxiliary electrode

1202: Reference electrode

1203: second auxiliary electrode

Claims (12)

A gas sensing device includes: a housing with an accommodating space; a cover provided on the housing, the cover having a top surface, a bottom surface and a gas channel, the bottom surface facing the accommodating Space, the gas channel communicates with the accommodating space, the gas channel has a first opening and a second opening, the first opening is located on the top surface, the second opening is located on the bottom surface, the area of the first opening Larger than the area of the second opening; and a gas sensing module disposed in the accommodating space; wherein the gas sensing module includes a working electrode, a first auxiliary electrode, a reference electrode, and a second auxiliary electrode Electrode, and an electrolyte bath, the first auxiliary electrode is located between the working electrode and the reference electrode, the reference electrode is located between the first auxiliary electrode and the second auxiliary electrode, and the second auxiliary electrode is located on the reference Between the electrode and the electrolyte tank, the working electrode includes a porous material and a nanowire structure carried on the porous material, and the nanowire structure is a ternary composite metal. The gas sensing device according to claim 1, further comprising a filter module, the filter module comprising a fixed structure and a selective filter material, the fixed structure is arranged on the cover and located in the containing space, the The selective filter material is disposed in the fixed structure, and the selective filter material shields the second opening. The selective filter material includes a metal oxide, and the metal oxide has a one-dimensional nanostructure. The gas sensing device according to claim 2, wherein the one-dimensional nanostructure is a β or γ crystal phase one-dimensional nanostructure. The gas sensing device according to claim 3, wherein the metal oxide comprises manganese dioxide, manganese trioxide, trimanganese tetraoxide or manganese oxyhydroxide (MnOOH). The gas sensing device according to claim 1, wherein the ternary composite metal is selected from the group consisting of any three metals consisting of platinum, palladium, cobalt, silver, tin, copper, nickel, gold, and ruthenium . The gas sensing device according to claim 5, wherein the ternary composite metal includes platinum cobalt silver (PtCoAg), platinum tin silver (PtSnAg), and platinum palladium nickel (PtPdNi). A gas sensing device includes: a housing with an accommodating space; a cover provided on the housing, the cover having a top surface, a bottom surface and a gas channel, the bottom surface facing the accommodating Space, the gas channel communicates with the accommodating space, the gas channel has a first opening and a second opening, the first opening is located on the top surface, the second opening is located on the bottom surface, the area of the first opening Larger than the area of the second opening; and a gas sensing module disposed in the accommodating space; wherein the gas sensing module includes a working electrode, a first auxiliary electrode, a reference electrode, and a second auxiliary electrode Electrode, and an electrolyte bath, the first auxiliary electrode is located between the working electrode and the reference electrode, the reference electrode is located between the first auxiliary electrode and the second auxiliary electrode, and the second auxiliary electrode is located on the reference Between the electrode and the electrolyte tank, the working electrode includes a porous material and a plurality of monoatomic metal particles carried on the porous material. The metal particles are composed of platinum, palladium, cobalt, silver, tin, copper, and nickel. It is composed of one of, gold and ruthenium. A gas sensing device includes: a housing with an accommodating space; a cover provided on the housing, the cover having a top surface, a bottom surface and a gas channel, the bottom surface facing the accommodating Space, the gas channel communicates with the accommodating space, and the gas channel has A first opening and a second opening, the first opening is located on the top surface, the second opening is located on the bottom surface, the area of the first opening is larger than the area of the second opening; and a gas sensing module is provided In the containing space; wherein the gas sensing module includes a working electrode, a first auxiliary electrode, a reference electrode, a second auxiliary electrode, and an electrolyte tank, the first auxiliary electrode is located at the working electrode Between the reference electrode and the reference electrode, the reference electrode is located between the first auxiliary electrode and the second auxiliary electrode, the second auxiliary electrode is located between the reference electrode and the electrolyte tank, and the working electrode includes a porous material And a plurality of first metal particles and a plurality of second metal particles carried on the porous material, the first metal particles are made of one of platinum, palladium, cobalt, silver, tin, copper, nickel, gold, and ruthenium The second metal particles are composed of a single atom of platinum, palladium, cobalt, silver, tin, copper, nickel, gold, and ruthenium, and the second metal particles and the first The metal particles are composed of different metals. A gas sensing system includes: a carrier; a first gas sensing device arranged on the carrier, and the first gas sensing device has the requirements of any one of claims 1, 5, 7-8 The structure of the gas sensing device; and a second gas sensing device arranged on the carrier, the second gas sensing device having the gas sensing contained in any one of claims 1, 5, 7-8 The structure of the device, the second gas sensing device further includes a filter module, the filter module includes a fixed structure and a selective filter material, the fixed structure is arranged on the cover and located in the containing space, the selection The sexual filter material is arranged in the fixing structure, and the selective filter material shields the second opening. The gas sensing system according to claim 9, wherein the selective filter material comprises a metal oxide, and the metal oxide has a one-dimensional nanostructure. The gas sensing system according to claim 10, wherein the one-dimensional nanostructure is a β or γ crystal phase one-dimensional nanostructure. The gas sensing system according to claim 10, wherein the metal oxide comprises manganese dioxide, manganese trioxide, trimanganese tetraoxide or manganese oxyhydroxide (MnOOH).

Images