JP6740478B2 - Gas detection electrode and gas sensor - Google Patents
Gas detection electrode and gas sensor Download PDFInfo
- Publication number
- JP6740478B2 JP6740478B2 JP2019528309A JP2019528309A JP6740478B2 JP 6740478 B2 JP6740478 B2 JP 6740478B2 JP 2019528309 A JP2019528309 A JP 2019528309A JP 2019528309 A JP2019528309 A JP 2019528309A JP 6740478 B2 JP6740478 B2 JP 6740478B2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- electrode
- ionic liquid
- complex
- gas detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000001514 detection method Methods 0.000 title claims description 57
- 239000002608 ionic liquid Substances 0.000 claims description 53
- 230000027455 binding Effects 0.000 claims description 24
- 150000004696 coordination complex Chemical class 0.000 claims description 24
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 16
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 150000004706 metal oxides Chemical group 0.000 claims description 11
- 229910044991 metal oxide Inorganic materials 0.000 claims description 9
- 229910017108 Fe—Fe Inorganic materials 0.000 claims description 6
- 239000010936 titanium Substances 0.000 claims description 6
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 3
- RAXXELZNTBOGNW-UHFFFAOYSA-O Imidazolium Chemical compound C1=C[NH+]=CN1 RAXXELZNTBOGNW-UHFFFAOYSA-O 0.000 claims description 3
- RWRDLPDLKQPQOW-UHFFFAOYSA-O Pyrrolidinium ion Chemical compound C1CC[NH2+]C1 RWRDLPDLKQPQOW-UHFFFAOYSA-O 0.000 claims description 3
- 229910003437 indium oxide Inorganic materials 0.000 claims description 3
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 claims description 3
- 229910000476 molybdenum oxide Inorganic materials 0.000 claims description 3
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 claims description 3
- 239000003960 organic solvent Substances 0.000 claims description 3
- PQQKPALAQIIWST-UHFFFAOYSA-N oxomolybdenum Chemical compound [Mo]=O PQQKPALAQIIWST-UHFFFAOYSA-N 0.000 claims description 3
- XYFCBTPGUUZFHI-UHFFFAOYSA-O phosphonium Chemical compound [PH4+] XYFCBTPGUUZFHI-UHFFFAOYSA-O 0.000 claims description 3
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims description 3
- 229910001887 tin oxide Inorganic materials 0.000 claims description 3
- 229910001930 tungsten oxide Inorganic materials 0.000 claims description 3
- 239000007789 gas Substances 0.000 description 111
- 239000010931 gold Substances 0.000 description 15
- 239000007864 aqueous solution Substances 0.000 description 13
- 238000002484 cyclic voltammetry Methods 0.000 description 11
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 10
- 229910052737 gold Inorganic materials 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 230000035945 sensitivity Effects 0.000 description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 239000007822 coupling agent Substances 0.000 description 7
- 229910052717 sulfur Inorganic materials 0.000 description 7
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 6
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 6
- 125000004434 sulfur atom Chemical group 0.000 description 6
- 239000011148 porous material Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- -1 succinimidyl ester Chemical class 0.000 description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 125000003277 amino group Chemical group 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 230000003100 immobilizing effect Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- ZHNUHDYFZUAESO-UHFFFAOYSA-N Formamide Chemical compound NC=O ZHNUHDYFZUAESO-UHFFFAOYSA-N 0.000 description 2
- 239000006087 Silane Coupling Agent Substances 0.000 description 2
- 229910021607 Silver chloride Inorganic materials 0.000 description 2
- 125000004429 atom Chemical group 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 239000003446 ligand Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000012466 permeate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 230000009870 specific binding Effects 0.000 description 2
- 238000004528 spin coating Methods 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- BPSIOYPQMFLKFR-UHFFFAOYSA-N trimethoxy-[3-(oxiran-2-ylmethoxy)propyl]silane Chemical compound CO[Si](OC)(OC)CCCOCC1CO1 BPSIOYPQMFLKFR-UHFFFAOYSA-N 0.000 description 2
- CHEANNSDVJOIBS-MHZLTWQESA-N (3s)-3-cyclopropyl-3-[3-[[3-(5,5-dimethylcyclopenten-1-yl)-4-(2-fluoro-5-methoxyphenyl)phenyl]methoxy]phenyl]propanoic acid Chemical compound COC1=CC=C(F)C(C=2C(=CC(COC=3C=C(C=CC=3)[C@@H](CC(O)=O)C3CC3)=CC=2)C=2C(CCC=2)(C)C)=C1 CHEANNSDVJOIBS-MHZLTWQESA-N 0.000 description 1
- PXELHGDYRQLRQO-UHFFFAOYSA-N 1-butyl-1-methylpyrrolidin-1-ium Chemical compound CCCC[N+]1(C)CCCC1 PXELHGDYRQLRQO-UHFFFAOYSA-N 0.000 description 1
- 241000252506 Characiformes Species 0.000 description 1
- BWGNESOTFCXPMA-UHFFFAOYSA-N Dihydrogen disulfide Chemical compound SS BWGNESOTFCXPMA-UHFFFAOYSA-N 0.000 description 1
- SNRUBQQJIBEYMU-UHFFFAOYSA-N Dodecane Natural products CCCCCCCCCCCC SNRUBQQJIBEYMU-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000007983 Tris buffer Substances 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 125000000058 cyclopentadienyl group Chemical group C1(=CC=CC1)* 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- DHCWLIOIJZJFJE-UHFFFAOYSA-L dichlororuthenium Chemical compound Cl[Ru]Cl DHCWLIOIJZJFJE-UHFFFAOYSA-L 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical group [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 125000002228 disulfide group Chemical group 0.000 description 1
- 238000007606 doctor blade method Methods 0.000 description 1
- 125000003438 dodecyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 238000002848 electrochemical method Methods 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- KQNPFQTWMSNSAP-UHFFFAOYSA-N isobutyric acid Chemical compound CC(C)C(O)=O KQNPFQTWMSNSAP-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920000052 poly(p-xylylene) Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000011164 primary particle Substances 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 238000007142 ring opening reaction Methods 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 239000003115 supporting electrolyte Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- ITMCEJHCFYSIIV-UHFFFAOYSA-M triflate Chemical compound [O-]S(=O)(=O)C(F)(F)F ITMCEJHCFYSIIV-UHFFFAOYSA-M 0.000 description 1
- JFZKOODUSFUFIZ-UHFFFAOYSA-N trifluoro phosphate Chemical compound FOP(=O)(OF)OF JFZKOODUSFUFIZ-UHFFFAOYSA-N 0.000 description 1
- 238000002525 ultrasonication Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/416—Systems
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Physics & Mathematics (AREA)
- Electrochemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Molecular Biology (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Description
本発明は、ガス検出用電極及びガスセンサに関する。 The present invention relates to a gas detection electrode and a gas sensor.
ガスセンサとしては、特許文献１に開示されているように、ガス吸収体としてイオン液体を使用し、イオン液体が陽極と陰極とを覆い、両極間のインピーダンスの値から検出対象のガスの検出を行うものが知られている。このガスセンサでは、検出対象となるガスの種類に応じてそのガスを吸収可能なイオン液体を適宜選定する。しかし、検出対象となるガスを選択的に吸収するイオン液体を選定するのは容易ではなかった。一方、非特許文献１には、選択的にＮＯを捕捉する能力を有するＣｏ錯体を、嵩高いホスホニウムタイプのイオン液体で改質されたＡｕ電極上に固定化する技術が開示されている。イオン液体は、分子の末端に硫黄原子を有し、その硫黄原子がＡｕ電極と結合している。水中のＮＯ濃度は、こうした電極を用いることにより電気化学的に評価することができる。非特許文献１の技術をガスセンサに適用すれば、特許文献１のガスセンサに比べて、検出対象のガスをより選択的に検出できると考えられる。 As the gas sensor, as disclosed in Patent Document 1, an ionic liquid is used as a gas absorber, the ionic liquid covers the anode and the cathode, and the gas to be detected is detected from the impedance value between both electrodes. Things are known. In this gas sensor, an ionic liquid capable of absorbing the gas is appropriately selected according to the type of gas to be detected. However, it has not been easy to select an ionic liquid that selectively absorbs the gas to be detected. On the other hand, Non-Patent Document 1 discloses a technique of immobilizing a Co complex having the ability to selectively capture NO on an Au electrode modified with a bulky phosphonium-type ionic liquid. The ionic liquid has a sulfur atom at the end of the molecule, and the sulfur atom is bonded to the Au electrode. The NO concentration in water can be evaluated electrochemically by using such an electrode. When the technique of Non-Patent Document 1 is applied to the gas sensor, it is considered that the gas to be detected can be detected more selectively than the gas sensor of Patent Document 1.
しかしながら、非特許文献１の技術では、検出対象のガスを選択的に検出できるものの、ガスセンサの電極に繰り返し電圧を印加したりガスセンサを高温で使用したりすると、イオン液体中の硫黄原子とＡｕ電極との結合が外れてしまうことがあった。そのため、耐久性に優れたガス検出用電極の開発が望まれていた。 However, in the technique of Non-Patent Document 1, although the gas to be detected can be selectively detected, when a voltage is repeatedly applied to the electrode of the gas sensor or the gas sensor is used at high temperature, the sulfur atom in the ionic liquid and the Au electrode The bond with was sometimes broken. Therefore, development of a gas detection electrode having excellent durability has been desired.
本発明はこのような課題を解決するためになされたものであり、耐久性に優れたガス検出用電極を提供することを主目的とする。 The present invention has been made to solve such a problem, and a main object thereof is to provide a gas detection electrode having excellent durability.
本発明のガス検出用電極は、
導電性を有する構造体と、
第１結合部位で前記構造体に共有結合するリンカー部と、
前記リンカー部のうち前記第１結合部位とは異なる第２結合部位で前記リンカー部と共有結合するイオン液体と、
特定のガスを選択的に捕捉する性質を持ち、前記イオン液体を介して固定化された金属錯体と、
を備えたものである。The gas detection electrode of the present invention,
A structure having conductivity,
A linker portion covalently bonded to the structure at the first binding site,
An ionic liquid that is covalently bonded to the linker part at a second binding site different from the first binding site in the linker part;
Having a property of selectively capturing a specific gas, a metal complex immobilized via the ionic liquid,
It is equipped with.
本発明のガス検出用電極は、構造体にリンカー部が共有結合し、そのリンカー部にイオン液体が共有結合し、そのイオン液体を介して金属錯体が固定化されている。このガス検出用電極を作用極とするサイクリックボルタンメトリにおいて、金属錯体が選択的に捕捉することのできる特定のガスの濃度を変化させると、その濃度に応じて発生する電子の量が変化する。そのため、このガス検出用電極は、その特定のガス（検出対象のガス）を検出する電極として利用することができる。また、構造体とイオン液体は、リンカー部にそれぞれ第１結合部位及び第２結合部位で共有結合されている。こうした共有結合は、非特許文献１のＡｕと硫黄原子との結合に比べて結合力が強く、電圧や高温に対する耐久性が高い。したがって、本発明によれば、耐久性に優れたガス検出用電極を提供することができる。 In the gas detection electrode of the present invention, a linker part is covalently bonded to the structure, an ionic liquid is covalently bonded to the linker part, and a metal complex is immobilized via the ionic liquid. In cyclic voltammetry using this gas detection electrode as the working electrode, when the concentration of a specific gas that can be selectively captured by the metal complex is changed, the amount of electrons generated changes according to that concentration. To do. Therefore, the gas detection electrode can be used as an electrode for detecting the specific gas (gas to be detected). Further, the structure and the ionic liquid are covalently bonded to the linker portion at the first binding site and the second binding site, respectively. Such a covalent bond has a stronger bonding force than the bond between Au and a sulfur atom in Non-Patent Document 1 and has high durability against voltage and high temperature. Therefore, according to the present invention, it is possible to provide a gas detection electrode having excellent durability.
本発明のガス検出用電極において、前記構造体は、多孔体であることが好ましい。こうすれば、構造体が緻密体の場合に比べて、単位体積当たりの表面積が大きくなる。そのため、構造体に結合されるリンカー部、イオン液体及びそのイオン液体に固定化される金属錯体の量も構造体が緻密体の場合に比べて多くなり、検出可能なガス濃度範囲が広くなる。 In the gas detection electrode of the present invention, the structure is preferably a porous body. In this case, the surface area per unit volume is larger than that in the case where the structure is a dense body. Therefore, the amounts of the linker portion bound to the structure, the ionic liquid, and the metal complex fixed to the ionic liquid are larger than those in the case where the structure is a dense body, and the detectable gas concentration range is widened.
本発明のガス検出用電極において、前記構造体は、導電性を有する金属酸化物の構造体であることが好ましい。金属酸化物は電圧や高温に対する耐久性が高いため、本発明のガス検出用電極の構造体として用いるのに適している。こうした金属酸化物は、特に限定するものではないが、例えば、酸化チタン、酸化スズ、酸化インジウム、酸化タングステン及び酸化モリブデンからなる群より選ばれた１種としてもよい。 In the gas detection electrode of the present invention, it is preferable that the structure is a conductive metal oxide structure. Since metal oxide has high durability against voltage and high temperature, it is suitable for use as a structure of the gas detection electrode of the present invention. The metal oxide is not particularly limited, but may be, for example, one selected from the group consisting of titanium oxide, tin oxide, indium oxide, tungsten oxide and molybdenum oxide.
本発明のガス検出用電極において、前記イオン液体と前記金属錯体との組合せは、ホスホニウムタイプのイオン液体と４配位のＣｏ錯体との組合せであるか、アンモニウムタイプのイオン液体と６配位のＦｅ−Ｆｅ錯体との組合せであるか、ピロリジニウムタイプのイオン液体と４配位のＴｉ錯体との組合せであるか、又は、イミダゾリウムタイプのイオン液体と６配位のＲｕ錯体との組合せとしてもよい。４配位のＣｏ錯体は選択的にＮＯガスを捕捉する。６配位のＦｅ−Ｆｅ錯体は選択的にＯ2ガスを捕捉する。４配位のＴｉ錯体は選択的にＮ2ガスを捕捉する。６配位のＲｕ錯体は選択的にＮＨ3ガスを捕捉する。In the gas detection electrode of the present invention, the combination of the ionic liquid and the metal complex is a combination of a phosphonium type ionic liquid and a tetracoordinated Co complex, or an ammonium type ionic liquid and a hexacoordinated ligand. A combination of an Fe-Fe complex, a pyrrolidinium type ionic liquid and a tetracoordinate Ti complex, or a combination of an imidazolium type ionic liquid and a hexacoordinate Ru complex. May be The tetracoordinated Co complex selectively traps NO gas. Fe-Fe complex hexacoordinate captures selectively O 2 gas. The tetracoordinated Ti complex selectively traps N 2 gas. The hexacoordinated Ru complex selectively traps NH 3 gas.
本発明のガスセンサは、上述したガス検出用電極と、前記ガス検出用電極と対をなすカウンタ電極と、前記ガス検出用電極と前記カウンタ電極との隙間に充填され、検出対象ガスを含有可能な媒体と、を備えたものである。本発明のガスセンサは、上述したガス検出用電極を使用しているため、検出対象のガスを選択的にかつ広濃度範囲で検出できる。 The gas sensor of the present invention is filled with the gas detection electrode described above, a counter electrode forming a pair with the gas detection electrode, a gap between the gas detection electrode and the counter electrode, and can contain a gas to be detected. And a medium. Since the gas sensor of the present invention uses the above-mentioned gas detection electrode, the gas to be detected can be detected selectively and in a wide concentration range.
本発明のガスセンサにおいて、前記媒体は、イオン液体、水、有機系溶媒又は大気としてもよい。 In the gas sensor of the present invention, the medium may be an ionic liquid, water, an organic solvent or the atmosphere.
本発明の好適な実施形態を、図面を参照しながら以下に説明する。図１は本実施形態のガスセンサ１０の概略構成を示す断面図、図２は図１の１点鎖線の四角形内を拡大した拡大断面図、図３は構造体２２とカップリング剤２３とイオン液体２６との模式的な反応式を示す説明図である。 Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of a gas sensor 10 of the present embodiment, FIG. 2 is an enlarged cross-sectional view enlarging the inside of the one-dot chain line rectangle of FIG. It is explanatory drawing which shows the typical reaction formula with 26.
本実施形態のガスセンサ１０は、図１に示すように、本体カバー１２の内部に、ガス検出用電極２０とカウンタ電極３０と媒体４０と参照電極５０を備えたものである。 As shown in FIG. 1, the gas sensor 10 of the present embodiment is provided with a gas detection electrode 20, a counter electrode 30, a medium 40, and a reference electrode 50 inside a main body cover 12.
本体カバー１２は、内部に空間を有する立体形状の部材である。本体カバー１２の上面には、複数の開口部１２ａが設けられている。開口部１２ａは、ガス透過膜（液体は透過しないがガスは透過する膜）で被覆されていてもよいし、ガス透過膜とメッシュ部材の両方で被覆されていてもよい。ガス透過膜としては、例えばパリレン膜が挙げられる。 The body cover 12 is a three-dimensional member having a space inside. A plurality of openings 12 a are provided on the upper surface of the body cover 12. The opening 12a may be covered with a gas permeable film (a film that does not allow liquid to permeate but allows gas to permeate), or may be covered with both a gas permeable film and a mesh member. Examples of the gas permeable film include a parylene film.
ガス検出用電極２０は、本体カバー１２の上面裏側に配置され、リード線により外部端子２１に接続されている。ガス検出用電極２０は、図２に示すように、構造体２２と、リンカー部２４と、イオン液体２６と、金属錯体２８とを有している。 The gas detection electrode 20 is arranged on the back side of the upper surface of the body cover 12, and is connected to the external terminal 21 by a lead wire. As shown in FIG. 2, the gas detection electrode 20 has a structure 22, a linker portion 24, an ionic liquid 26, and a metal complex 28.
構造体２２は、導電性材料で形成された多孔体であり、表面に多数の孔２２ａを有している。構造体２２は、孔２２ａを有しない場合に比べて単位体積当たりの表面積が大きい。構造体２２は、三次元網目構造からなる多孔体でもよいし、ハニカム構造からなる多孔体でもよい。構造体２２の気孔率は、特に限定するものではないが、例えば１０％以上であることが好ましく、３０％以上７０％以下であることがより好ましい。孔２２ａは、開気孔であってもよいし閉気孔であってもよい。構造体２２を構成する材料としては、特に限定するものではないが、導電性を有する酸化物が好ましく、導電性を有する金属酸化物がより好ましい。こうした金属酸化物としては、特に限定するものではないが、例えば、酸化チタン、酸化スズ、酸化インジウム、酸化タングステン及び酸化モリブデンからなる群より選ばれた１種としてもよい。孔２２ａのサイズは、孔２２ａの表面にリンカー部２４及びイオン液体２６を介して金属錯体２８が固定化されるのを許容するサイズであることが好ましく、０．０１μｍ以上１ｍｍ以下とするのが好ましく、０．０５μｍ以上１０μｍ以下とするのがより好ましい。 The structure 22 is a porous body made of a conductive material and has a large number of holes 22a on its surface. The structure 22 has a larger surface area per unit volume than when the structure 22 does not have the holes 22a. The structure 22 may be a porous body having a three-dimensional mesh structure or a honeycomb structure. The porosity of the structure 22 is not particularly limited, but is preferably 10% or more, and more preferably 30% or more and 70% or less. The holes 22a may be open pores or closed pores. The material forming the structure 22 is not particularly limited, but an oxide having conductivity is preferable, and a metal oxide having conductivity is more preferable. The metal oxide is not particularly limited, but may be, for example, one selected from the group consisting of titanium oxide, tin oxide, indium oxide, tungsten oxide and molybdenum oxide. The size of the hole 22a is preferably a size that allows the metal complex 28 to be immobilized on the surface of the hole 22a via the linker portion 24 and the ionic liquid 26, and is preferably 0.01 μm or more and 1 mm or less. The thickness is preferably 0.05 μm or more and 10 μm or less.
リンカー部２４は、図２に示すように、構造体２２の表面に第１結合部位Ｂ１で共有結合され、イオン液体２６に第２結合部位Ｂ２で共有結合されている。リンカー部２４は、第１結合部位Ｂ１と第２結合部位Ｂ２との間に中間部２４ａを備えている。中間部２４ａは、Ｃ，Ｏ，Ｓ及びＮの少なくとも１つ以上の原子を含む。中間部２４ａは、直鎖部分を有していてもよく、さらに直鎖部分に結合する形で側鎖を有していてもよく、その場合、直鎖部分を構成する原子の数は２０以下が好ましい。第１結合部位Ｂ１の具体的な結合形態は、特に限定されるものではないが、構造体２２が金属酸化物の場合には構造体２２の表面にＯＨ基が現れているため、例えば、エーテル結合やエステル結合、シロキサン結合などが挙げられる。エーテル結合は、図３において、リンカー部２４の元となる二価性のカップリング剤２３のＺがＯＨ基の場合に、そのＯＨ基と構造体２２の表面のＯＨ基との脱水縮合によって形成される。エステル結合は、カップリング剤２３のＺが酸ハライド、カルボン酸、エステル又はスクシニミジルエステルの場合に、そのＺと構造体２２の表面のＯＨ基との縮合によって形成される。シロキサン結合は、カップリング剤２３のＺがアルコキシシランの場合に、そのアルコキシシランと構造体２２の表面のＯＨ基との縮合によって形成される。第２結合部位Ｂ２の具体的な結合形態も、特に限定されるものではないが、図３において、二価性のカップリング剤２３の官能基Ｘとイオン液体２６に含まれる官能基Ｙとによって決定される。カップリング剤２３をＲ1−Ｘ、イオン液体２６をＲ2−Ｙ、両者が結合した構造をＲ1−Ｂ２−Ｒ2 と表したときの代表的な組合せ例を表１に示す。As shown in FIG. 2, the linker part 24 is covalently bonded to the surface of the structure 22 at the first binding site B1 and is covalently bonded to the ionic liquid 26 at the second binding site B2. The linker portion 24 includes an intermediate portion 24a between the first binding site B1 and the second binding site B2. The intermediate portion 24a includes at least one atom of C, O, S and N. The intermediate portion 24a may have a straight chain portion and may further have a side chain so as to be bonded to the straight chain portion. In that case, the number of atoms constituting the straight chain portion is 20 or less. Is preferred. The specific binding form of the first binding site B1 is not particularly limited, but when the structure 22 is a metal oxide, since OH groups appear on the surface of the structure 22, for example, ether. A bond, an ester bond, a siloxane bond and the like can be mentioned. In FIG. 3, the ether bond is formed by dehydration condensation between the OH group and the OH group on the surface of the structure 22 when Z of the divalent coupling agent 23 that is the source of the linker portion 24 is an OH group in FIG. To be done. The ester bond is formed by condensation of Z with the OH group on the surface of the structure 22 when Z of the coupling agent 23 is an acid halide, carboxylic acid, ester or succinimidyl ester. The siloxane bond is formed by condensation of the alkoxysilane and the OH group on the surface of the structure 22 when Z of the coupling agent 23 is an alkoxysilane. The specific binding form of the second binding site B2 is also not particularly limited, but in FIG. 3, depending on the functional group X of the divalent coupling agent 23 and the functional group Y contained in the ionic liquid 26. It is determined. Table 1 shows a typical combination example in which the coupling agent 23 is represented by R 1 -X, the ionic liquid 26 is represented by R 2 -Y, and the structure in which both are bonded is represented by R 1 -B 2 -R 2 .
イオン液体２６は、リンカー部２４のうち第１結合部位Ｂ１とは異なる第２結合部位Ｂ２でリンカー部２４と共有結合されている。イオン液体２６としては、金属錯体２８を固定化可能な材料を用いる。 The ionic liquid 26 is covalently bonded to the linker portion 24 at a second binding portion B2 of the linker portion 24 that is different from the first binding portion B1. As the ionic liquid 26, a material capable of immobilizing the metal complex 28 is used.
金属錯体２８は、検出対象のガスを選択的に捕捉する性質を持ち、イオン液体２６の間に固定化されている。例えば、金属錯体２８が４配位のＣｏ錯体の場合にはホスホニウムタイプのイオン液体を用いることが好ましい。こうしたＣｏ錯体は選択的にＮＯガスを捕捉する。一例として、式（１）のイオン液体と式（２）のＣｏ錯体との組合せが挙げられる。 The metal complex 28 has a property of selectively capturing the gas to be detected, and is fixed between the ionic liquids 26. For example, when the metal complex 28 is a tetracoordinated Co complex, it is preferable to use a phosphonium type ionic liquid. Such a Co complex selectively captures NO gas. An example is a combination of an ionic liquid of formula (1) and a Co complex of formula (2).
金属錯体２８が６配位のＦｅ−Ｆｅ錯体（核に２つのＦｅを有する錯体）の場合にはアンモニウムタイプのイオン液体を用いることが好ましい。こうしたＦｅ−Ｆｅ錯体は選択的にＯ2ガスを捕捉する。一例として、式（３）のイオン液体と式（４）のＦｅ−Ｆｅ錯体との組合せが挙げられる。When the metal complex 28 is a 6-coordinate Fe-Fe complex (complex having two Fe in the nucleus), it is preferable to use an ammonium type ionic liquid. Such Fe-Fe complex selectively captures O 2 gas. An example is a combination of the ionic liquid of formula (3) and the Fe-Fe complex of formula (4).
金属錯体２８が４配位のＴｉ錯体の場合にはピロリジニウムタイプのイオン液体を用いることが好ましい。こうしたＴｉ錯体は選択的にＮ2ガスを捕捉する。一例として、１−ブチル−１−メチルピロリジニウム トリス（ペンタフルオロエチル）トリフルオロホスフェートとＣｐ2ＴｉＣｌ2（Ｃｐはシクロペンタジエニル基）との組合せが挙げられる。When the metal complex 28 is a tetra-coordinated Ti complex, it is preferable to use a pyrrolidinium type ionic liquid. Such Ti complex selectively traps N 2 gas. One example is a combination of 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate and Cp 2 TiCl 2 (Cp is a cyclopentadienyl group).
金属錯体２８が６配位のＲｕ錯体の場合にはイミダゾリウムタイプのイオン液体を用いることが好ましい。こうしたＲｕ錯体は選択的にＮＨ3ガスを捕捉する。一例として、１−ブチル−３−メチルイミダゾリウム ヘキサフルオロホスフェートとトリス（２，２’−ビピリジル）ルテニウム（II）クロリドとの組合せが挙げられる。When the metal complex 28 is a hexacoordinate Ru complex, it is preferable to use an imidazolium type ionic liquid. Such Ru complex selectively traps NH 3 gas. An example is the combination of 1-butyl-3-methylimidazolium hexafluorophosphate and tris(2,2'-bipyridyl)ruthenium(II) chloride.
カウンタ電極３０は、本体カバー１２の底面にガス検出用電極２０と対向する位置に配置され、リード線により外部端子３１に接続されている。カウンタ電極３０を構成する材料は、導電性を有するものであれば特に限定されないが、例えば白金、金、ニッケルが挙げられる。ガス検出用電極２０とカウンタ電極３０との間には隙間（スペース）が設けられている。 The counter electrode 30 is arranged on the bottom surface of the body cover 12 at a position facing the gas detection electrode 20, and is connected to the external terminal 31 by a lead wire. The material forming the counter electrode 30 is not particularly limited as long as it has conductivity, and examples thereof include platinum, gold, and nickel. A gap (space) is provided between the gas detection electrode 20 and the counter electrode 30.
媒体４０は、ガス検出用電極２０とカウンタ電極３０との隙間に充填されている。媒体４０は、検出対象ガスを含有可能であれば特に限定されないが、例えばイオン液体、水、有機系溶媒、大気などが挙げられる。図１には媒体４０が水の場合を例示した。 The medium 40 is filled in the gap between the gas detection electrode 20 and the counter electrode 30. The medium 40 is not particularly limited as long as it can contain the gas to be detected, and examples thereof include an ionic liquid, water, an organic solvent, and the atmosphere. FIG. 1 illustrates the case where the medium 40 is water.
参照電極５０は、媒体４０中に位置するよう配置されている。参照電極５０は、導電性を有するものであれば特に限定されないが、表面を銀／塩化銀又は銀でメッキしておくことなどが挙げられる。 The reference electrode 50 is arranged so as to be located in the medium 40. The reference electrode 50 is not particularly limited as long as it has conductivity, and examples thereof include plating the surface with silver/silver chloride or silver.
次に、ガスセンサ１０の使用例について説明する。ガスセンサ１０を使用する際には、特定のガス６０が存在する雰囲気にガスセンサ１０を配置する。すると、特定のガス６０が本体カバー１２の開口部１２ａから媒体４０に溶解し、媒体４０に溶解した特定のガス６０が金属錯体２８に捕捉される。図１の点線矢印はガス６０が捕捉される様子を模式的に示したものである。ガス６０が金属錯体２８に捕捉されると、それによって生じる電子が導電性の構造体２２へ移動する。その電子の移動に伴って２つの外部端子２１，３１の間に電流が流れるため、その電流を測定し、その電流に基づいて媒体４０に含まれる特定のガス６０の濃度を求める。 Next, a usage example of the gas sensor 10 will be described. When using the gas sensor 10, the gas sensor 10 is arranged in an atmosphere in which the specific gas 60 exists. Then, the specific gas 60 is dissolved in the medium 40 through the opening 12 a of the body cover 12, and the specific gas 60 dissolved in the medium 40 is captured by the metal complex 28. The dotted arrow in FIG. 1 schematically shows how the gas 60 is trapped. When the gas 60 is captured by the metal complex 28, the electrons generated thereby move to the conductive structure 22. Since a current flows between the two external terminals 21 and 31 as the electrons move, the current is measured and the concentration of the specific gas 60 contained in the medium 40 is obtained based on the current.
以上説明した本実施形態によれば、特定（検出対象）のガス６０を選択的に検出できる。すなわち、このガス検出用電極２０を作用極とするサイクリックボルタンメトリにおいて、金属錯体２８に選択的に捕捉される特定のガス６０の濃度を変化させると、その濃度に応じて発生する電子の量が変化する。そのため、このガス検出用電極２０は、その特定のガス６０を検出する電極として利用することができる。選択的に捕捉された特定のガス６０は、電位を正の方向に挿引することにより、離脱させることができる。これによって金属錯体２８にはガスが捕捉されていない初期状態に戻すことができ、ガスセンサ１０を再生することが可能である。 According to this embodiment described above, the specific (detection target) gas 60 can be selectively detected. That is, in the cyclic voltammetry using the gas detection electrode 20 as the working electrode, when the concentration of the specific gas 60 selectively captured by the metal complex 28 is changed, the electrons generated according to the concentration are changed. The amount changes. Therefore, the gas detection electrode 20 can be used as an electrode for detecting the specific gas 60. The selectively trapped specific gas 60 can be released by pulling the electric potential in the positive direction. Thereby, the metal complex 28 can be returned to the initial state in which the gas is not captured, and the gas sensor 10 can be regenerated.
また、構造体２２とイオン液体２６は、リンカー部２４にそれぞれ第１結合部位Ｂ１及び第２結合部位Ｂ２で共有結合されている。こうした共有結合は、非特許文献１のＡｕと硫黄原子との結合に比べて結合力が強く、電圧や高温に対する耐久性が高い。したがって、ガス検出用電極２０は、従来品に比べて耐久性に優れる。特に構造体２２は金属酸化物で構成されているため、より耐久性に優れたものが得られる。 Further, the structure 22 and the ionic liquid 26 are covalently bonded to the linker portion 24 at the first binding site B1 and the second binding site B2, respectively. Such a covalent bond has a stronger bonding force than the bond between Au and a sulfur atom in Non-Patent Document 1 and has high durability against voltage and high temperature. Therefore, the gas detection electrode 20 is more durable than the conventional product. In particular, since the structure 22 is made of a metal oxide, a structure having more excellent durability can be obtained.
更に、ガス検出用電極２０の構造体２２は、多孔体であるため、緻密体に比べて単位体積当たりの表面積が大きい。そのため、構造体２２に結合されるリンカー部２４、イオン液体２６及びそのイオン液体２６に固定化される金属錯体２８の量も緻密体の場合に比べて多くなり、検出可能なガス濃度範囲が広くなる。 Furthermore, since the structure 22 of the gas detection electrode 20 is a porous body, it has a larger surface area per unit volume than a dense body. Therefore, the amount of the linker portion 24 bonded to the structure 22, the ionic liquid 26, and the metal complex 28 fixed to the ionic liquid 26 is also larger than that of the dense body, and the detectable gas concentration range is wide. Become.
更にまた、多孔体である構造体２２の単位体積当たりの表面積を大きくすることで、検出感度をより向上させたりガスとの反応効率をより向上させたりすることができる。また、ガス検出用電極２０を小型化することができるため、ガスセンサ１０を小型化することができる。 Furthermore, by increasing the surface area per unit volume of the structure 22 which is a porous body, it is possible to further improve the detection sensitivity and the reaction efficiency with gas. Moreover, since the gas detection electrode 20 can be downsized, the gas sensor 10 can be downsized.
なお、本発明は上述した実施形態に何ら限定されることはなく、本発明の技術的範囲に属する限り種々の態様で実施し得ることはいうまでもない。 Needless to say, the present invention is not limited to the above-described embodiments and can be implemented in various modes as long as they are within the technical scope of the present invention.
例えば、上述した実施形態では、構造体２２として多孔体を用いたが、緻密体を用いてもよい。その場合、多孔体に比べて単位体積当たりの表面積が小さくなる分、検出可能なガス濃度範囲が狭くなるが、従来品に比べて耐久性は高くなる。 For example, in the above-described embodiment, the porous body is used as the structure 22, but a dense body may be used. In that case, since the surface area per unit volume is smaller than that of the porous body, the detectable gas concentration range is narrowed, but the durability is higher than that of the conventional product.
上述した実施形態では、構造体２２を導電性を有する金属酸化物で形成したが、導電性を有する材料であれば特に金属酸化物に限定されるものではない。例えば、金属多孔体（チタン多孔体、ステンレス多孔体など）でもよいし、絶縁性を有する多孔体の表面に導電性膜を被覆したものでもよい。 In the above-described embodiment, the structure 22 is formed of the conductive metal oxide, but the material is not limited to the metal oxide as long as it is a conductive material. For example, it may be a metal porous body (titanium porous body, stainless steel porous body, etc.), or may be a porous body having an insulating property coated with a conductive film.
上述した実施形態では、リンカー部２４は、第１結合部位Ｂ１と第２結合部位Ｂ２との間に中間部２４ａを備えた構造としたが、第１結合部位Ｂ１と第２結合部位Ｂ２とが直接結合した構造であってもよい。 In the above-described embodiment, the linker portion 24 has a structure including the intermediate portion 24a between the first binding site B1 and the second binding site B2, but the first binding site B1 and the second binding site B2 are The structure may be a direct bond.
上述した実施形態では、ＮＯガス等に合った金属錯体２８の具体例を例示したが、金属錯体２８を適宜選択すればその他のガス（例えばＨ2、Ｎ2Ｏ、ＣＯ2など）についても検出可能となる。その際、適切なイオン液体を選択し、このイオン液体を介して金属錯体を電極表面に固定化することで実施可能である。In the above-described embodiment, a specific example of the metal complex 28 suitable for NO gas or the like has been illustrated, but other gases (for example, H 2 , N 2 O, CO 2 etc.) can be detected if the metal complex 28 is appropriately selected. It will be possible. At that time, it can be carried out by selecting an appropriate ionic liquid and immobilizing the metal complex on the electrode surface through the ionic liquid.
上述した実施形態では、ガスセンサ１０に参照電極５０を設けたが、電極電位の測定を行わない場合には参照電極５０を省略してもよい。 Although the reference electrode 50 is provided in the gas sensor 10 in the above-described embodiment, the reference electrode 50 may be omitted when the electrode potential is not measured.
以下に、本発明の実施例について説明する。なお、以下の実施例は本発明を何ら限定するものではない。 Examples of the present invention will be described below. The following examples do not limit the present invention.
［比較例１］
１．ガス検出用電極
特開２０１４−２１０６９７号公報を参考にして平均気孔径４００μｍ、気孔率８０％の三次元網目構造を有するＳｉ−ＳｉＣ焼結体（１０ｍｍ×１０ｍｍ×５ｍｍ）を作製した。このＳｉ−ＳｉＣ焼結体に、無電解めっきによりニッケル被膜を形成（膜厚約２μｍ）した後、電解めっきによりニッケル被膜を金で覆い、金被覆多孔体電極を作製した。金の膜厚は約２００ｎｍ、金被覆多孔体電極の表面積は孔の内部の表面積を含んで約４０ｃｍ2であり、単位体積当たりの表面積は約８０ｃｍ2であった。[Comparative Example 1]
1. Gas Detection Electrode A Si—SiC sintered body (10 mm×10 mm×5 mm) having a three-dimensional network structure with an average pore diameter of 400 μm and a porosity of 80% was prepared with reference to JP-A-2014-210697. A nickel coating was formed on this Si-SiC sintered body by electroless plating (film thickness of about 2 μm), and then the nickel coating was covered with gold by electrolytic plating to produce a gold-coated porous electrode. The film thickness of gold was about 200 nm, the surface area of the gold-coated porous electrode was about 40 cm 2 including the surface area inside the pores, and the surface area per unit volume was about 80 cm 2 .
続いて、非特許文献１に記載のホスホニウムタイプのイオン液体であるビス［１２−（トリヘキシルホスホニウム）ドデシル］ジスルファン ビス（トリフルオロメタンスルホネート）（以下「ＩＬ」という）とエタノールの混合液中に、準備した金被覆多孔体電極を２週間浸漬した後、過剰のＩＬを除くため、エタノール、クロロホルムで洗浄し、金被覆多孔体電極の表面にＩＬが固定された電極（ＩＬ固定電極）を得た。 Then, in a mixed solution of bis[12-(trihexylphosphonium)dodecyl]disulfane bis(trifluoromethanesulfonate) (hereinafter referred to as “IL”), which is the phosphonium-type ionic liquid described in Non-Patent Document 1, and ethanol, After the prepared gold-coated porous body electrode was immersed for 2 weeks, it was washed with ethanol and chloroform to remove excess IL to obtain an electrode (IL fixed electrode) having IL immobilized on the surface of the gold-coated porous body electrode. ..
最後に、非特許文献１に記載のＮ２Ｓ２型配位子を持つ平面四角形Ｃｏ（III）錯体（式（２）参照、以下「Ｃｏ錯体」という）を溶解させた水溶液中に、上述のＩＬ固定電極を１週間浸漬した後、過剰のＣｏ錯体を除くため、ジメチルホルムアミド、アセトニトリル、純水で洗浄し、ＮＯ応答性のＣｏ錯体−ＩＬ固定電極（ガス検出用電極）を得た。 Finally, the above-mentioned IL immobilization is performed in an aqueous solution in which a planar quadrangular Co(III) complex having an N2S2 type ligand described in Non-Patent Document 1 (see Formula (2), hereinafter referred to as "Co complex") is dissolved. After immersing the electrode for 1 week, it was washed with dimethylformamide, acetonitrile, and pure water to remove an excess Co complex, and an NO-responsive Co complex-IL fixed electrode (gas detection electrode) was obtained.
２．ＮＯガス検出感度
（１）初期検出感度
測定用ＮＯガスは、予め純水、ＫＯＨ水溶液の順にバブリングを行い、ＮＯ2ガスや硝酸塩を除いたものを使用した。また、ＮＯ水溶液は、１０ｍＬの純水に数時間Ａｒガスをパージした後、純水とＮＯガス存在下、２０分バブリングすることでＮＯ水溶液（１．９ｍＭ）を調製した。2. NO Gas Detection Sensitivity (1) Initial Detection Sensitivity As the measurement NO gas, pure water and KOH aqueous solution were bubbled in this order in order to remove NO 2 gas and nitrates. Further, as the NO aqueous solution, an NO aqueous solution (1.9 mM) was prepared by purging 10 mL of pure water with Ar gas for several hours and then bubbling for 20 minutes in the presence of pure water and NO gas.
サイクリックボルタンメトリ（ＣＶ）による水溶液中ＮＯ濃度の測定を以下のようにして行った。作用電極としてＣｏ錯体−ＩＬ固定電極を、参照電極としてＡｇ／ＡｇＣｌ電極を、カウンタ電極として白金線を用い、ＣＶの測定用セルを作製した。電気化学測定は、ポテンショスタット（ＡＬＳ１０００Ｃ、ビー・エー・エス（株）製）により行った。水溶液中のＮＯ濃度を１０ｐｐｂ，５０ｐｐｂ，１００ｐｐｂ，１５０ｐｐｂ，２００ｐｐｂ，５００ｐｐｂ，１ｐｐｍ，２ｐｐｍ，５ｐｐｍ，１０ｐｐｍ及び０ｐｐｂ（ＮＯなし）としたものをそれぞれ用いて、ＣＶ測定を行った。その結果、ＮＯ濃度に応じて−０．６５Ｖ付近の電流値に変化が見られた。なお、スキャン速度は０．１Ｖｓ-1とし、支持電解質溶液としてＮａＣｌＯ4の０．１Ｍ水溶液を用いた。具体的には、ＮＯ濃度が１０ｐｐｂから５ｐｐｍまでは濃度の増加に伴い、電流値は直線的に大きくなることがわかった。The NO concentration in the aqueous solution was measured by cyclic voltammetry (CV) as follows. Using a Co complex-IL fixed electrode as a working electrode, an Ag/AgCl electrode as a reference electrode, and a platinum wire as a counter electrode, a CV measurement cell was prepared. The electrochemical measurement was performed with a potentiostat (ALS1000C, manufactured by BAS Co., Ltd.). CV measurement was carried out by using NO concentrations in the aqueous solution of 10 ppb, 50 ppb, 100 ppb, 150 ppb, 200 ppb, 500 ppb, 1 ppm, 2 ppm, 5 ppm, 10 ppm and 0 ppb (no NO), respectively. As a result, there was a change in the current value near -0.65 V depending on the NO concentration. The scan rate was 0.1 Vs -1, and a 0.1 M aqueous solution of NaClO 4 was used as the supporting electrolyte solution. Specifically, it was found that the current value increases linearly with increasing NO concentration from 10 ppb to 5 ppm.
（２）耐久試験後の検出感度
比較例１のガス検出用電極につき、先ほどと同様の手順でＣＶの測定用セルを作製した。その測定用セルにつき、水溶液中のＮＯ濃度を測定する前に、＋１．４Ｖと−１．４Ｖの間で電位を繰り返しスキャンさせた（５回繰り返した）。その後、水溶液中のＮＯ濃度を１００ｐｐｂとしたものを用いて、ＣＶ測定を行った。その結果、初期検出感度の測定時に確認された−０．６５Ｖ付近の電流値は確認されなくなった。(2) Detection Sensitivity After Endurance Test With respect to the gas detection electrode of Comparative Example 1, a CV measurement cell was prepared by the same procedure as above. Before measuring the NO concentration in the aqueous solution, the potential of the measurement cell was repeatedly scanned between +1.4 V and -1.4 V (repeated 5 times). After that, the CV measurement was performed using a solution in which the NO concentration in the aqueous solution was 100 ppb. As a result, the current value around -0.65 V confirmed at the time of measuring the initial detection sensitivity was not confirmed.
この結果から、比較例１のガス検出用電極は、電圧印加を繰り返すことにより表面に固定されたＣｏ錯体−ＩＬが表面から解離することがわかった。 From these results, it was found that in the gas detection electrode of Comparative Example 1, the Co complex-IL immobilized on the surface was dissociated from the surface by repeating the voltage application.
［実施例１］
１．ガス検出用電極
平均粒径０．３μｍの酸化チタン粉末を適量の分散剤とともに水に添加し超音波処理等によって分散させた、次に、一次粒子径が５〜１０ｎｍのチタニアゾルを添加混合し、製膜用のスラリーとした。次にスピンコートプロセスにより高速回転するアルミナ製の基板上に成膜スラリーを滴下し、乾燥後２００〜４００℃で熱処理することにより平均細孔径０．１μｍの多孔質酸化チタン膜(膜厚：１００μｍ)を作製し電極とした。基板にはその表面が金で被覆されたものを用いた。多孔質酸化チタン膜の作製にあたっては、スピンコートプロセスに限らずディッピング法、スプレー法、ドクターブレード法などを用いてもよい。得られた多孔質酸化チタン電極の単位体積当たりの表面積は約１０５ｃｍ2であった。[Example 1]
1. Gas Detection Electrode Titanium oxide powder having an average particle diameter of 0.3 μm was added to water together with an appropriate amount of a dispersant and dispersed by ultrasonication or the like. Next, titania sol having a primary particle diameter of 5 to 10 nm was added and mixed, The slurry was used for film formation. Next, a film-forming slurry is dropped on a substrate made of alumina that rotates at a high speed by a spin coating process, dried and then heat-treated at 200 to 400° C. to form a porous titanium oxide film having an average pore diameter of 0.1 μm (film thickness: 100 μm ) Was produced and used as an electrode. A substrate whose surface was coated with gold was used. In producing the porous titanium oxide film, not only the spin coating process but also a dipping method, a spray method, a doctor blade method or the like may be used. The surface area per unit volume of the obtained porous titanium oxide electrode was about 105 cm 2 .
続いて、多孔質酸化チタン電極を、ピラニア溶液（濃硫酸：３０％、過酸化水素水を３：１で混合）に２時間浸漬させた後に純水、メタノールで洗浄し、窒素ガスを吹き付けて速やかに乾燥させた。 Then, the porous titanium oxide electrode was immersed in a piranha solution (concentrated sulfuric acid: 30%, hydrogen peroxide solution was mixed at 3:1) for 2 hours, washed with pure water and methanol, and then sprayed with nitrogen gas. It was dried quickly.
次に、乾燥後の多孔質酸化チタン電極を、シランカップリング剤を混合したトルエン溶液（７０℃）に３時間程度浸漬させた。シランカップリング剤には信越化学工業製３−グリシドキシプロピルトリメトキシシラン（ＫＢＭ−４０３）を用いた。浸漬後、クロロホルム、水、メタノールで洗い流し、窒素ガスを吹き付けて速やかに乾燥させた。これにより、多孔質酸化チタン電極の表面に３−グリシドキシプロピルがシロキサン結合により固定化された。 Next, the dried porous titanium oxide electrode was immersed in a toluene solution (70° C.) mixed with a silane coupling agent for about 3 hours. As the silane coupling agent, 3-glycidoxypropyltrimethoxysilane (KBM-403) manufactured by Shin-Etsu Chemical Co., Ltd. was used. After the immersion, it was rinsed with chloroform, water, and methanol, and nitrogen gas was blown on it to quickly dry it. As a result, 3-glycidoxypropyl was immobilized on the surface of the porous titanium oxide electrode by the siloxane bond.
さらに、比較例１と同様にして、比較例１にて使用したジスルフィド基を有するＩＬをアミノ基に変えたＩＬ（式（１）参照）を溶かしたエタノール溶液中に、３−グリシドキシプロピルがシロキサン結合された多孔体酸化チタン電極を２時間浸漬した。これにより、ＩＬのアミノ基とグリシドとのエポキシ開環反応により、ＩＬのアミノ基がリンカー部（−ＣＨ2ＣＨ（ＯＨ）ＣＨ2ＯＣ3Ｈ6 ＳｉＯ−、但しＳｉはシロキサン結合を形成している）を介して多孔質酸化チタン電極に固定された。その後、過剰のＩＬを除くため、エタノール、クロロホルムで洗浄し、多孔質酸化チタン電極の表面にＩＬが固定された電極（ＩＬ固定多孔体電極）を得た。Further, in the same manner as in Comparative Example 1, 3-glycidoxypropyl was added to an ethanol solution containing IL (see Formula (1)) in which IL having a disulfide group used in Comparative Example 1 was changed to an amino group. The porous titanium oxide electrode having siloxane bonded thereto was immersed for 2 hours. As a result, the amino group of IL forms a linker portion (—CH 2 CH(OH)CH 2 OC 3 H 6 SiO—, but Si forms a siloxane bond by the epoxy ring-opening reaction of the amino group of IL and glycid. Is attached to the porous titanium oxide electrode. Then, in order to remove excess IL, it was washed with ethanol and chloroform to obtain an electrode having IL fixed on the surface of a porous titanium oxide electrode (IL fixed porous electrode).
最後に、比較例１と同様にして、Ｃｏ錯体（式（２）参照）を溶解させた水溶液中に上述のＩＬ固定多孔質電極を１週間浸漬した後、過剰のＣｏ錯体を除くため、ジメチルホルムアミド、アセトニトリル、純水で洗浄し、ＮＯ応答性のＣｏ錯体−ＩＬ固定多孔質電極（ガス検出用電極）を得た。こうして得られたガス検出用電極２０の模式図を図４に示す。なお、図４の符号は上述した実施形態で用いた符号と同じである。 Finally, in the same manner as in Comparative Example 1, the above IL-immobilized porous electrode was immersed for 1 week in an aqueous solution in which a Co complex (see formula (2)) was dissolved, and then dimethyl acetate was added to remove excess Co complex. It was washed with formamide, acetonitrile, and pure water to obtain a NO-responsive Co complex-IL fixed porous electrode (gas detection electrode). A schematic view of the gas detection electrode 20 thus obtained is shown in FIG. The reference numerals in FIG. 4 are the same as those used in the above-described embodiment.
２．ＮＯガス検出感度
（１）初期検出感度
比較例１と同様にして、実施例１のＣｏ錯体−ＩＬ固定多孔質電極を用いてＣＶの測定用セルを作製し、サイクリックボルタンメトリ（ＣＶ）による水溶液中ＮＯ濃度の測定を行った。その結果、ＮＯ濃度に応じて−０．６５Ｖ付近の電流値に変化が見られた。具体的には、ＮＯ濃度が１０ｐｐｂから２ｐｐｍまでは濃度の増加に伴い、電流値は直線的に大きくなることがわかった。また、ＮＯ濃度１００ｐｐｂにおける電流値は１０μＡであった。2. NO Gas Detection Sensitivity (1) Initial Detection Sensitivity As in Comparative Example 1, a CV measurement cell was prepared using the Co complex-IL fixed porous electrode of Example 1, and cyclic voltammetry (CV) was performed. The NO concentration in the aqueous solution was measured by. As a result, there was a change in the current value near -0.65 V depending on the NO concentration. Specifically, it was found that the current value linearly increases with increasing NO concentration from 10 ppb to 2 ppm. The current value at a NO concentration of 100 ppb was 10 μA.
（２）耐久試験後の検出感度
実施例１のガス検出用電極につき、先ほどと同様の手順でＣＶの測定用セルを作製した。その測定用セルにつき、水溶液中のＮＯ濃度を測定する前に、＋１．４Ｖと−１．４Ｖの間で電位を繰り返しスキャンさせた（５回繰り返した）。その後、水溶液中のＮＯ濃度を１００ｐｐｂとしたものを用いて、ＣＶ測定を行った。その結果、−０．６５Ｖ付近の電流値は、初期検出感度の測定時に確認された値（１０μＡ）と同等であった。(2) Detection Sensitivity After Endurance Test With respect to the gas detection electrode of Example 1, a CV measurement cell was produced by the same procedure as above. Before measuring the NO concentration in the aqueous solution, the potential of the measurement cell was repeatedly scanned between +1.4 V and -1.4 V (repeated 5 times). After that, the CV measurement was performed using a solution in which the NO concentration in the aqueous solution was 100 ppb. As a result, the current value near −0.65 V was equivalent to the value (10 μA) confirmed when the initial detection sensitivity was measured.
以上の結果から、実施例１のガス検出用電極は、電圧印加を繰り返した後も表面に固定されたＣｏ錯体−ＩＬが表面から解離せず、大きな酸化還元電位においてもガスを検出できることがわかった。これに対して、比較例１のガス検出用電極は、電圧印加を繰り返した後はガスを検出できなくなることがわかった。これは、実施例１ではイオン液体が結合力の強い共有結合を介して多孔質酸化チタン電極に結合していたのに対して、比較例１ではイオン液体が結合力の弱い硫黄原子と金との結合を介して金被膜に結合していたことによると考えられる。 From the above results, it is found that the gas detection electrode of Example 1 can detect the gas even at a large redox potential, since the Co complex-IL fixed on the surface does not dissociate from the surface even after repeated voltage application. It was On the other hand, it was found that the gas detection electrode of Comparative Example 1 could not detect the gas after repeated voltage application. This is because in Example 1, the ionic liquid was bonded to the porous titanium oxide electrode via a covalent bond having a strong bonding force, whereas in Comparative Example 1, the ionic liquid was composed of a sulfur atom having weak bonding force and gold. It is presumed that it was due to bonding to the gold coating through the bond of.
本発明は、ガスセンサに利用可能である。 INDUSTRIAL APPLICATION This invention can be utilized for a gas sensor.
１０ ガスセンサ、１２ 本体カバー、１２ａ 開口部、２０ ガス検出用電極、２１ 外部端子、２２ 構造体、２２ａ 孔、２３ カップリング剤、２４ リンカー部、２４ａ 中間部、２６ イオン液体、２８ 金属錯体、３０ カウンタ電極、３１ 外部端子、４０ 媒体、５０ 参照電極、６０ ガス、Ｂ１ 第１結合部位、Ｂ２ 第２結合部位。 10 gas sensor, 12 main body cover, 12a opening, 20 gas detection electrode, 21 external terminal, 22 structure, 22a hole, 23 coupling agent, 24 linker part, 24a intermediate part, 26 ionic liquid, 28 metal complex, 30 Counter electrode, 31 external terminal, 40 medium, 50 reference electrode, 60 gas, B1 first binding site, B2 second binding site.
Claims (6)
第１結合部位で前記構造体に共有結合するリンカー部と、
前記リンカー部のうち前記第１結合部位とは異なる第２結合部位で前記リンカー部と共有結合するイオン液体と、
特定のガスを選択的に捕捉する性質を持ち、前記イオン液体を介して固定化された金属錯体と、
を備え、
前記構造体は、導電性を有する金属酸化物の構造体である、
ガス検出用電極。 A structure having conductivity,
A linker portion covalently bonded to the structure at the first binding site,
An ionic liquid that is covalently bonded to the linker part at a second binding site different from the first binding site in the linker part;
Having a property of selectively capturing a specific gas, a metal complex immobilized via the ionic liquid,
Equipped with
The structure is a metal oxide structure having conductivity,
Gas detection electrode.
請求項１に記載のガス検出用電極。 The structure is a porous body,
The electrode for gas detection according to claim 1.
請求項１又は２に記載のガス検出用電極。 The metal oxide is one selected from the group consisting of titanium oxide, tin oxide, indium oxide, tungsten oxide and molybdenum oxide,
The electrode for gas detection according to claim 1.
請求項１〜３のいずれか１項に記載のガス検出用電極。 The combination of the ionic liquid and the metal complex is a combination of a phosphonium type ionic liquid and a tetracoordinated Co complex, or a combination of an ammonium type ionic liquid and a hexacoordinated Fe—Fe complex. Or a combination of a pyrrolidinium type ionic liquid and a tetracoordinate Ti complex, or a combination of an imidazolium type ionic liquid and a hexacoordinate Ru complex,
The electrode for gas detection according to claim 1.
前記ガス検出用電極と対をなすカウンタ電極と、
前記ガス検出用電極と前記カウンタ電極との隙間に充填され、検出対象ガスを含有可能な媒体と、
を備えたガスセンサ。 A gas detection electrode according to any one of claims 1 to 4,
A counter electrode paired with the gas detection electrode,
A medium that is filled in a gap between the gas detection electrode and the counter electrode, and can contain a gas to be detected,
Gas sensor.
請求項５に記載のガスセンサ。 The medium is an ionic liquid, water or an organic solvent medium,
The gas sensor according to claim 5.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2017/024988 WO2019008750A1 (en) | 2017-07-07 | 2017-07-07 | Gas detection electrode and gas sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPWO2019008750A1 JPWO2019008750A1 (en) | 2020-03-19 |
| JP6740478B2 true JP6740478B2 (en) | 2020-08-12 |
Family
ID=64950802
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2019528309A Active JP6740478B2 (en) | 2017-07-07 | 2017-07-07 | Gas detection electrode and gas sensor |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP6740478B2 (en) |
| WO (1) | WO2019008750A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7534204B2 (en) | 2019-12-13 | 2024-08-14 | 日本化学工業株式会社 | Coated particles and conductive materials containing same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7886577B2 (en) * | 2006-03-30 | 2011-02-15 | Oakland University | Devices with surface bound ionic liquids and method of use thereof |
| JP2010038840A (en) * | 2008-08-07 | 2010-02-18 | Sharp Corp | Chemical substance sensing element, chemical msubstance sensing apparatus, manufacturing method of surface decoration carbon nano structure, and manufacturing method of chemical substance sensing element |
-
2017
- 2017-07-07 JP JP2019528309A patent/JP6740478B2/en active Active
- 2017-07-07 WO PCT/JP2017/024988 patent/WO2019008750A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO2019008750A1 (en) | 2019-01-10 |
| JPWO2019008750A1 (en) | 2020-03-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Ali et al. | Ferrocene functionalized multi-walled carbon nanotubes as supercapacitor electrodes | |
| Kim et al. | Palladium oxide as a novel oxygen evolution catalyst on BiVO4 photoanode for photoelectrochemical water splitting | |
| Ensafi et al. | A new non-enzymatic glucose sensor based on copper/porous silicon nanocomposite | |
| Zhou et al. | Electrocatalytic CO2 reduction to formate at low overpotentials on electrodeposited Pd films: stabilized performance by suppression of CO formation | |
| Tajik et al. | Electrochemical detection of hydrazine by carbon paste electrode modified with ferrocene derivatives, ionic liquid, and CoS2-carbon nanotube nanocomposite | |
| Huang et al. | PdNi-and Pd-coated electrodes prepared by electrodeposition from ionic liquid for nonenzymatic electrochemical determination of ethanol and glucose in alkaline media | |
| Filanovsky et al. | Carbon electrodes modified with TiO2/metal nanoparticles and their application for the detection of trinitrotoluene | |
| Daemi et al. | An efficient platform for the electrooxidation of formaldehyde based on amorphous NiWO4 nanoparticles modified electrode for fuel cells | |
| Nugraha et al. | Block‐Copolymer‐Assisted Electrochemical Synthesis of Mesoporous Gold Electrodes: Towards a Non‐Enzymatic Glucose Sensor | |
| Shi et al. | Synergistic effect of the composite films formed by zeolitic imidazolate framework 8 (ZIF-8) and porous nickel films for enhanced amperometric sensing of hydrazine | |
| Xu et al. | Electrochemical preparation of a three dimensional PEDOT–Cu x O hybrid for enhanced oxidation and sensitive detection of hydrazine | |
| Gong et al. | Microperoxidase-11/metal–organic framework/macroporous carbon for detecting hydrogen peroxide | |
| Sivanesan et al. | Highly sensitive electrochemical sensor for nitric oxide using the self‐assembled monolayer of 1, 8, 15, 22‐Tetraaminophthalocyanatocobalt (II) on glassy carbon electrode | |
| Mazloum-Ardakani et al. | Carbon nanotubes in electrochemical sensors | |
| Hodgetts et al. | Electrocatalytic oxidation of hydrogen as an anode reaction for the Li-mediated N2 reduction to ammonia | |
| WO2019086556A1 (en) | A hybrid catalyst system for a water photooxidation process | |
| Hasan et al. | Selective detection of dopamine at the AACVD synthesized palladium nanoparticles and understanding the sensing mechanism through electrochemical and computational study | |
| Madrakian et al. | Preparation of a ZnO nanoparticles/multiwalled carbon nanotubes/carbon paste electrode as a sensitive tool for capecitabine determination in real samples | |
| Rajabzade et al. | Functionalized carbon nanotubes with gold nanoparticles to fabricate a sensor for hydrogen peroxide determination | |
| JP6740478B2 (en) | Gas detection electrode and gas sensor | |
| Faridan et al. | Simultaneous determination of Hg (II), Cd (II), Pb (II) and Zn (II) by anodic stripping voltammetry using modified carbon paste ionic liquid electrode | |
| Yan et al. | Microwave-assisted synthesis of carbon dots–zinc oxide/multi-walled carbon nanotubes and their application in electrochemical sensors for the simultaneous determination of hydroquinone and catechol | |
| JP4883796B2 (en) | Electrochemical measurement method | |
| Singh et al. | Highly efficient dopamine sensing with a carbon nanotube-encapsulated metal chalcogenide nanostructure | |
| Saito et al. | Oxygen plasma exfoliated vertically-aligned carbon nanotubes as electrodes for ultrasensitive stripping detection of Pb2+ |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20191009 |
|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20191009 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20200421 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20200616 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20200714 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20200722 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6740478 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |