JP2019052340A - Electrochemical cell, and photosynthesis apparatus - Google Patents
Electrochemical cell, and photosynthesis apparatus Download PDFInfo
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Abstract
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本発明は、電気化学セル及び光合成装置に関する。 The present invention relates to an electrochemical cell and a photosynthesis device.
半導体を光吸収体、金属錯体を二酸化炭素還元触媒として、半導体から金属錯体へ励起電子が移動することによって反応が進行する人工光合成デバイスが開示されている。太陽光エネルギーのみを用いて水（Ｈ２Ｏ）から水素（Ｈ２）を、水（Ｈ２Ｏ）と二酸化炭素（ＣＯ２）から一酸化炭素（ＣＯ），ギ酸（ＨＣＯＯＨ），アルコール（ＣＨ３ＯＨ）等を合成する人工光合成のためには、酸化／還元触媒間に約２Ｖの電位差を印加することが必要である。 There has been disclosed an artificial photosynthetic device in which a reaction proceeds by transferring excited electrons from a semiconductor to a metal complex using a semiconductor as a light absorber and a metal complex as a carbon dioxide reduction catalyst. Using only solar energy, water (H 2 O) to hydrogen (H 2 ), water (H 2 O) and carbon dioxide (CO 2 ) to carbon monoxide (CO), formic acid (HCOOH), alcohol (CH For the artificial photosynthesis that synthesizes (3OH) and the like, it is necessary to apply a potential difference of about 2 V between the oxidation / reduction catalysts.
これを実現するために、アモルファスシリコン系３接合太陽電池（ａ−Ｓｉ ３Ｊ−ＳＣ）の両面に酸化／還元触媒が担持された光電極が用いられている（非特許文献１，２）。また、アモルファスシリコン系３接合太陽電池を用い、裏面（光入射面の反対側）に還元触媒を担持し、これと対向するように酸化触媒機能を持つ部材を含んだ酸化電極を配置して太陽電池の表面電極と接続した、いわば太陽電池と電気化学セルを一体化した人工光合成セルが用いられている（非特許文献３）。また、より高い効率を狙って、ＩＩＩ−Ｖ族化合物２接合太陽電池（ＩＩＩ−Ｖ ２Ｊ−ＳＣ）を用いた例もある（非特許文献４）。 In order to realize this, photoelectrodes in which an oxidation / reduction catalyst is supported on both surfaces of an amorphous silicon-based three-junction solar cell (a-Si 3J-SC) are used (Non-Patent Documents 1 and 2). Further, an amorphous silicon-based three-junction solar cell is used, and a reduction catalyst is supported on the back surface (opposite the light incident surface), and an oxidation electrode including a member having an oxidation catalyst function is disposed so as to face the solar cell. An artificial photosynthesis cell in which a solar cell and an electrochemical cell are integrated, which is connected to the surface electrode of the battery, is used (Non-patent Document 3). Moreover, there is also an example using a III-V group compound two-junction solar cell (III-V 2J-SC) aiming at higher efficiency (Non-patent Document 4).
ところが、非特許文献１及び２では、３接合の太陽電池の両側に酸化触媒電極と還元電極を接合した構造が開示されている。還元電極には、ステンレススチールを用いており、還元電極側からは、酸化電極の水の酸化反応は目視で確認できない。したがって、還元電極側からは反応の不具合を確認することができない。一方、酸化電極側からは、透明導電膜付き（ＩＴＯ）ガラス基板上にナノ粒子触媒が形成されているため、水の酸化反応を確認できる。しかしながら、水溶液電解液と酸化電極を通過した光が太陽電池に照射されるため、太陽電池に照射される光強度が低下するため、変換効率が低くなる。 However, Non-Patent Documents 1 and 2 disclose a structure in which an oxidation catalyst electrode and a reduction electrode are bonded to both sides of a three-junction solar cell. Stainless steel is used for the reduction electrode, and the oxidation reaction of the oxidation electrode with water cannot be visually confirmed from the reduction electrode side. Therefore, the reaction failure cannot be confirmed from the reduction electrode side. On the other hand, from the oxidation electrode side, since the nanoparticle catalyst is formed on the (ITO) glass substrate with a transparent conductive film, the oxidation reaction of water can be confirmed. However, since the light that has passed through the aqueous electrolyte and the oxidation electrode is irradiated to the solar cell, the light intensity irradiated to the solar cell is reduced, so that the conversion efficiency is lowered.
また、非特許文献３及び４では、太陽電池は酸化電極と還元電極の外側にあり、水を通過せずに、直接太陽光が太陽電池に照射されるため、変換効率の低下はない。しかしながら、酸化電極、還元電極に不透明な金属電極を用いているため、電極の裏面からは水の酸化及び還元反応の様子を目視で確認できない。したがって、反応の不具合があっても、早急に確認できない欠点があった。 Moreover, in nonpatent literatures 3 and 4, since a solar cell exists in the outer side of an oxidation electrode and a reduction | restoration electrode, and sunlight is directly irradiated to a solar cell, without passing water, there is no fall of conversion efficiency. However, since an opaque metal electrode is used for the oxidation electrode and the reduction electrode, the state of the oxidation and reduction reaction of water cannot be visually confirmed from the back surface of the electrode. Therefore, there is a defect that even if there is a reaction failure, it cannot be confirmed immediately.
本発明の１つの態様は、酸化触媒機能を持つ部材を含む酸化電極と、還元触媒機能を持つ部材を含む還元電極と、が対向して設置されており、前記酸化電極及び前記還元電極の少なくとも一方が透光性を有し、前記酸化電極と前記還元電極との間に電解液が導入されていることを特徴とする電気化学セルである。 In one aspect of the present invention, an oxidation electrode including a member having an oxidation catalyst function and a reduction electrode including a member having a reduction catalyst function are disposed to face each other, and at least of the oxidation electrode and the reduction electrode One of the electrochemical cells is light-transmitting, and an electrolytic solution is introduced between the oxidation electrode and the reduction electrode.
ここで、前記酸化電極及び前記還元電極の少なくとも一方の可視光波長領域における透過率が２０％以上であることが好適である。 Here, it is preferable that the transmittance in the visible light wavelength region of at least one of the oxidation electrode and the reduction electrode is 20% or more.
また、前記酸化電極及び前記還元電極の間にバイアス電圧が印加されていることが好適である。 In addition, it is preferable that a bias voltage is applied between the oxidation electrode and the reduction electrode.
本発明の別の態様は、上記電気化学セルを備え、前記酸化電極及び前記還元電極の間に太陽電池が電気的に接続されており、前記太陽電池によって前記バイアス電圧が印加されている光合成装置である。 Another aspect of the present invention is a photosynthesizing device comprising the electrochemical cell, wherein a solar cell is electrically connected between the oxidation electrode and the reduction electrode, and the bias voltage is applied by the solar cell. It is.
ここで、前記電解液は、リン酸又はホウ酸緩衝水溶液であることが好適である。 Here, the electrolytic solution is preferably a phosphoric acid or boric acid buffer aqueous solution.
また、前記還元電極は、二酸化炭素（ＣＯ２）に対する還元機能を有し、前記酸化電極は、水（Ｈ２Ｏ）を酸化して酸素（Ｏ２）を発生させる酸化機能を有することが好適である。 The reduction electrode preferably has a function of reducing carbon dioxide (CO 2 ), and the oxidation electrode preferably has an oxidation function of oxidizing water (H 2 O) to generate oxygen (O 2 ). It is.
また、前記還元電極は、水（Ｈ２Ｏ）を還元して水素（Ｈ２）を発生させる酸化機能を有し、前記酸化電極は、水（Ｈ２Ｏ）を酸化して酸素（Ｏ２）を発生させる酸化機能を有することが好適である。 The reduction electrode has an oxidation function of reducing water (H 2 O) to generate hydrogen (H 2 ), and the oxidation electrode oxidizes water (H 2 O) to generate oxygen (O 2). It is preferable to have an oxidation function that generates).
本発明によれば、透光性を有する酸化電極又は還元電極を備えた電気化学セル及び光合成装置を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the electrochemical cell and photosynthesis apparatus provided with the oxidation electrode or reduction electrode which have translucency can be provided.
本発明の実施の形態における光合成装置１００は、図１に示すように、還元電極１０２、酸化電極１０４、電解液１０６、太陽電池セル１０８、窓材１１０及び枠材１１２を含んで構成される。 As shown in FIG. 1, the photosynthesis apparatus 100 according to the embodiment of the present invention includes a reduction electrode 102, an oxidation electrode 104, an electrolytic solution 106, a solar battery cell 108, a window material 110, and a frame material 112.
還元電極１０２は、還元反応によって物質を還元するために利用される電極である。還元電極１０２は、図２の断面模式図に示すように、基板１０、透明導電層１２、集電配線１４及び還元触媒１６を含んで構成される。なお、図２は模式図であり、各層の膜厚や幅等は実際のものとは異なっている。 The reduction electrode 102 is an electrode used for reducing a substance by a reduction reaction. As shown in the schematic cross-sectional view of FIG. 2, the reduction electrode 102 includes a substrate 10, a transparent conductive layer 12, a current collection wiring 14, and a reduction catalyst 16. FIG. 2 is a schematic diagram, and the thickness and width of each layer are different from the actual ones.
基板１０は、還元電極１０２を構造的に支持する部材である。基板１０は、特に材料が限定されるものではないが、還元電極１０２を透光性を有するようにするには、例えば、ガラス基板やプラスチック等とすることが好適である。 The substrate 10 is a member that structurally supports the reduction electrode 102. The material of the substrate 10 is not particularly limited. However, in order to make the reduction electrode 102 have translucency, for example, a glass substrate or plastic is preferable.
透明導電層１２は、還元電極１０２における集電を効果的にするために設けられる。透明導電層１２は、特に限定されるものではないが、酸化インジウム錫（ＩＴＯ）、フッ素ドープ酸化錫（ＦＴＯ）、酸化亜鉛（ＺｎＯ）等とすることが好適である。特に、熱的及び化学的な安定性を考慮するとフッ素ドープ酸化錫（ＦＴＯ）を用いることが好適である。 The transparent conductive layer 12 is provided to effectively collect current at the reduction electrode 102. The transparent conductive layer 12 is not particularly limited, but is preferably indium tin oxide (ITO), fluorine-doped tin oxide (FTO), zinc oxide (ZnO), or the like. In particular, it is preferable to use fluorine-doped tin oxide (FTO) in consideration of thermal and chemical stability.
集電配線１４は、還元電極１０２における集電の効果を高めるために設けられる。すなわち、還元電極１０２を大面積化した場合、透明導電層１２のみでは還元電極１０２の全面において十分な反応を促進させるための導電性を確保できなくなるので、還元電極１０２の導電性を高めるために設けられる。集電配線１４は、例えば、間隔を置いて櫛形状に配置された線状のフィンガー電極と、フィンガー電極を更に集電するためのバス電極とを組み合わせた構成とすることができる。集電配線１４は、導電部１４ａ、第１シール部１４ｂ及び第２シール部１４ｃから構成することが好適である。導電部１４ａは、導電性の高い材料で構成され、金属を含む材料で構成することが好適である。例えば、銀（Ａｇ）、銅（Ｃｕ）等を含む材料で構成することが好適である。また、第１シール部１４ｂ及び第２シール部１４ｃは、導電部１４ａを化学的及び機械的に保護するために少なくとも導電部１４ａの一部を被覆するように設けられる。第１シール部１４ｂは、低融点のガラスコート材とすることができる。また、第２シール部１４ｃは、シリコーンゴム（脱オキシムタイプ、低分子シロキサン低減材、耐油・耐溶剤フロロシリコーン等）、ポリイソブチレン、ポリプロピレン、メタクリル（アクリル）、ポリカーボネート、フッ素樹脂（テフロン（登録商標））、エポキシ樹脂等の樹脂とすることができる。 The current collection wiring 14 is provided to enhance the effect of current collection at the reduction electrode 102. That is, when the reduction electrode 102 is increased in area, the transparent conductive layer 12 alone cannot secure sufficient conductivity for promoting the reaction over the entire surface of the reduction electrode 102, so that the conductivity of the reduction electrode 102 can be increased. Provided. The current collection wiring 14 can be configured, for example, by combining linear finger electrodes arranged in a comb shape at intervals and a bus electrode for further collecting the finger electrodes. The current collecting wiring 14 is preferably composed of a conductive portion 14a, a first seal portion 14b, and a second seal portion 14c. The conductive portion 14a is made of a highly conductive material, and is preferably made of a material containing metal. For example, it is preferable to use a material containing silver (Ag), copper (Cu), or the like. The first seal portion 14b and the second seal portion 14c are provided so as to cover at least a part of the conductive portion 14a in order to protect the conductive portion 14a chemically and mechanically. The first seal portion 14b can be a glass coating material having a low melting point. The second seal portion 14c is made of silicone rubber (deoxime type, low molecular siloxane reducing material, oil / solvent resistant fluorosilicone, etc.), polyisobutylene, polypropylene, methacryl (acrylic), polycarbonate, fluororesin (Teflon (registered trademark)). )), A resin such as an epoxy resin.
還元触媒１６は、還元触媒機能を有する材料を含んで構成される。還元触媒機能を有する材料は、例えば、白金（Ｐｔ）とすることができる。白金は、ナノコロイド溶液として集電配線１４が形成された透明導電層１２の表面上に担持することができる（例：国際特許公開ＷＯ２００５／０２３４６７Ａ１）。 The reduction catalyst 16 includes a material having a reduction catalyst function. The material having a reduction catalyst function can be, for example, platinum (Pt). Platinum can be supported as a nanocolloid solution on the surface of the transparent conductive layer 12 on which the current collector wiring 14 is formed (for example, International Patent Publication WO2005 / 023467A1).
酸化電極１０４は、酸化反応によって物質を酸化するために利用される電極である。酸化電極１０４は、図３の断面模式図に示すように、基板２０、透明導電層２２、集電配線２４及び酸化触媒２６を含んで構成される。なお、図３は模式図であり、各層の膜厚や幅等は実際のものとは異なっている。 The oxidation electrode 104 is an electrode used for oxidizing a substance by an oxidation reaction. As shown in the schematic cross-sectional view of FIG. 3, the oxidation electrode 104 includes a substrate 20, a transparent conductive layer 22, a current collection wiring 24, and an oxidation catalyst 26. FIG. 3 is a schematic diagram, and the thickness and width of each layer are different from the actual ones.
基板２０は、酸化電極１０４を構造的に支持する部材である。基板２０は、特に材料が限定されるものではないが、酸化電極１０４を透光性を有するようにするには、例えば、ガラス基板やプラスチック等とすることが好適である。 The substrate 20 is a member that structurally supports the oxidation electrode 104. The material of the substrate 20 is not particularly limited. However, in order to make the oxidation electrode 104 have translucency, for example, a glass substrate or plastic is preferable.
透明導電層２２は、酸化電極１０４における集電を効果的にするために設けられる。透明導電層２２は、特に限定されるものではないが、酸化インジウム錫（ＩＴＯ）、フッ素ドープ酸化錫（ＦＴＯ）、酸化亜鉛（ＺｎＯ）等とすることが好適である。特に、熱的及び化学的な安定性を考慮するとフッ素ドープ酸化錫（ＦＴＯ）を用いることが好適である。 The transparent conductive layer 22 is provided to effectively collect current at the oxidation electrode 104. The transparent conductive layer 22 is not particularly limited, but is preferably made of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), zinc oxide (ZnO), or the like. In particular, it is preferable to use fluorine-doped tin oxide (FTO) in consideration of thermal and chemical stability.
集電配線２４は、酸化電極１０４における集電の効果を高めるために設けられる。すなわち、酸化電極１０４を大面積化した場合、透明導電層２２のみでは酸化電極１０４の全面において十分な反応を促進させるための導電性を確保できなくなるので、酸化電極１０４の導電性を高めるために設けられる。集電配線２４は、例えば、間隔を置いて櫛形状に配置された線状のフィンガー電極と、フィンガー電極を更に集電するためのバス電極とを組み合わせた構成とすることができる。集電配線２４は、導電部２４ａ、第１シール部２４ｂ及び第２シール部２４ｃから構成することが好適である。導電部２４ａは、導電性の高い材料で構成され、金属を含む材料で構成することが好適である。例えば、銀（Ａｇ）、銅（Ｃｕ）等を含む材料で構成することが好適である。また、第１シール部２４ｂ及び第２シール部２４ｃは、導電部２４ａを化学的及び機械的に保護するために少なくとも導電部２４ａの一部を被覆するように設けられる。第１シール部２４ｂは、低融点のガラスコート材とすることができる。また、第２シール部２４ｃは、シリコーンゴム（脱オキシムタイプ、低分子シロキサン低減材、耐油・耐溶剤フロロシリコーン等）、ポリイソブチレン、ポリプロピレン、メタクリル（アクリル）、ポリカーボネート、フッ素樹脂（テフロン（登録商標））、エポキシ樹脂等の樹脂とすることができる。 The current collection wiring 24 is provided to enhance the effect of current collection in the oxidation electrode 104. That is, when the area of the oxidation electrode 104 is increased, the conductivity for promoting the reaction sufficiently on the entire surface of the oxidation electrode 104 cannot be ensured only by the transparent conductive layer 22. Provided. The current collection wiring 24 can be configured, for example, by combining linear finger electrodes arranged in a comb shape at intervals and a bus electrode for further collecting the finger electrodes. The current collecting wiring 24 is preferably composed of a conductive portion 24a, a first seal portion 24b, and a second seal portion 24c. The conductive portion 24a is made of a highly conductive material, and is preferably made of a material containing metal. For example, it is preferable to use a material containing silver (Ag), copper (Cu), or the like. The first seal part 24b and the second seal part 24c are provided so as to cover at least a part of the conductive part 24a in order to protect the conductive part 24a chemically and mechanically. The first seal portion 24b can be a glass coating material having a low melting point. The second seal portion 24c is made of silicone rubber (deoxime type, low molecular siloxane reducing material, oil / solvent-resistant fluorosilicone, etc.), polyisobutylene, polypropylene, methacrylic (acrylic), polycarbonate, fluororesin (Teflon (registered trademark)). )), A resin such as an epoxy resin.
酸化触媒２６は、酸化触媒機能を有する材料を含んで構成される。酸化触媒機能を有する材料は、例えば、酸化イリジウム（ＩｒＯｘ）を含む材料とすることができる。酸化イリジウムは、ナノコロイド溶液として集電配線２４が形成された透明導電層２２の表面上に担持することができる(T.Arai et.al, Energy Environ. Sci 8, 1998 (2015))。 The oxidation catalyst 26 includes a material having an oxidation catalyst function. The material having an oxidation catalyst function can be, for example, a material containing iridium oxide (IrOx). Iridium oxide can be supported on the surface of the transparent conductive layer 22 on which the current collector wiring 24 is formed as a nanocolloid solution (T. Arai et.al, Energy Environ. Sci 8, 1998 (2015)).
このように、本実施の形態では、還元電極１０２及び酸化電極１０４を可視光波長領域において透光性を有する構成とすることができる。ここで、可視光波長領域とは、４００ｎｍ以上７００ｎｍ以下の光の波長領域とする。また、可視光波長領域において透光性を有するとは、４００ｎｍ以上７００ｎｍ以下の光の波長領域において還元電極１０２及び酸化電極１０４に入射した光のうち少なくとも２０％以上を透過することを意味するものとする。 Thus, in this embodiment mode, the reduction electrode 102 and the oxidation electrode 104 can have a light-transmitting property in the visible light wavelength region. Here, the visible light wavelength region is a wavelength region of light of 400 nm to 700 nm. In addition, having translucency in the visible light wavelength region means that at least 20% or more of light incident on the reduction electrode 102 and the oxidation electrode 104 is transmitted in the wavelength region of light of 400 nm to 700 nm. And
なお、還元電極１０２及び酸化電極１０４の両方を可視光波長領域において透光性を有する構成とすることなく、少なくとも１つを可視光波長領域において透光性を有する構成とすればよい。この場合、還元電極１０２及び酸化電極１０４のうち透光性を持たないものは、従来の還元電極１０２又は酸化電極１０４とすればよい。還元電極１０２及び酸化電極１０４の少なくとも１つを可視光波長領域において透光性を有する構成とすることで、光合成装置１００における反応を目視で確認できるようになる。具体的には、反応の不具合を目視にて確認することができ、早急に対応できるようになる。 Note that at least one of the reduction electrode 102 and the oxidation electrode 104 may have a light-transmitting property in the visible light wavelength region without using a light-transmitting property in the visible light wavelength region. In this case, the reduction electrode 102 and the oxidation electrode 104 that do not have translucency may be the conventional reduction electrode 102 or oxidation electrode 104. By setting at least one of the reduction electrode 102 and the oxidation electrode 104 to have a light-transmitting property in the visible light wavelength region, the reaction in the photosynthesis apparatus 100 can be visually confirmed. Specifically, the reaction failure can be visually confirmed, and it becomes possible to respond quickly.
本実施の形態における光合成装置１００は、還元電極１０２と酸化電極１０４を組み合わせて構成される。例えば、図１に示すように、還元電極１０２と酸化電極１０４を還元触媒１６及び酸化触媒２６が対向するように配置し、その間に反応物が溶解された電解液１０６を導入させる。反応物は、炭化化合物とすることができ、例えば、二酸化炭素（ＣＯ２）とすることができる。また、電解液は、リン酸緩衝水溶液やホウ酸緩衝水溶液とすることが好適である。具体的な構成例では、二酸化炭素（ＣＯ２）飽和リン酸緩衝液のタンクを設け、ポンプによって当該液を還元電極１０２と酸化電極１０４との間に設けられた間隙に供給し、還元反応によって生じたギ酸（ＨＣＯＯＨ）や酸素（Ｏ２）を外部の燃料タンクに回収する。 Photosynthesis apparatus 100 in the present embodiment is configured by combining reduction electrode 102 and oxidation electrode 104. For example, as shown in FIG. 1, the reduction electrode 102 and the oxidation electrode 104 are arranged so that the reduction catalyst 16 and the oxidation catalyst 26 face each other, and an electrolytic solution 106 in which a reactant is dissolved is introduced therebetween. The reactant can be a carbonized compound, for example, carbon dioxide (CO 2 ). The electrolyte is preferably a phosphate buffer aqueous solution or a borate buffer aqueous solution. In a specific configuration example, a tank of carbon dioxide (CO 2 ) saturated phosphate buffer is provided, and the liquid is supplied to a gap provided between the reduction electrode 102 and the oxidation electrode 104 by a pump, and a reduction reaction is performed. The generated formic acid (HCOOH) and oxygen (O 2 ) are recovered in an external fuel tank.
還元電極１０２と酸化電極１０４との間を電気的に接続し、適切なバイアス電圧を印加した状態とする。バイアス電圧を印加する手段は、特に限定されるものではなく、化学的電池（一次電池、二次電池等を含む）、定電圧源、太陽電池等が挙げられる。このとき、酸化電極１０４の集電配線２４に正極が接続され、還元電極１０２の集電配線１４に負極が接続される。 The reduction electrode 102 and the oxidation electrode 104 are electrically connected, and an appropriate bias voltage is applied. The means for applying the bias voltage is not particularly limited, and examples thereof include a chemical battery (including a primary battery and a secondary battery), a constant voltage source, and a solar battery. At this time, the positive electrode is connected to the current collector wiring 24 of the oxidation electrode 104, and the negative electrode is connected to the current collector wiring 14 of the reduction electrode 102.
本実施の形態では、太陽電池セル１０８を採用している。太陽電池セル１０８は、還元電極１０２及び酸化電極１０４に隣接して配置することができる。図１の例では、還元電極１０２と酸化電極１０４とを対向させた電気化学セルの還元電極１０２の背面に太陽電池セル１０８を配置し、太陽電池セル１０８の正極を酸化電極１０４に接続し、負極を還元電極１０２に接続している。 In the present embodiment, the solar battery cell 108 is employed. The solar battery cell 108 can be disposed adjacent to the reduction electrode 102 and the oxidation electrode 104. In the example of FIG. 1, the solar cell 108 is disposed on the back surface of the reduction electrode 102 of the electrochemical cell in which the reduction electrode 102 and the oxidation electrode 104 are opposed to each other, and the positive electrode of the solar cell 108 is connected to the oxidation electrode 104. The negative electrode is connected to the reduction electrode 102.
二酸化炭素（ＣＯ２）からギ酸（ＨＣＯＯＨ）等を合成する場合、水（Ｈ２Ｏ）は酸化されて二酸化炭素（ＣＯ２）に電子とプロトンを供給する。ｐＨ７付近では水（Ｈ２Ｏ）の酸化電位は０．８２Ｖ、還元電位は−０．４１Ｖ（何れもＮＨＥ）である。また、二酸化炭素（ＣＯ２）から一酸化炭素（ＣＯ）、ギ酸（ＨＣＯＯＨ）、メチルアルコール（ＣＨ３ＯＨ）への還元電位はそれぞれ−０．５３Ｖ，−０．６１Ｖ，−０．３８Ｖである。したがって、酸化電位と還元電位の電位差は１．２０〜１．４３Ｖである。そこで、炭化化合物である二酸化炭素（ＣＯ２）を還元する場合、太陽電池セル１０８は、４つの結晶系シリコン太陽電池を直接に接続した結晶シリコン系４接合太陽電池や３つのアモルファス系シリコン太陽電池を直列に接続したアモルファスシリコン系３接合太陽電池とすることが好適である。 When synthesizing formic acid (HCOOH) or the like from carbon dioxide (CO 2 ), water (H 2 O) is oxidized to supply electrons and protons to carbon dioxide (CO 2 ). In the vicinity of pH 7, the oxidation potential of water (H 2 O) is 0.82 V, and the reduction potential is −0.41 V (both are NHE). The reduction potentials from carbon dioxide (CO 2 ) to carbon monoxide (CO), formic acid (HCOOH), and methyl alcohol (CH 3 OH) are −0.53 V, −0.61 V, and −0.38 V, respectively. . Therefore, the potential difference between the oxidation potential and the reduction potential is 1.20 to 1.43V. Therefore, when carbon dioxide (CO 2 ), which is a carbonized compound, is reduced, the solar battery cell 108 includes a crystalline silicon-based four-junction solar cell or three amorphous silicon solar cells in which four crystalline silicon solar cells are directly connected. It is preferable to form amorphous silicon-based three-junction solar cells connected in series.
ここで、還元電極１０２及び酸化電極１０４の両方が可視光波長領域にて透光性を有する場合、太陽電池セル１０８はいずれの側に配置してもよい。一方、還元電極１０２及び酸化電極１０４の一方のみが可視光波長領域にて透光性を有する場合、太陽電池セル１０８は可視光波長領域にて透光性を持たない側に配置することが好適である。すなわち、可視光波長領域にて透光性を有する側に太陽電池セル１０８を配置しないことによって、太陽電池セル１０８によって目視の視界を遮られることがなくなる。 Here, when both the reduction electrode 102 and the oxidation electrode 104 have translucency in the visible light wavelength region, the solar battery cell 108 may be disposed on either side. On the other hand, when only one of the reduction electrode 102 and the oxidation electrode 104 has a light-transmitting property in the visible light wavelength region, the solar battery cell 108 is preferably disposed on the side that does not have a light-transmitting property in the visible light wavelength region. It is. That is, when the solar battery cell 108 is not disposed on the side having translucency in the visible light wavelength region, the visual field of view is not blocked by the solar battery cell 108.
太陽電池セル１０８に対しては、受光面側に窓材１１０を設けることが好適である。窓材１１０は、太陽電池セル１０８を保護する部材である。窓材１１０は、太陽電池セル１０８において発電に寄与する波長の光を透過する部材とし、例えば、ガラス、プラスチック等とすることができる。 For the solar battery cell 108, it is preferable to provide a window member 110 on the light receiving surface side. The window material 110 is a member that protects the solar battery cell 108. The window member 110 is a member that transmits light having a wavelength that contributes to power generation in the solar battery cell 108, and may be glass, plastic, or the like, for example.
還元電極１０２、酸化電極１０４、太陽電池セル１０８及び窓材１１０は、枠材１１２によって構造的に支持される。 The reduction electrode 102, the oxidation electrode 104, the solar battery cell 108, and the window material 110 are structurally supported by the frame material 112.
［実施例］
＜酸化電極の作製方法＞
まず、酸化イリジウム（ＩｒＯｘ）のナノコロイドを合成した(T. Arai, S. Sato, and T. Morikawa, Energy Environ. Sci 8, 1998 (2015))。２ｍＭの塩化イリジウム酸（ＩＶ）カリウム（Ｋ２ＩｒＣｌ６）水溶液５０ｍｌに１０ｗｔ％の水酸化ナトリウム（ＮａＯＨ）水溶液を加えてｐＨ１３に調整した黄色溶液を、ホットスターラーを用いて９０℃で２０分加熱した。これによって得られた青色溶液を氷水で１時間冷却した。さらに、冷やした溶液（２０ｍｌ）に３Ｍ硝酸（ＨＮＯ３）を滴下してｐＨ１に調整し、８０分攪拌し、酸化イリジウム（ＩｒＯｘ）のナノコロイド水溶液を得た。この溶液に１．５ｗｔ％ＮａＯＨ水溶液（１−２ｍｌ）を滴下してｐＨ１２に調整した。
[Example]
<Production method of oxidation electrode>
First, nano colloids of iridium oxide (IrOx) were synthesized (T. Arai, S. Sato, and T. Morikawa, Energy Environ. Sci 8, 1998 (2015)). A yellow solution adjusted to pH 13 by adding 10 wt% aqueous sodium hydroxide (NaOH) solution to 50 ml of 2 mM potassium (IV) chloroiridate (K 2 IrCl 6 ) solution was heated at 90 ° C. for 20 minutes using a hot stirrer. did. The resulting blue solution was cooled with ice water for 1 hour. Further, 3M nitric acid (HNO 3 ) was added dropwise to the cooled solution (20 ml) to adjust the pH to 1 and stirred for 80 minutes to obtain an aqueous iridium oxide (IrOx) nanocolloid solution. To this solution, 1.5 wt% NaOH aqueous solution (1-2 ml) was added dropwise to adjust the pH to 12.
本実施例では、基板２０及び透明導電層２２は、ＩＴＯより化学的及び熱的に安定性が高いフッ素ドープ酸化錫（ＦＴＯ）透明導電膜付きのガラス（日本板硝子製ＳＡ−２５）を用いた。ＦＴＯである透明導電層２２上に、スクリーン印刷を適用して、銀（Ａｇ）のペーストを所望のパターンに塗布して、大気中において熱処理４５０℃を施して銀（Ａｇ）を焼結させて導電部２４ａを形成した。さらに、銀（Ａｇ）の配線上に、スクリーン印刷法を適用して、低融点ガラスペーストを用いてカバーガラスを塗布し、大気中において熱処理（４００℃）を施してカバーガラスを第１シール部２４ｂとして形成した。その上に、ディスペンサーを用いてシリコーン樹脂（ゴム）を塗布して、室温で乾燥させて第２シール部２４ｃを形成した。これによって、３層構造の集電配線２４を作製した。 In this example, the substrate 20 and the transparent conductive layer 22 were made of glass (SA-25 manufactured by Nippon Sheet Glass) with a fluorine-doped tin oxide (FTO) transparent conductive film that is chemically and thermally more stable than ITO. . On the transparent conductive layer 22 which is FTO, screen printing is applied, a silver (Ag) paste is applied in a desired pattern, and heat treatment is performed at 450 ° C. in the atmosphere to sinter the silver (Ag). A conductive portion 24a was formed. Further, a screen printing method is applied to the silver (Ag) wiring, a cover glass is applied using a low-melting glass paste, and heat treatment (400 ° C.) is performed in the atmosphere to cover the cover glass with the first seal portion. 24b was formed. A silicone resin (rubber) was applied thereon using a dispenser and dried at room temperature to form the second seal portion 24c. As a result, a current collecting wiring 24 having a three-layer structure was produced.
このように、集電配線２４が形成された透明導電層２２上にｐＨ１２に調整した酸化イリジウム（ＩｒＯｘ）のナノコロイド水溶液を塗布し、乾燥炉内において６０℃で４０分間保持して乾燥した。乾燥後、析出した塩を超純水で洗浄し、酸化触媒２６を形成した。このようにして、１０ｃｍ×１０ｃｍの大きさの酸化電極１０４を得た。このとき、酸化イリジウム（ＩｒＯｘ）のナノコロイド水溶液の塗布量（２５ｍｌ×１回、２回、３回／１０ｃｍ角）を変えて、３種類の酸化電極１０４を形成した。 Thus, the nano colloid aqueous solution of iridium oxide (IrOx) adjusted to pH 12 was apply | coated on the transparent conductive layer 22 in which the current collection wiring 24 was formed, and it dried by hold | maintaining at 60 degreeC for 40 minute (s) in a drying furnace. After drying, the precipitated salt was washed with ultrapure water to form an oxidation catalyst 26. In this way, an oxidation electrode 104 having a size of 10 cm × 10 cm was obtained. At this time, three types of oxidation electrodes 104 were formed by changing the amount of iridium oxide (IrOx) nanocolloid aqueous solution applied (25 ml × 1, 2 times, 3 times / 10 cm square).
＜還元電極の作製方法１＞
本実施例では、還元電極１０２は透光性をもたないルテニウム錯体ポリマー（ＲｕＣＰ）担持多孔質炭素還元電極（サイズ：１０ｃｍ×１０ｃｍ）とした（T. Arai, S. Sato, and T. Morikawa, Energy Environ. Sci 8, 1998 (2015)）。
<Production Method 1 of Reduction Electrode>
In this embodiment, the reduction electrode 102 is a ruthenium complex polymer (RuCP) -supporting porous carbon reduction electrode (size: 10 cm × 10 cm) having no translucency (T. Arai, S. Sato, and T. Morikawa). , Energy Environ. Sci 8, 1998 (2015)).
まず、管状炉を用いて、多孔質炭素をアルゴン（Ａｒ）の雰囲気下において３５０℃で２時間予備加熱した。その多孔質炭素の表面上に、二酸化炭素（ＣＯ２）の還元触媒であるＲｕ錯体ポリマー（ＲｕＣＰ）を修飾した。具体的には、２５ｍｇの［Ｒｕ｛４，４’−ｄｉ（１Ｈ−ｐｒｒｒｏｌｙｌ−３−ｐｒｏｐｙｌｃａｒｂｏｎａｔｅ）−２，２’−ｂｉｐｙｒｉｄｉｎｅ｝（ＣＯ）（ＭｅＣＮ）Ｃｌ２］を３５ｍｌのアセトニトリル（ＭｅＣＮ）に溶解させてＲｕ錯体溶液を調製した。そして、２．５μｌのピロールを５０ｍｌのＭｅＣＮに溶解させた１．８４ｍｌのピロール溶液をＲｕ錯体溶液に投入後、塩化鉄（ＩＩＩ）（ＦｅＣｌ３）をエタノールに溶解した９ｍｌの０．２ＭＦｅＣｌ３溶液を滴下して混合した。ＦｅＣｌ３溶液の添加により、Ｆｅイオンによりピロールの重合反応を促進させて、Ｒｕ錯体ポリマー（ＲｕＣＰ）溶液が調製されたことで、Ｒｕ錯体溶液は赤色から黒色に変化した。このように生成された本溶液を４．６ｍｌ／１回の量で多孔質炭素担体に塗布して、常温で５分間真空乾燥した。この塗布、真空乾燥処理を１０回繰り返した。その後、超純水で洗浄して余分なＦｅＣｌ３を除去して乾燥した後、ＲｕＣＰで修飾された多孔質炭素担体を作製した。 First, using a tubular furnace, porous carbon was preheated at 350 ° C. for 2 hours in an argon (Ar) atmosphere. On the surface of the porous carbon, a Ru complex polymer (RuCP) which is a reduction catalyst of carbon dioxide (CO 2 ) was modified. Specifically, 25 mg of [Ru {4,4′-di (1H-propyl-3-propylcarbonate) -2,2′-bipyridine] (CO) (MeCN) Cl 2 ] in 35 ml of acetonitrile (MeCN). A Ru complex solution was prepared by dissolution. Then, after turning the pyrrole solution of 1.84ml dissolved pyrrole of 2.5μl in MeCN in 50ml of Ru complex solution, 0.2MFeCl 3 solution 9ml of iron (III) chloride and (FeCl 3) were dissolved in ethanol Were added dropwise and mixed. By adding the FeCl 3 solution, the polymerization reaction of pyrrole was promoted by Fe ions, and the Ru complex polymer (RuCP) solution was prepared, so that the Ru complex solution changed from red to black. The solution thus produced was applied to a porous carbon support in an amount of 4.6 ml / time and vacuum dried at room temperature for 5 minutes. This coating and vacuum drying treatment was repeated 10 times. Subsequently, after washing with ultrapure water to remove excess FeCl 3 and drying, a porous carbon support modified with RuCP was produced.
続いて、ＦＴＯである透明導電層上に、スクリーン印刷を適用して、銀（Ａｇ）のペーストを所望のパターンに塗布して、大気中において熱処理４５０℃を施して銀（Ａｇ）を焼結させて導電部を形成した。さらに、銀（Ａｇ）の配線上に、スクリーン印刷法を適用して、低融点ガラスペーストを用いてカバーガラスを塗布し、大気中において熱処理（４００℃）を施してカバーガラスを第１シール部として形成した。その上に、ディスペンサーを用いてシリコーン樹脂（ゴム）を塗布して、室温で乾燥させて第２シール部を形成した。これによって、３層構造の集電配線を作製した。そして、グラファイト系導電性接着剤を用いて、ルテニウム錯体ポリマー（ＲｕＣＰ）担持多孔質炭素を上記３層構造の集電配線付きＦＴＯ基板上に貼りつけた。 Subsequently, screen printing is applied to the transparent conductive layer, which is an FTO, a silver (Ag) paste is applied in a desired pattern, and heat treatment is performed at 450 ° C. in the atmosphere to sinter the silver (Ag). Thus, a conductive portion was formed. Further, a screen printing method is applied to the silver (Ag) wiring, a cover glass is applied using a low-melting glass paste, and heat treatment (400 ° C.) is performed in the atmosphere to cover the cover glass with the first seal portion. Formed as. A silicone resin (rubber) was applied thereon using a dispenser, and dried at room temperature to form a second seal portion. Thus, a current collecting wiring having a three-layer structure was produced. And ruthenium complex polymer (RuCP) carrying porous carbon was affixed on the FTO board | substrate with the current collection wiring of the said 3 layer structure using the graphite type conductive adhesive.
＜還元電極の作製方法２＞
透光性を有する還元電極１０２の実施例としてナノ粒子のＰｔを担持した電極を作製した。すなわち、透光性を有する水電解による水素生成用の還元電極１０２を作成した。
<Production Method 2 of Reduction Electrode>
As an example of the reducing electrode 102 having translucency, an electrode carrying Pt of nanoparticles was produced. That is, a reduction electrode 102 for producing hydrogen by water electrolysis having translucency was prepared.
基板１０及び透明導電層１２は、フッ素ドープ酸化錫（ＦＴＯ）透明導電膜付きのガラスを用いた。塩化白金酸（Ｈ２ＰｔＣｌ６）のイソプロパノール溶液（濃度０．００５ｍｏｌ／ｌ）を調製し、スピンコート法（回転数：３００回転３０秒後６００回転１分）で透明導電層１２上に塗布した。塗布後、大気中４００℃１０分焼成した。本手法で、透明導電層１２が設けられた基板１０上に粒径２〜１０ｎｍのナノ粒子Ｐｔが担持された。 As the substrate 10 and the transparent conductive layer 12, glass with a fluorine-doped tin oxide (FTO) transparent conductive film was used. An isopropanol solution (concentration 0.005 mol / l) of chloroplatinic acid (H 2 PtCl 6 ) was prepared and applied onto the transparent conductive layer 12 by spin coating (rotation speed: 300 rotations 30 seconds and then 600 rotations 1 minute). . After the application, it was baked in the atmosphere at 400 ° C. for 10 minutes. In this method, nanoparticles Pt having a particle diameter of 2 to 10 nm were supported on the substrate 10 provided with the transparent conductive layer 12.
＜電気化学特性評価＞
本実施例では、二酸化炭素（ＣＯ２）還元反応と水（Ｈ２Ｏ）の酸化反応の電気化学特性の評価を行った。上記方法で形成した酸化電極（アノード電極）１０４とルテニウム錯体ポリマー（ＲｕＣＰ）担持多孔質炭素還元電極（カソード電極）を対向させて、その間隙にリン酸緩衝水溶液中で二酸化炭素（ＣＯ２）ガスをバブリングしながら供給した。リン酸緩衝水溶液は、Ｋ２ＨＰＯ４とＫＨ２ＰＯ４をモル比１：１で混合し、リン酸濃度０．１Ｍになるように超純水を用いて調製した。二酸化炭素（ＣＯ２）の還元反応と水（Ｈ２Ｏ）の酸化反応は、電気化学測定システム（北斗電工製ＨＡ−３００１Ａ）を用いて定電流モードで制御した。このとき、還元電極１０２と酸化電極１０４とを太陽電池セル１０８を介して接続した光合成装置１００とし、光照射して、水（Ｈ２Ｏ）の酸化反応で生成された酸素（Ｏ２）と二酸化炭素（ＣＯ２）の還元反応で生成されたギ酸（ＨＣＯＯＨ）をモニターし、電流−電圧特性を測定した。
<Electrochemical characteristics evaluation>
In this example, the electrochemical characteristics of carbon dioxide (CO 2 ) reduction reaction and water (H 2 O) oxidation reaction were evaluated. The oxidation electrode (anode electrode) 104 and the ruthenium complex polymer (RuCP) -supporting porous carbon reduction electrode (cathode electrode) formed by the above method are opposed to each other, and carbon dioxide (CO 2 ) gas in a phosphate buffer aqueous solution is interposed between the electrodes. Was supplied while bubbling. The phosphate buffer aqueous solution was prepared by mixing K 2 HPO 4 and KH 2 PO 4 at a molar ratio of 1: 1 and using ultrapure water so that the phosphate concentration was 0.1M. The reduction reaction of carbon dioxide (CO 2 ) and the oxidation reaction of water (H 2 O) were controlled in a constant current mode using an electrochemical measurement system (HA-3001A manufactured by Hokuto Denko). At this time, the photosynthesis apparatus 100 in which the reduction electrode 102 and the oxidation electrode 104 are connected via the solar battery cell 108 is used, and the light (O 2 ) generated by the oxidation reaction of water (H 2 O) is irradiated with light. Formic acid (HCOOH) produced by the reduction reaction of carbon dioxide (CO 2 ) was monitored, and current-voltage characteristics were measured.
このとき、可視光波長領域において透光性を有する酸化電極１０４を通してリン酸緩衝水溶液における水（Ｈ２Ｏ）の酸化反応を観察することができた。すなわち、酸化電極１０４を通して水（Ｈ２Ｏ）の酸化反応で生成された酸素（Ｏ２）の泡を明瞭に観察することができた。 At this time, the oxidation reaction of water (H 2 O) in the phosphate buffered aqueous solution could be observed through the oxidation electrode 104 having translucency in the visible light wavelength region. In other words, oxygen (O 2 ) bubbles generated by the oxidation reaction of water (H 2 O) through the oxidation electrode 104 could be clearly observed.
図４は、酸化電極１０４と還元電極（カソード電極）間の電圧をモニターした結果を示す。図４に示すように、２ｍＡ／ｃｍ２及び３ｍＡ／ｃｍ２のいずれの定電流モードにおいても時間的に安定に二酸化炭素（ＣＯ２）還元反応と水（Ｈ２Ｏ）の酸化反応が持続することが確認できた。また、図５に示すように、還元電極１０２と酸化電極１０４とを太陽電池セル１０８を介して接続した光合成装置１００における電流−電圧特性が測定された。 FIG. 4 shows the result of monitoring the voltage between the oxidation electrode 104 and the reduction electrode (cathode electrode). As shown in FIG. 4, the carbon dioxide (CO 2 ) reduction reaction and the water (H 2 O) oxidation reaction continue stably over time in both constant current modes of 2 mA / cm 2 and 3 mA / cm 2. I was able to confirm. Further, as shown in FIG. 5, the current-voltage characteristics were measured in the photosynthetic device 100 in which the reduction electrode 102 and the oxidation electrode 104 were connected via the solar battery cell 108.
また、図６は、二酸化炭素（ＣＯ２）還元反応で生成したギ酸（ＨＣＯＯＨ）をイオンクロマトグラフ（Ｔｈｅｒｍｏ製 ＩＣＳ−２１００）で定量した結果を示す。図６に示すように、ギ酸（ＨＣＯＯＨ）の生成量は時間の経過に伴って線形的に増加した。また、ファラデー効率は、８５％以上８８％以下であった。 FIG. 6 shows the results of quantitative determination of formic acid (HCOOH) produced by carbon dioxide (CO 2 ) reduction reaction by ion chromatography (ICS-2100 manufactured by Thermo). As shown in FIG. 6, the amount of formic acid (HCOOH) produced increased linearly with time. The Faraday efficiency was 85% or more and 88% or less.
＜電極の光学特性評価＞
本実施例における酸化電極１０４及び還元電極１０２の光学特性（直線透過率）を分光エリプソメーター（ＪＡウーラム社製 Ｍ２０００Ｕ）を用いて計測した。図７は、光学特性の測定結果を示す。なお、比較例として、市販のＴｉ基板上に酸化イリジウム（ＩｒＯｘ）をコーティングした酸化電極（Ａｎｏｄｉｃ１００：日進化成）及び市販のＰｔ箔状の触媒電極の光学特性を測定した。なお、図７中において、酸化イリジウム（ＩｒＯｘ）を１回塗布した例を（ＩｒＯｘ ２５ｍｌ×１）と示し、２回塗布した例を（ＩｒＯｘ ２５ｍｌ×２）と示し、３回塗布した例を（ＩｒＯｘ ２５ｍｌ×３）と示した。また、上記還元電極の作製方法２にて作成した還元電極１０２の例を（ナノ粒子Ｐｔ／ＦＴＯ）と示した。また、市販の酸化電極を（Ａｎｏｄｉｃ）と示し、Ｐｔ箔状の電極を（Ｐｔホイル）と示した。
<Evaluation of optical characteristics of electrode>
The optical characteristics (linear transmittance) of the oxidation electrode 104 and the reduction electrode 102 in this example were measured using a spectroscopic ellipsometer (M2000U manufactured by JA Woollam). FIG. 7 shows the measurement results of the optical characteristics. As comparative examples, the optical characteristics of an oxidation electrode (Anodic 100: Nihon Kasei Co., Ltd.) obtained by coating a commercially available Ti substrate with iridium oxide (IrOx) and a commercially available Pt foil-like catalyst electrode were measured. In FIG. 7, an example in which iridium oxide (IrOx) is applied once is shown as (IrOx 25 ml × 1), an example in which it is applied twice (IrOx 25 ml × 2), and an example in which it is applied three times ( IrOx 25 ml × 3). Moreover, the example of the reduction electrode 102 produced by the production method 2 of the reduction electrode is shown as (nanoparticle Pt / FTO). A commercially available oxidation electrode was indicated as (Anodic), and a Pt foil-like electrode was indicated as (Pt foil).
図７に示すように、本実施例における酸化電極１０４及び還元電極の作製方法２にて作成した還元電極１０２の透過率は、いずれも、市販のＴｉ基板上に酸化イリジウム（ＩｒＯｘ）をコーティングした酸化電極（Ａｎｏｄｉｃ１００：日進化成）やＰｔ箔触媒電極よりも高く、視認性に優れていることが判明した。また、具体的には、本実施例の酸化電極１０４及び還元電極の作製方法２にて作成した還元電極１０２は、４００ｎｍ以上７００ｎｍ以下の光の波長領域において入射した光のうち少なくとも２０％以上を透過することが確認できた。 As shown in FIG. 7, the transmittance of the reduction electrode 102 produced by the production method 2 of the oxidation electrode 104 and the reduction electrode in this example were both coated with iridium oxide (IrOx) on a commercially available Ti substrate. It was found to be higher than the oxidation electrode (Anodic 100: Nihon Kasei Co., Ltd.) and the Pt foil catalyst electrode and excellent in visibility. Further, specifically, the oxidation electrode 104 and the reduction electrode 102 produced by the production method 2 of the reduction electrode of the present example can emit at least 20% or more of incident light in the wavelength region of light of 400 nm to 700 nm. It was confirmed that it was transmitted.
以上のように、水（Ｈ２Ｏ）の酸化反応（酸素ガス発生）及び水（Ｈ２Ｏ）の還元反応（水素ガス発生）を外部から目視で確認でき、電気化学セルの内部の反応を管理して、不具合箇所を早期に発見することができる。すなわち、還元電極１０２の還元電位と酸化電極１０４の酸化電位間の電位差に相当する光起電力を太陽電池セル１０８で供給し、太陽電池セル１０８の背面において還元電極１０２及び酸化電極１０４を対向させて配置し、そのどちらか一方を透光性を有する構成とすることで反応を確認し易い光合成装置を提供することができる。 As described above, water oxidation (oxygen gas evolution) of (H 2 O) and reduction (hydrogen gas evolution) of water (H 2 O) can be confirmed visually from the outside, the inside of the reaction of the electrochemical cell It is possible to manage and find a defective part at an early stage. That is, photovoltaic power corresponding to the potential difference between the reduction potential of the reduction electrode 102 and the oxidation potential of the oxidation electrode 104 is supplied by the solar cell 108, and the reduction electrode 102 and the oxidation electrode 104 are opposed to each other on the back surface of the solar cell 108. The photosynthesis apparatus which can confirm reaction easily can be provided by setting it as the structure which has translucency in either one.
１０ 基板、１２ 透明導電層、１４ 集電配線、１４ａ 導電部、１４ｂ 第１シール部、１４ｃ 第２シール部、１６ 還元触媒、２０ 基板、２２ 透明導電層、２４ 集電配線、２４ａ 導電部、２４ｂ 第１シール部、２４ｃ 第２シール部、２６ 酸化触媒、１００ 光合成装置、１０２ 還元電極、１０４ 酸化電極、１０６ 電解液、１０８ 太陽電池セル、１１０ 窓材、１１２ 枠材。
DESCRIPTION OF SYMBOLS 10 Board | substrate, 12 Transparent conductive layer, 14 Current collection wiring, 14a Conductive part, 14b 1st sealing part, 14c 2nd sealing part, 16 Reduction catalyst, 20 Substrate, 22 Transparent conductive layer, 24 Current collection wiring, 24a Conductive part, 24b 1st seal | sticker part, 24c 2nd seal | sticker part, 26 Oxidation catalyst, 100 Photosynthesis apparatus, 102 Reduction electrode, 104 Oxidation electrode, 106 Electrolyte, 108 Solar cell, 110 Window material, 112 Frame material.
Claims (7)
前記酸化電極及び前記還元電極の少なくとも一方が透光性を有し、前記酸化電極と前記還元電極との間に電解液が導入されていることを特徴とする電気化学セル。 An oxidation electrode including a member having an oxidation catalyst function and a reduction electrode including a member having a reduction catalyst function are installed facing each other.
An electrochemical cell, wherein at least one of the oxidation electrode and the reduction electrode has translucency, and an electrolytic solution is introduced between the oxidation electrode and the reduction electrode.
前記酸化電極及び前記還元電極の少なくとも一方の可視光波長領域における透過率が２０％以上であることを特徴とする電気化学セル。 The electrochemical cell according to claim 1,
An electrochemical cell having a transmittance in a visible light wavelength region of at least one of the oxidation electrode and the reduction electrode of 20% or more.
前記酸化電極及び前記還元電極の間にバイアス電圧が印加されていることを特徴とする電気化学セル。 The electrochemical cell according to claim 1 or 2,
An electrochemical cell, wherein a bias voltage is applied between the oxidation electrode and the reduction electrode.
前記酸化電極及び前記還元電極の間に太陽電池が電気的に接続されており、前記太陽電池によって前記バイアス電圧が印加されていることを特徴とする光合成装置。 An electrochemical cell according to claim 3,
A photosynthesis device, wherein a solar cell is electrically connected between the oxidation electrode and the reduction electrode, and the bias voltage is applied by the solar cell.
前記電解液は、リン酸又はホウ酸緩衝水溶液であることを特徴とする光合成装置。 The photosynthesis device according to claim 4,
The photosynthetic apparatus characterized in that the electrolytic solution is a phosphoric acid or boric acid buffer aqueous solution.
前記還元電極は、二酸化炭素（ＣＯ２）に対する還元機能を有し、
前記酸化電極は、水（Ｈ２Ｏ）を酸化して酸素（Ｏ２）を発生させる酸化機能を有することを特徴とする光合成装置。 The photosynthesis device according to claim 4 or 5,
The reduction electrode has a reduction function for carbon dioxide (CO 2 ),
The photosynthesis apparatus, wherein the oxidation electrode has an oxidation function of oxidizing water (H 2 O) to generate oxygen (O 2 ).
前記還元電極は、水（Ｈ２Ｏ）を還元して水素（Ｈ２）を発生させる酸化機能を有し、
前記酸化電極は、水（Ｈ２Ｏ）を酸化して酸素（Ｏ２）を発生させる酸化機能を有することを特徴とする光合成装置。
The photosynthesis device according to claim 4 or 5,
The reduction electrode has an oxidation function of reducing water (H 2 O) to generate hydrogen (H 2 ),
The photosynthesis apparatus, wherein the oxidation electrode has an oxidation function of oxidizing water (H 2 O) to generate oxygen (O 2 ).
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