JP2000160212A - Production of metallic fine particle-titania composite body - Google Patents
Production of metallic fine particle-titania composite bodyInfo
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- JP2000160212A JP2000160212A JP10337713A JP33771398A JP2000160212A JP 2000160212 A JP2000160212 A JP 2000160212A JP 10337713 A JP10337713 A JP 10337713A JP 33771398 A JP33771398 A JP 33771398A JP 2000160212 A JP2000160212 A JP 2000160212A
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- Prior art keywords
- titania
- fine particle
- particles
- metal fine
- aqueous solution
- Prior art date
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- Pigments, Carbon Blacks, Or Wood Stains (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は溶液中での金属微粒
子の製造方法に係り、詳しくは、有機物を保護層に用い
ず、チタニア粒子に金属微粒子を分散させる金属微粒子
−チタニア複合体の製造方法である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing metal fine particles in a solution, and more particularly, to a method for producing a metal fine particle-titania composite in which metal particles are dispersed in titania particles without using an organic substance for a protective layer. It is.
【０００２】[0002]
【従来の技術】金属微粒子は、真空中で蒸発させた金属
を基板に付着させる方法によって代表される気相法、溶
液中で金属イオンを還元剤によって還元する液相法によ
って作製される。しかし、気相法では基板上で金属が凝
集するなどの問題がある。2. Description of the Related Art Fine metal particles are produced by a gas phase method typified by a method in which a metal evaporated in a vacuum is attached to a substrate, or a liquid phase method of reducing metal ions in a solution by a reducing agent. However, the vapor phase method has problems such as aggregation of metals on the substrate.
【０００３】さらに他の方法として、特公平６―９９５
８５号公報に、高分子層を融解後急速固化することによ
り熱力学的に非平衡状態とし、表面に金属層を密着させ
た後、該高分子層を平衡状態になるまで緩和させること
で該金属層を微粒子化する金属そして／あるいはその酸
化物を高分子層内に分散させる方法が開示されている。
しかし、この方法では、微粒子の分散濃度を高めること
が困難であった。As another method, Japanese Patent Publication No. 6-995
No. 85, the polymer layer is melted and rapidly solidified and then thermodynamically brought into a non-equilibrium state.After the metal layer is brought into close contact with the surface, the polymer layer is relaxed until it reaches an equilibrium state. There is disclosed a method of dispersing a metal and / or an oxide thereof that makes the metal layer fine particles in the polymer layer.
However, in this method, it was difficult to increase the dispersion concentration of the fine particles.
【０００４】一方、溶液中で凝集することなく高度に分
散した金属微粒子を製造する場合、従来は金属塩の水溶
液に還元剤及び界面活性ポリマーを加えてコロイド化
し、金属微粒子に保護層を設けて安定化させていた。On the other hand, when producing highly dispersed metal fine particles without agglomeration in a solution, conventionally, a reducing agent and a surface active polymer are added to an aqueous solution of a metal salt to form colloids, and a protective layer is provided on the metal fine particles. Had been stabilized.
【０００５】[0005]
【発明が解決しようとする課題】しかし上記の方法で
は、還元剤が不純物として残存し、また保護層として使
用する界面活性剤やポリマーは、それらを必要としない
用途では無用であるばかりでなく、それらが悪影響を与
えるような用途では使用できない等の問題があった。However, in the above-mentioned method, the reducing agent remains as an impurity, and the surfactant and the polymer used as the protective layer are not only unnecessary in applications not requiring them, There is a problem that they cannot be used in applications in which they have an adverse effect.
【０００６】本発明はこのような問題点を改善するもの
であり、従来の還元剤の代わりに光照射による光還元を
採用し、また金属微粒子の保護層としての界面活性剤や
ポリマーの使用を排し、不純物を含まず、基板上への製
膜など後加工が容易な金属微粒子−チタニア複合体分散
液及びその製造方法を提供するものである。The present invention has been made to solve such problems, and employs photoreduction by light irradiation in place of a conventional reducing agent, and uses a surfactant or a polymer as a protective layer for metal fine particles. An object of the present invention is to provide a metal fine particle-titania composite dispersion liquid which is discharged, contains no impurities, and is easy to perform post-processing such as film formation on a substrate, and a method for producing the same.
【０００７】[0007]
【課題を解決するための手段】すなわち、本願請求項１
記載の発明は、チタニア粒子群に金属微粒子を分散させ
た金属微粒子−チタニア複合体の製造方法において、酸
性水を用いてチタンアルコキシドを加水分解してチタニ
アゾルを作製し、これに金属塩の水溶液を添加し、この
混合溶液に光を照射した後、該混合溶液から上澄み液を
取り出し、この上澄み液に再度光を照射することによる
金属イオンの光還元を利用して金属微粒子をチタニア粒
子群に分散させたことを特徴とする金属微粒子−チタニ
ア複合体の製造方法であって、従来用いられてきた金属
微粒子の保護層としての界面活性剤等のポリマーや、還
元剤等の不純物が関与しない金属微粒子−チタニア複合
体の製造方法である。That is, Claim 1 of the present application.
The described invention is a method for producing a metal fine particle-titania composite in which metal fine particles are dispersed in a titania particle group, in which a titanium alkoxide is hydrolyzed using acidic water to prepare a titania sol, and an aqueous solution of a metal salt is added thereto. After adding, irradiating the mixed solution with light, removing the supernatant from the mixed solution, and dispersing the metal fine particles into the titania particle group by utilizing the photoreduction of metal ions by irradiating the supernatant with the light again. A method for producing a metal fine particle-titania composite, characterized in that a polymer such as a surfactant as a conventionally used protective layer of the metal fine particle or a metal fine particle free from impurities such as a reducing agent is used. -A method for producing a titania composite.
【０００８】本願請求項２記載の発明は、チタンアルコ
キシドがチタンテトラメトキシド、チタンテトラエトキ
シド、チタンテトラプロポキシド、そしてチタンテトラ
ブトキシドから選ばれた少なくとも１種である請求項１
記載の金属微粒子−チタニア複合体の製造方法である。According to a second aspect of the present invention, the titanium alkoxide is at least one selected from titanium tetramethoxide, titanium tetraethoxide, titanium tetrapropoxide, and titanium tetrabutoxide.
It is a manufacturing method of the metal fine particle-titania composite of the description.
【０００９】本願請求項３記載の発明は、金属塩の水溶
液が塩化金酸四水和物の水溶液、硝酸銀の水溶液、塩化
白金酸六水和物の水溶液、そして塩酸を加えた塩化パラ
ジウムの水溶液から選ばれた少なくとも１種である請求
項１または２記載の金属微粒子−チタニア複合体の製造
方法である。The invention according to claim 3 of the present invention is characterized in that an aqueous solution of a metal salt is an aqueous solution of chloroauric acid tetrahydrate, an aqueous solution of silver nitrate, an aqueous solution of chloroplatinic acid hexahydrate, and an aqueous solution of palladium chloride to which hydrochloric acid is added. The method for producing a metal fine particle-titania composite according to claim 1, which is at least one selected from the group consisting of:
【００１０】本願請求項４記載の発明は混合溶液から上
澄み液を得る手段として、遠心分離を用いる請求項１ま
たは２記載の金属微粒子−チタニア複合体の製造方法で
ある。The invention according to claim 4 of the present application is the method for producing a metal fine particle-titania composite according to claim 1 or 2, wherein centrifugation is used as a means for obtaining a supernatant from the mixed solution.
【００１１】本発明におけるチタニア粒子は、単に金属
微粒子を分散させるための保護剤にとどまらず、チタニ
アの本来有する耐熱性を有効に利用した塗料及び着色
剤、さらには高活性の光触媒としての用途をも提供する
ものである。The titania particles used in the present invention are not limited to a protective agent for simply dispersing metal fine particles, but are also used as paints and coloring agents that make effective use of the inherent heat resistance inherent in titania, and as highly active photocatalysts. Is also provided.
【００１２】従来、金属微粒子はそのプラズモン共鳴吸
収に由来する各金属に特有の色を有する塗料及び着色剤
として用いられてきており、異種金属の混合による透過
色調のバリエーションも展開されている。Conventionally, metal fine particles have been used as paints and coloring agents having a color specific to each metal derived from its plasmon resonance absorption, and variations in transmission color tone by mixing different kinds of metals have been developed.
【００１３】また、本発明における金属微粒子−チタニ
ア複合体のもう一方の要素であるチタニアは、光触媒と
して高い活性を有する物質として知られている。半導体
であるチタニアと金属からなるミクロな光電池としての
機能を利用するもので、光照射によって、水の分解、二
酸化炭素や窒素などの空気中の成分の常温、常圧下での
還元、さらには有害物質の無害化などの機能を発現す
る。光吸収効率を高めるためにチタニア、金属ともに微
粒子化された状態で用いられる。また、金属微粒子担持
チタニア粉体は一酸化炭素の酸化等の触媒活性が高いこ
とが報告されている。Further, titania, which is another element of the metal fine particle-titania composite of the present invention, is known as a substance having high activity as a photocatalyst. Utilizes the function as a micro photovoltaic cell composed of semiconductors, titania and metal, and irradiates light to decompose water, reduce components in the air such as carbon dioxide and nitrogen at normal temperature and pressure, and even harm It exhibits functions such as detoxification of substances. Both titania and metal are used in the form of fine particles to increase light absorption efficiency. In addition, it has been reported that titania powder supporting metal fine particles has high catalytic activity such as oxidation of carbon monoxide.
【００１４】[0014]
【発明の実施の形態】次に本発明に係る金属微粒子−チ
タニア複合体の製造方法について具体的に説明する。ま
ず、酸性水を用いてチタンアルコキシドを加水分解して
チタニアゾルを作製する。このチタニアゾルはチタニア
粒子を水、アルコール混合溶媒中に分散させたものであ
り、チタンアルコキシドのアルコール溶液を加水分解す
ることによって得られる。この際、水は硝酸等の酸によ
って酸性に調整される。この酸性とは具体的にはｐＨ＝
３〜６で表される。ここで使用するチタンアルコキシド
は、チタンテトラメトキシド、チタンテトラエトキシ
ド、チタンテトラプロポキシド、チタンテトラブトキシ
ドから選ばれた少なくとも１種であり、このアルコキシ
ドの添加量は特に限定はされないが、チタニアがゲル化
しない程度にチタンアルコキシドをアルコールで希釈す
る必要がある。Next, a method for producing a metal fine particle-titania composite according to the present invention will be specifically described. First, a titanium alkoxide is hydrolyzed using acidic water to prepare a titania sol. This titania sol is obtained by dispersing titania particles in a mixed solvent of water and alcohol, and is obtained by hydrolyzing an alcohol solution of titanium alkoxide. At this time, the water is adjusted to be acidic with an acid such as nitric acid. This acidity is specifically pH =
It is represented by 3-6. The titanium alkoxide used here is at least one selected from titanium tetramethoxide, titanium tetraethoxide, titanium tetrapropoxide, and titanium tetrabutoxide, and the addition amount of the alkoxide is not particularly limited. It is necessary to dilute the titanium alkoxide with alcohol to the extent that it does not gel.
【００１５】次に、作製したチタニアゾルに金属塩の水
溶液を添加し、金、銀、白金、パラジウムから選ばれた
貴金属のイオンを混合する。具体的には、作製するそれ
ぞれの金属微粒子に対応する金属塩の水溶液として、塩
化金酸四水和物の水溶液、硝酸銀の水溶液、塩化白金酸
六水和物の水溶液、塩酸を加えた塩化パラジウムの水溶
液が挙げられる。金属塩の濃度は特に限定はされない
が、１０-3〜１０-4ｍｏｌ／ｍｌ程度である。Next, an aqueous solution of a metal salt is added to the prepared titania sol, and ions of a noble metal selected from gold, silver, platinum and palladium are mixed. Specifically, as an aqueous solution of a metal salt corresponding to each metal fine particle to be produced, an aqueous solution of chloroauric acid tetrahydrate, an aqueous solution of silver nitrate, an aqueous solution of chloroplatinic acid hexahydrate, and palladium chloride to which hydrochloric acid is added Aqueous solution. The concentration of the metal salt is not particularly limited, but is about 10 -3 to 10 -4 mol / ml.
【００１６】得られた混合溶液に白色光を３０〜６０分
照射する。光源は水銀ランプやキセノンランプ等白色光
を輻射するものであればよく、特に限定されるものでは
ない。The obtained mixed solution is irradiated with white light for 30 to 60 minutes. The light source is not particularly limited as long as it emits white light such as a mercury lamp or a xenon lamp.
【００１７】続いて、上記混合溶液を遠心分離装置、濾
過装置等を用いて透明な上澄み液を抽出する。Subsequently, a transparent supernatant is extracted from the mixed solution using a centrifugal separator, a filter, or the like.
【００１８】得られた上澄み液にさらに白色光を３０〜
６０分照射することにより、各金属微粒子の共鳴プラズ
モン吸収に由来する特有の色を有する金属微粒子−チタ
ニア複合体分散液を得る。Further, white light is added to the obtained supernatant liquid for 30 to 30 minutes.
By irradiating for 60 minutes, a metal fine particle-titania composite dispersion having a specific color derived from resonance plasmon absorption of each metal fine particle is obtained.
【００１９】図１は透過型電子顕微鏡観察結果から作成
した該複合体を表す模式図である。金属微粒子２がチタ
ニア粒子３の群によって取囲まれた状態の金属微粒子−
チタニア複合体１が溶媒４中で凝集することなく安定に
存在する。FIG. 1 is a schematic view showing the composite prepared from the results of transmission electron microscope observation. Metal fine particles in a state where metal fine particles 2 are surrounded by a group of titania particles 3-
The titania complex 1 is stably present in the solvent 4 without aggregation.
【００２０】金属微粒子−チタニア複合体の有効な生成
はチタニア粒子の径に依存すると考えられる。このチタ
ニア粒子の径は、チタニアゾル作製時に加える水のｐＨ
に依存し、塩基性条件下では、該複合体が生成すること
なく、肥大化したチタニア粒子及び金属粒子が沈殿物と
して得られる。ここでチタニア粒子の径とは、図１中で
金属微粒子を取囲む該球状体のチタニア粒子群全体の径
を意味する。It is considered that the effective formation of the fine metal particle-titania composite depends on the diameter of the titania particles. The diameter of the titania particles is determined by adjusting the pH of the water to be added when preparing the titania sol.
Under basic conditions, enlarged complex titania particles and metal particles are obtained as precipitates without formation of the complex. Here, the diameter of the titania particles means the diameter of the whole group of the titania particles of the spherical body surrounding the metal fine particles in FIG.
【００２１】また、チタニアゾルと金属イオンの両方を
含んだ水溶液に光照射し、遠心分離装置によって上澄み
液を抽出し、再び光照射する一連の手続きが必要であ
り、チタニアゾルのみを遠心分離装置にかけた後金属イ
オンを追加したり、チタニアゾルのみに光照射した後金
属イオンを追加したり等の手順では金属微粒子−チタニ
ア複合体は有効に生成せず、肥大化したチタニア粒子及
び金属粒子の沈殿物が得られるのみか、あるいは該複合
体が生成してもその経時安定性に問題が見られる。ここ
で有効な生成とは、顕著な沈殿物が観察されず、かつ得
られた液体の色調変化が肉眼で容易に認められる状態に
よって支持される。Further, a series of procedures for irradiating the aqueous solution containing both the titania sol and the metal ions with light, extracting the supernatant by a centrifugal separator, and irradiating the light again is necessary. Only the titania sol was applied to the centrifugal separator. In the procedure of adding metal ions after, or adding metal ions after irradiating only the titania sol, etc., the metal fine particle-titania complex is not effectively generated, and the enlarged titania particles and precipitates of the metal particles are formed. It is only obtained or, even if the complex is formed, there is a problem in its stability over time. Here, the effective formation is supported by a state in which no remarkable precipitate is observed and a change in the color tone of the obtained liquid is easily recognized by the naked eye.
【００２２】得られた金属微粒子−チタニア複合体は、
得られた金属微粒子−チタニア複合体の構造を調べるた
め、該複合体分散液から、透過型電子顕微鏡及びＸ線回
折用の試料を作製し、それぞれの観察を行った。また元
素分析によって、複合体としての金属微粒子とチタニア
の定量を行った。The obtained metal fine particle-titania composite is
In order to examine the structure of the obtained metal fine particle-titania composite, a sample for transmission electron microscope and X-ray diffraction was prepared from the composite dispersion, and each sample was observed. Further, the metal fine particles and the titania as a composite were quantified by elemental analysis.
【００２３】[0023]
【実施例】次に本発明を具体的な実施例により更に詳細
に説明する。 （チタニアゾルの作製）表１に示すように、チタンアル
コキシドとして採用したチタンテトラプロポキシドのエ
タノール溶液をｐＨをそれぞれ３、６、１０に調整した
水で加水分解することにより、チタニアゾル、Ａ、Ｂ及
びＣを作製した。Now, the present invention will be described in further detail with reference to specific examples. (Preparation of Titania Sol) As shown in Table 1, an ethanol solution of titanium tetrapropoxide employed as a titanium alkoxide was hydrolyzed with water whose pH was adjusted to 3, 6, and 10 to obtain titania sol, A, B and C was prepared.
【００２４】[0024]
【表１】 [Table 1]
【００２５】実施例１ チタニアゾル作製時の水をｐＨ＝３に調整し、金濃度が
１．２×１０-5ｍｏｌ／ｍｌの塩化金酸水溶液及び水を
混合した。得られた水溶液に水銀ランプを０．５時間照
射した。これを遠心分離装置にかけ、得られた淡黄色透
明の上澄み液にさらに水銀ランプを０．５時間照射する
ことによって赤色透明の液体を得た。この液体は経時的
に安定であり、経時により沈殿物が生成することはなか
った。Example 1 Water at the time of preparing a titania sol was adjusted to pH = 3, and an aqueous solution of chloroauric acid having a gold concentration of 1.2 × 10 −5 mol / ml and water were mixed. The obtained aqueous solution was irradiated with a mercury lamp for 0.5 hour. This was centrifuged, and the obtained pale yellow transparent supernatant was further irradiated with a mercury lamp for 0.5 hour to obtain a red transparent liquid. This liquid was stable over time, and no precipitate was formed over time.
【００２６】実施例２ チタニアゾル作製時の水をｐＨ＝６に調整し、実施例１
と同様の手順に従って得た淡黄色透明の上澄み液に水銀
ランプを照射し、同じく赤色透明の液体を得た。この液
体は経時的に安定であり、経時により沈殿物が生成する
ことはなかった。実施例１及び２で得られたこの赤色は
金微粒子のプラズモン共鳴吸収に由来する色であり、つ
まり本発明においては、金微粒子−チタニア複合体の安
定な分散液生成を意味する。具体的には、透過電子顕微
鏡観察の結果より、連なったチタニア粒子によって保護
された金微粒子の実態が明らかになった。得られた金微
粒子の平均粒子径は２０ｎｍ、金微粒子を取り囲むチタ
ニア粒子は１０ｎｍ以下のチタニア粒子が連なったも
の、さらに詳細には透過型電子顕微鏡観察ではチタニア
粒子の金微粒子に接する部分ではアナターゼと思われる
格子が観察された。チタニア粒子によって、金微粒子が
分散媒中で凝集することなく高度に分散した状態で安定
に存在する。またＸ線回折の結果から、チタニア粒子の
構造はアモルファスであることが分かった。Example 2 The water at the time of preparing the titania sol was adjusted to pH = 6, and
The pale yellow transparent supernatant obtained according to the same procedure as described above was irradiated with a mercury lamp to obtain a red transparent liquid. This liquid was stable over time, and no precipitate was formed over time. The red color obtained in Examples 1 and 2 is a color derived from the plasmon resonance absorption of the fine gold particles, that is, in the present invention, means the generation of a stable dispersion of the fine gold particle-titania complex. Specifically, transmission electron microscope observation revealed the actual state of the gold fine particles protected by the continuous titania particles. The average particle diameter of the obtained gold fine particles is 20 nm, and the titania particles surrounding the gold fine particles are a series of titania particles of 10 nm or less. A possible lattice was observed. By the titania particles, the gold fine particles are stably present in a highly dispersed state without aggregating in the dispersion medium. The result of X-ray diffraction showed that the structure of the titania particles was amorphous.
【００２７】比較例１−１ チタニアゾル作製時の水をｐＨ＝１０に調整し、実施例
１と同様の手順に従って得た淡黄色透明の上澄み液に水
銀ランプを照射した。しかし、赤色の液体は得られず、
沈殿物が観察された。Comparative Example 1-1 The water at the time of preparing the titania sol was adjusted to pH = 10, and the light yellow transparent supernatant obtained according to the same procedure as in Example 1 was irradiated with a mercury lamp. However, a red liquid was not obtained,
A precipitate was observed.
【００２８】比較例１−２ チタニアゾルを用いず、塩化金酸水溶液にエタノール及
び水のみを混合した系である。実施例１と同様の手順に
従って得た淡黄色透明の上澄み液に水銀ランプを照射し
た。比較例１と同様、この場合も赤色透明の液体は得ら
れず、沈殿物が観察された。実施例１〜２及び比較例１
の結果を表２に示す。Comparative Example 1-2 This is a system in which only ethanol and water are mixed in a chloroauric acid aqueous solution without using a titania sol. The pale yellow transparent supernatant obtained according to the same procedure as in Example 1 was irradiated with a mercury lamp. As in Comparative Example 1, no red transparent liquid was obtained in this case, and a precipitate was observed. Examples 1 and 2 and Comparative Example 1
Table 2 shows the results.
【００２９】[0029]
【表２】 [Table 2]
【００３０】以上の結果より、チタンアルコキシドを加
水分解する際の水のｐＨによって、生成するチタニアゾ
ルの粒子径が変化し、それが金微粒子−チタニア複合体
の生成に影響を与えたものと考えられる。ｐＨ＝１０で
ある比較例１−１では、金微粒子−チタニア複合体の生
成は困難であり、得られた沈殿物は、肥大化した金粒子
及びチタニア粒子の単なる混合物であると考えられる。
すなわち、チタンアルコキシドを加水分解する水は酸
性、より詳しくはｐＨ＝３〜６で表される酸性である必
要がある。チタニアゾルを含まない比較例１−２におい
ては、金微粒子−チタニア複合体が生成しないことは言
うまでもない。From the above results, it is considered that the particle size of the generated titania sol was changed by the pH of the water at the time of hydrolyzing the titanium alkoxide, which affected the formation of the gold fine particle-titania composite. . In Comparative Example 1-1 in which the pH is 10, it is difficult to form a gold fine particle-titania complex, and the obtained precipitate is considered to be a mere mixture of enlarged gold particles and titania particles.
That is, the water for hydrolyzing the titanium alkoxide needs to be acidic, more specifically, acidic as represented by pH = 3-6. It goes without saying that, in Comparative Example 1-2 containing no titania sol, no gold fine particle-titania composite was formed.
【００３１】比較例２ 以上の実施例及び比較例においては、チタニアゾル及び
塩化金酸の水溶液への最初の水銀ランプの照射によっ
て、比較的大きな粒子径のチタニア粒子が関与した金微
粒子−チタニア複合体に由来すると考えられる紫色の沈
殿物が得られた。そこで、金微粒子−チタニア複合体を
生成するに好適な粒子径のチタニア粒子のみを抽出する
目的で、チタンテトラプロポキシドの加水分解によって
得られたチタニアゾルのみを遠心分離装置にかけ、得ら
れたチタニアゾルに塩化金酸水溶液を混合し、その水溶
液に水銀ランプを照射した。チタニアゾル作製時の水の
ｐＨは比較例２−１〜２−３において、それぞれ３、
６、１０に調整した。結果を表３に示す。COMPARATIVE EXAMPLE 2 In the above Examples and Comparative Examples, the first irradiation of the aqueous solution of titania sol and chloroauric acid with a mercury lamp resulted in a gold fine particle-titania composite involving titania particles having a relatively large particle diameter. The resulting precipitate was a purple precipitate believed to be derived from. Therefore, for the purpose of extracting only titania particles having a particle diameter suitable for producing a gold fine particle-titania composite, only a titania sol obtained by hydrolysis of titanium tetrapropoxide is subjected to a centrifugal separator, and the obtained titania sol is added to the obtained titania sol. An aqueous solution of chloroauric acid was mixed, and the aqueous solution was irradiated with a mercury lamp. The pH of water at the time of preparing the titania sol was 3, in Comparative Examples 2-1 to 2-3, respectively.
Adjusted to 6, 10. Table 3 shows the results.
【００３２】[0032]
【表３】 [Table 3]
【００３３】表３中に示された塩化金酸水溶液の量は、
各比較例において、金微粒子−チタニア複合体が生成す
るに好適な量、すなわち肥大化した金粒子が沈殿物とし
て生成しない最大の量を示す。チタニアゾル作製時の水
のｐＨ＝３である比較例２−１において、最も有効に金
微粒子−チタニア複合体が生成することがわかり、ここ
でもチタニアゾル作製時の水のｐＨのチタニアゾルの粒
子径への影響が明らかになった。The amount of the chloroauric acid aqueous solution shown in Table 3 is as follows:
In each of the comparative examples, an amount suitable for forming the gold fine particle-titania complex, that is, a maximum amount at which the enlarged gold particles do not form as a precipitate is shown. In Comparative Example 2-1 in which the pH of water at the time of producing a titania sol was 3, it was found that a gold fine particle-titania complex was most effectively formed. Here, the pH of water at the time of producing the titania sol was reduced to the particle size of the titania sol. The effects have become apparent.
【００３４】ただし、上記比較例２においては、比較例
１と同様の紫色の沈殿物が生成し、得られた金微粒子−
チタニア複合体の経時安定性に問題が見られた。However, in Comparative Example 2, the same purple precipitate as in Comparative Example 1 was formed, and
There was a problem with the stability over time of the titania composite.
【００３５】比較例３ 以上の比較例において、光照射によってチタニア粒子が
沈殿する現象が観察されたため、チタンテトラプロポキ
シドの加水分解によって得られたチタニアゾルのみに水
銀ランプを照射した。得られた溶液を遠心分離装置にか
け、上澄み液を抽出し、続いて塩化金酸水溶液を混合
し、再び水銀ランプを照射した。チタニアゾル作製時の
水のｐＨは比較例３−１〜３−３において、それぞれ
３、６、１０に調整した。結果を表４に示す。Comparative Example 3 In the above Comparative Example, a phenomenon that titania particles were precipitated by light irradiation was observed. Therefore, only a titania sol obtained by hydrolysis of titanium tetrapropoxide was irradiated with a mercury lamp. The obtained solution was centrifuged, the supernatant was extracted, and subsequently a chloroauric acid aqueous solution was mixed, and the mixture was irradiated with a mercury lamp again. The pH of water at the time of preparing the titania sol was adjusted to 3, 6, and 10 in Comparative Examples 3-1 to 3-3, respectively. Table 4 shows the results.
【００３６】[0036]
【表４】 [Table 4]
【００３７】比較例３−１〜３−３のいずれにおいて
も、金微粒子−チタニア複合体に由来する赤色の液体は
得られず、金の沈殿物が得られた。ここでは、金微粒子
−チタニア複合体の生成に好適なチタニア粒子が遠心分
離処理により大部分除去されたものと考えられる。した
がって、好適なチタニア粒子が除去されないためには、
金イオンの存在が必要であると思われる。すなわち、最
初の光照射により金イオンとチタニア粒子間で何らかの
相互作用が働いていると考えられる。In each of Comparative Examples 3-1 to 3-3, a red liquid derived from the fine gold particle-titania composite was not obtained, and a gold precipitate was obtained. Here, it is considered that titania particles suitable for the production of the gold fine particle-titania composite were mostly removed by centrifugation. Therefore, in order for suitable titania particles not to be removed,
It appears that the presence of gold ions is necessary. That is, it is considered that some interaction between the gold ions and the titania particles is working by the first light irradiation.
【００３８】[0038]
【発明の効果】以上説明したように、本願各請求項記載
の発明は、チタニア粒子群に金属微粒子を分散させた金
属微粒子−チタニア複合体の製造方法において、酸性水
を用いてチタンアルコキシドを加水分解してチタニアゾ
ルを作製し、これに金属塩の水溶液を添加し、この混合
溶液に光を照射した後、該混合溶液から上澄み液を取り
出し、この上澄み液に再度光を照射することによる金属
イオンの光還元を利用して金属微粒子をチタニア粒子群
に分散させた金属微粒子−チタニア複合体の製造方法で
あって、光還元を採用することにより、不純物として残
存する還元剤が不要となる。また、金属微粒子の活性を
阻害するような保護層としての界面活性剤やポリマーも
関与しないことから、活性度が高い触媒作用も期待でき
る。また、チタニア粒子の耐熱性を活かした金属微粒子
からなる着色剤としての用途をも提供するものである。As described above, the invention described in each claim of the present application provides a method for manufacturing a metal fine particle-titania composite in which metal fine particles are dispersed in titania particles, in which titanium alkoxide is hydrolyzed using acidic water. After decomposing to produce a titania sol, an aqueous solution of a metal salt is added thereto, and the mixed solution is irradiated with light, then the supernatant is taken out from the mixed solution, and the metal ion is obtained by irradiating the supernatant with light again. The method for producing a metal fine particle-titania composite in which metal fine particles are dispersed in a titania particle group using the photoreduction of (1). By employing photoreduction, a reducing agent remaining as an impurity becomes unnecessary. In addition, since a surfactant or a polymer as a protective layer that inhibits the activity of the metal fine particles is not involved, a catalytic activity having high activity can be expected. Further, the present invention also provides a use as a colorant composed of fine metal particles utilizing the heat resistance of titania particles.
【図１】金属微粒子−チタニア複合体の模式図を示す。FIG. 1 is a schematic view of a metal fine particle-titania composite.
１ 金属微粒子−チタニア複合体 ２ 金属微粒子 ３ チタニア粒子 ４ 溶媒 DESCRIPTION OF SYMBOLS 1 Metal fine particle-titania composite 2 Metal fine particle 3 Titania particle 4 Solvent
フロントページの続き Ｆターム(参考） 4G047 CA02 CA05 CB06 CC01 CC03 CD03 4J037 AA22 CA05 CA14 CA15 CB05 DD20 EE08 EE19 EE28 EE33 EE43 4K017 AA08 BA02 CA07 DA07 DA09 EJ01 FB11 Continued on the front page F term (reference) 4G047 CA02 CA05 CB06 CC01 CC03 CD03 4J037 AA22 CA05 CA14 CA15 CB05 DD20 EE08 EE19 EE28 EE33 EE43 4K017 AA08 BA02 CA07 DA07 DA09 EJ01 FB11
Claims (4)
金属微粒子−チタニア複合体の製造方法において、酸性
水を用いてチタンアルコキシドを加水分解してチタニア
ゾルを作製し、これに金属塩の水溶液を添加し、この混
合溶液に光を照射した後、該混合溶液から上澄み液を取
り出し、この上澄み液に再度光を照射することによる金
属イオンの光還元を利用して金属微粒子をチタニア粒子
群に分散させたことを特徴とする金属微粒子−チタニア
複合体の製造方法。In a method for producing a metal fine particle-titania composite in which metal fine particles are dispersed in titania particles, a titanium alkoxide is hydrolyzed using acidic water to prepare a titania sol, and an aqueous solution of a metal salt is added thereto. After adding, irradiating the mixed solution with light, removing the supernatant from the mixed solution, and dispersing the metal fine particles into the titania particle group by utilizing the photoreduction of metal ions by irradiating the supernatant with the light again. A method for producing a metal fine particle-titania composite, comprising:
シド、チタンテトラエトキシド、チタンテトラプロポキ
シド、そしてチタンテトラブトキシドから選ばれた少な
くとも１種である請求項１記載の金属微粒子−チタニア
複合体の製造方法。2. The method for producing a metal fine particle-titania composite according to claim 1, wherein the titanium alkoxide is at least one selected from titanium tetramethoxide, titanium tetraethoxide, titanium tetrapropoxide, and titanium tetrabutoxide. .
液、硝酸銀の水溶液、塩化白金酸六水和物の水溶液、そ
して塩酸を加えた塩化パラジウムの水溶液から選ばれた
少なくとも１種である請求項１または２記載の金属微粒
子−チタニア複合体の製造方法。3. The aqueous solution of a metal salt is at least one selected from an aqueous solution of chloroauric acid tetrahydrate, an aqueous solution of silver nitrate, an aqueous solution of chloroplatinic acid hexahydrate, and an aqueous solution of palladium chloride to which hydrochloric acid is added. The method for producing a metal fine particle-titania composite according to claim 1 or 2, wherein
遠心分離を用いる請求項１または２記載の金属微粒子−
チタニア複合体の製造方法。4. A means for obtaining a supernatant from a mixed solution,
The metal fine particles according to claim 1 or 2, wherein centrifugation is used.
A method for producing a titania composite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10337713A JP2000160212A (en) | 1998-11-27 | 1998-11-27 | Production of metallic fine particle-titania composite body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10337713A JP2000160212A (en) | 1998-11-27 | 1998-11-27 | Production of metallic fine particle-titania composite body |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000160212A true JP2000160212A (en) | 2000-06-13 |
Family
ID=18311274
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10337713A Pending JP2000160212A (en) | 1998-11-27 | 1998-11-27 | Production of metallic fine particle-titania composite body |
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| Country | Link |
|---|---|
| JP (1) | JP2000160212A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001077233A1 (en) * | 2000-04-06 | 2001-10-18 | Kabushiki Kaisha Toshiba | Oxide composite particle and method for its production, phosphor and method for its production, color filter and method for its manufacture, and color display |
| JP2006051431A (en) * | 2004-08-11 | 2006-02-23 | Mitsui Mining & Smelting Co Ltd | Ternary catalyst for exhaust gas purification, and its production method |
| JP2006152327A (en) * | 2004-11-25 | 2006-06-15 | Dowa Mining Co Ltd | Silver powder and production method therefor |
| JP2007216197A (en) * | 2006-02-20 | 2007-08-30 | Univ Kinki | Photocatalytic film, photocatalytic material and methods for manufacturing them |
| CN110860298A (en) * | 2019-11-29 | 2020-03-06 | 南开大学 | Metallic/multifaceted Cu2O composite adjustable and controllable photocatalyst and preparation method thereof |
-
1998
- 1998-11-27 JP JP10337713A patent/JP2000160212A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001077233A1 (en) * | 2000-04-06 | 2001-10-18 | Kabushiki Kaisha Toshiba | Oxide composite particle and method for its production, phosphor and method for its production, color filter and method for its manufacture, and color display |
| US6946785B2 (en) | 2000-04-06 | 2005-09-20 | Kabushiki Kaisha Toshiba | Oxide composite particle and method for its production, phosphor and method for its production, color filter and method for its manufacture, and color display |
| JP2006051431A (en) * | 2004-08-11 | 2006-02-23 | Mitsui Mining & Smelting Co Ltd | Ternary catalyst for exhaust gas purification, and its production method |
| JP2006152327A (en) * | 2004-11-25 | 2006-06-15 | Dowa Mining Co Ltd | Silver powder and production method therefor |
| JP2007216197A (en) * | 2006-02-20 | 2007-08-30 | Univ Kinki | Photocatalytic film, photocatalytic material and methods for manufacturing them |
| CN110860298A (en) * | 2019-11-29 | 2020-03-06 | 南开大学 | Metallic/multifaceted Cu2O composite adjustable and controllable photocatalyst and preparation method thereof |
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