JPS58183940A - Photochemical reaction using solar rays - Google Patents

Abstract

PURPOSE:To enhance the reaction efficiency of a reaction system, by irradiating solar rays to the reaction system containing reactant components and a photocatalyst in such a state that a coloring matter having special capacity is added to said reaction system to availably utilize light energy of solar rays. CONSTITUTION:In a method wherein solar rays are irradiated to a reaction system containing reactant components and a photocatalyst to carry out photochemical reaction, a coloring matter wherein the position of a light absorbing band is shifted to a high energy side form the position of the light absorbing band of the photocatalyst and the position of a light emitting band is same or near to the position of the light absorbing band of the photocatalyst is further added to said reaction system. As the coloring matter, for example, a combination of trisruthenium pyridyl complex [Ru(bpy)<2+>3] and 7-diethylamino-4-methyl cumarine (DAMC) is used. As the result, because the light energy of solar rays capable of being not utilized conventionally can be utilized in photochemical reaction, the reaction efficiency of the reaction system is enhanced.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a nine-light chemical reaction method using sunlight.

More specifically, the present invention relates to a photochemical reaction method that efficiently utilizes sunlight energy.

[Technical background of the invention and electric point between them]

The photochemical reaction method, which converts the original energy of sunlight into chemical energy using a photocatalyst and performs a chemical reaction, has been attracting attention in recent years as a new energy source utilization system.

For example, a photochemical reaction is known in which a reaction system in which water and a photocatalyst coexist is irradiated with sunlight to cause photolysis of water as shown by the following formula [Chemistry, l4m), No. 1m] ,989ha,(19
1979)].

As photocatalysts used for such reactions, 'rto1゜8rT10g + laTiom @l1m, Wo
Oxide conductors such as ruthenium bipyridyl complexes such as ruthenium bipyridyl complexes, and metal complexes such as ruthenium ruphyrin O metal complexes are known.

On the other hand, as is clear from the energy distribution 11 shown in FIG. 1, the sunlight generated by the reaction system KlI# is distributed over an extremely wide wavelength range centered on the visible range. 9. As illustrated in Figure 2, photocatalysts have a light absorption band in a relatively narrow energy range centered around a single wavelength range, so they can be used in photochemical reactions such as those described above. This means that it absorbs only the light energy of sunlight that falls within the wavelength range of the light absorption band and converts it into chemical energy.

Therefore, in conventional photochemical reactions, only a small portion of the light energy of the irradiated sunlight is effectively utilized, so the problem that the photochemical reaction efficiency becomes rather low cannot be avoided.

[Purpose of the invention]

An object of the present invention is to provide a photochemical reaction method that effectively utilizes the optical energy of sunlight and thereby improves the reaction efficiency of a reaction system.

[Summary of the invention]

The invention is a method of irradiating a reaction system containing a reaction component and a photocatalyst with sunlight to carry out a photochemical reaction, and in which the reaction system is exposed to a light-absorbing monster whose position is a line photocatalyst. Attack on the higher energy side than the position.

In addition, it is characterized in that a dye whose emission band is at the same position or linearly similar to the position of the photocatalyst is further added and irradiated with sunlight.

The main feature of the method of the present invention is that the dye having the above-mentioned characteristics is added to the reaction system and the reaction system is irradiated with sunlight.

As illustrated in No. 311i1, the K-shape pigment of the present invention has a light absorption band on the high energy side (smoke wavelength region side) of the light absorption band of the nine-part catalyst shown in FIG. Absorption strength [1
), and the emission band is located on the low energy side (long line length side) with a loud Stokes shift, and it is at the same position as the scissors party attack O party lk interpretation, or at a very close position ([Fig. 3 It is a dye whose emission intensity is 2).

When such a dye coexists with a photocatalyst in the reaction system, after being irradiated with sunlight, the photocatalyst first absorbs energy in the nine wavelength range shown in Figure 2. One dye at the same time is msgo
The absorption intensity is expressed as 1, and the long range Q light energy is collected as 1.
1:1 wave with luminous intensity 2 and the Great Wall (No. Z@
(D @ long range and red 1 are the same) light energy is emitted.

Therefore, in addition to the light energy shown in Figure 2, the photocatalyst generates
t which absorbs as much as 20 optical energies can be generated at the intensity of the light emission shown in Figure #I3.

In this way, the dye itself is simply a conversion medium that Stokes-shifts the light energy of sunlight toward longer wavelengths, and does not directly participate in the chemical reaction. Dye sensitization method in photoelectrode reaction known from [Science, Vol. 47, No. 11, p. 679,
(1977)] has completely different effects.

Due to the presence of the dye according to the present invention, the photocatalyst in one reaction system can collect 4 hectares of the light energy of sunlight, which could not be converted conventionally, and therefore the reaction efficiency of the reaction system is improved.

Such a dye is selected depending on the photocatalyst used in one reaction system.

For example, the photocatalyst used in the photolysis reaction of water, trisruthenium bilysyl anchor (mu(bpy)''), is shown in Figure 4 and has a beak as shown in the nine absorption spectra.
It has a strong optical absorption band around a wavelength of 450 nm.

At around a wavelength of 400 nm, the optical absorption decreases.

On the other hand, 7-diethylamino-4-metelquorin (DAMC) is a type of coumarin group pigment.

As shown in FIG.
X 1 ()') and liquid length 4! It has a relatively strong emission band (fluorescence) 2 with a maximum value near ionm.

Therefore, if sunlight is irradiated onto water where both of them coexist, SRm (bPF) is difficult to be collected by itself and DAMC absorbs the light energy near wavelength 35 Omwa and undergoes a Stokes shift. Since light energy with a liquid length of around 4B6 am is emitted, the light energy of Ru(bpy)" can also be collected, improving the overall reaction efficiency.

In this way, a certain dye corresponds to a photocatalyst. As for such a table assembly, the above-mentioned 9Ru(bP)'
)” -DAMC (In addition to D, combinations such as iron phthalocyanine-7$ fluorescein sodium and fro7trone-4-methylumperifene can be mentioned.

[Example of invention]

Example 1 Water was photolyzed using an aqueous solution 100- containing the following components as a reaction system.

Ru(bPF) a g S X 1 G” as a photocatalyst
″”mol/l.

DAMC as color chart: 5 x 10'''''Otori/I/I
In addition, the following components are included as auxiliary systems for photolysis reactions. Ruthenium dioxide Ru01 as an oxidation catalyst
Less than 2X10-'mol/1. Methylbiotxfn (MV) as a reducing electron carrier! 2.5 X 1 G-
” mol/1. Platinum (Pt) as reduction catalyst: 1g
Ido! This reaction system was irradiated with sunlight for t-3 hours (from $11:00 p.m. to 2:00 p.m.) at 1.5×1 G″″’mol/ja. The average irradiation intensity was 80 mW/cd.

In this system, the following photochemical reaction proceeds and hydrogen is generated.

The amount of hydrogen generated was 12 smol.

For comparison, in a system without DAMC, the amount of O hydrogen generated was 0.7 μml under the same conditions.

Therefore, the method of the present invention has a reaction efficiency of 1
The iP was improved by 1.7 times.

Example 2 Photolysis of water was carried out using an aqueous solution ls〇- containing each of the following components as a reaction system.

As a photocatalyst, one mouthful of 7 Rabin (PF): 2 X 1 G''
″6 mol/l, 4-methykflemperi7 as a dye
Elono (4MU) was used at a concentration of 2×10″·mol/jt. In addition, p y o @ collection (Tuttle is shown in Figure 6, 4MU
The absorption and emission spectra of the compound are shown in Fig. 7, 1.2, respectively. In addition, platinum colloid is used as a reaction O support system! 5WI
g% ethylenecyanetetraacetic acid (EDTM); 1 x 10-
“Good to add m@I/I.

This reaction system was exposed to sunlight for t3 hours (from 11:00 a.m. to 2:00 p.m.).
irradiated. The average irradiation intensity is 80rnW/-.

In this system, hydrogen is generated due to the EDTAO conversion reaction and water reduction reaction.

The amount of hydrogen generated is 110^moj.

Rounding off the comparison, let's look at the system without adding 4MUt.

The amount of hydrogen generated under the same conditions was 80 μgaml.

Therefore, the method of the present invention improves the O reaction efficiency by 1.4 times compared to the conventional method.

〔Effect of the invention〕

As is clear from the above explanation, the present invention method company.

The light energy of whole sunlight, which could not be used conventionally, can also be used for photochemical reactions, improving the reaction efficiency of the reaction system. In addition to the production of hydrogen through photolysis of water, it can also be applied to various energy conversion reactions using light, such as fuel synthesis from biomass and fuel synthesis using solid bases of carbon dioxide.
), furthermore, it suggests that it can be applied to photochemical synthesis using chemical substances in the form of am, and its industrial value is great.

[Brief explanation of drawings]

Figure 1 shows the energy distribution of sunlight, 1Illt2WJ shows an example of the light absorption band tube of a photocatalyst, and Figure 3 shows an example of the absorption intensity IIIL1 and emission intensity 2 of the dye according to the present invention. 4 #AId Ru ('bp
y) Absorption spectrum of @+, JIIs diagram Absorption spectrum l of UDAMC and emission spectrum 1m16 diagram is PFC
) Absorption vector (Fig. 7 is 4 MUC) collection spectrum 1 and emission vector 3. Figure 1 Figure 2 200 600 1000 1400 18003
L table (nm) - Figure 3 C8m) - Figure 4 L (nm) - 200300400500600 3L table +nm1-- Figure 6 1 length - Tnm) -→ Figure 7

Claims (1)

[Claims] A method for causing a photochemical reaction to occur by irradiating sunlight onto a reaction system containing a reaction component and a photocatalyst. The reaction system k. The position of the light absorption band is on the higher energy side than the position of the photocatalyst, or the position of the emission band is the same as or close to the position of the light absorption band 0 of the photocatalyst. A nine-light chemical reaction method using sunlight, which is characterized by further adding a pigment.