SI24129A - The process for preparation thin film of Pt catalyst at low temperatures - Google Patents

Abstract

The present invention relates to a novel process for the preparation of thin layer of catalytic active platinum at low temperatures using gaseous phase reducing agents, on a catalytic active platinum application to glass, ceramic and polymer substrates, and on carbon, semiconductor materials and other metal oxides. The new process solves the problem of applying a layer of elementary platinum at low temperature, which allows the application of thermally unstable substrates. A platinum prepared in this way can be used as an immobilized catalyst and as an electro catalyst for Graetz's solar cells, fuel cells and electro-oxidation / reduction of organic compounds when Pt is applied to an electrically conductive substrate.

Description

The process of preparing a thin layer of Pt catalyst at low temperatures

FIELD OF THE INVENTION

The present invention relates to a new process for the preparation of thin films of catalytically active platinum - hereinafter Pt - at low temperature with a gas phase reducing agent.

A technical problem

Gratzle-type solar cells (DSSC) are potential candidates for next-generation solar cells because they are considered to be more affordable due to lower cost of materials used and rapid production; see B. O'Regan, M.Gratzel, Nature 353 (1991) 737-740; T.N.Murakami, M.Gratzel, Inorg.Chim.Acta 361 (2008) 572-580). One of the essential parts of this cell is the counter electrode, which collects electrons from the outer circuit and catalyzes the redox regeneration of the electrolyte. A typical counter electrode is made by applying a catalyst layer to a glass plate covered with a conductive layer.

Different materials have been tested so far in the manufacture of the counter electrode, with platinum application being the most effective. When manufacturing a Pt-counter electrode on a glass plate, platinum must be activated at temperatures above 400 ° C.

Flexible DSSC cells in which the electrodes are applied to polymeric materials are an attractive development direction. Advantages of using polymeric materials are further reduction of production costs and greater flexibility of use. One of the major problems of making flexible DSSC cells is the preparation of a Pt-counter electrode on a polymer film. The problem lies not only in the application of the catalyst to the polymers, but especially in the low temperature of preparation and activation of the catalyst, which, due to the limited thermal stability of certain polymer substrates, may not exceed a certain temperature. Also, for better performance, the Pt catalyst must have a large specific surface area and, due to the Pt price, the amount of use should be kept to a minimum.

For all these reasons, there is a need for an improved process for producing a counter electrode on a polymer film at low temperatures so that the platinum layer is very thin, while having a sufficiently large surface area and catalytic efficiency and good adhesion to the substrate.

The present invention satisfies this need, since the object of the invention is a novel method of preparing a low temperature platinum catalyst layer with extreme adhesion, particle size of less than 50 nm, uniform coverage of the substrate surface, and catalytic activity comparable to a high temperature Pt catalyst.

The state of the art

Elemental platinum has excellent catalytic properties and has long been used in various branches of the art. Several catalyst preparation methods are known, such as: sol-gel synthesis, electrodeposition, electroless deposition, hydrothermal and solvothermal methods, and various physical techniques such as sputtering and laser ablation; see Aicheng Chen, Peter Holt-Hindle, Chem. Rev. 110 (2010) 3767-3804).

Chemical methods are characterized by the fact that the preparation process is carried out in two stages. The first stage is the reduction of the starting compound to elemental platinum, and the second is the activation of platinum at temperatures generally higher than 400 ° C. One of the two phases is also usually associated with the deposition of a catalytic layer on a solid substrate.

The need for low-temperature platinum deposition emerged with the start of the development of a flexible Gratzel solar cell. One of the first flexible counter electrodes was fabricated at room temperature by mechanically applying a semiconductor powder of Sb: SnO ₂ enriched with Pt onto a PET film; see H.Lindstrom et al., Nano Lett., 1 (2001) 97-100). The authors report that the overall schoolchild to electric conversion efficiencies of nanostructured films thus prepared is up to 4.9%. This type of counter electrode is dark colored and therefore not suitable for inverted solar cells where sunlight enters through the counter electrode.

-3When producing Gratzl solar cells with a photoanode on titanium foil, the counter electrode was prepared by electrochemical deposition of platinum on ITO / polyethylene naphthalate (ITO / PEN); see S.lto et al., Chem.

Commun. 38 (2006) 4004-4006.

The thin films prepared from the solutions by the above methods generally do not achieve the quality of the films prepared at higher temperatures, therefore, the sequential ion adsorption and reaction method described in Successive Lonic Layer Adsorption and Reaction, ŠILAR, S.Lindroos, M.Leskela, Solution Inorganic Materials Processing, edited by DBMitzi, John Wiley & Sons, Inc. 2009, 239-282. In the ŠILAR method, the substrate is immersed immersed in the cationic and anionic precursors, while the substrate is thoroughly washed in a pure solvent, usually in water. Thin films grow layer by layer through repetition of said cycles. After the application is complete, the batch of layers is usually still thermally treated, depending on the nature of the layer and the intended use. The SILAR method is suitable for layers formed by the reaction between a cation and an anion, e.g. ZnS, but elemental platinum formation does not proceed by this mechanism.

Faster precursor deposition on the substrate was achieved by the Ion Layer Gas Reaction method described in Ion Layer Gas Reaction, ILGAR, S.Lindroos, M.Leskela, Solution Processing of Inorganic Materials, edited by D.B.Mitzi, John Wiley & Sons, Inc. 2009, 239-282. In this case, the ion precursor is first applied to the substrate, then dried and exposed to the reaction with the gas. The cycles are repeated until the desired layer thickness is reached. If necessary, the thin layer is still thermally treated. So far, thin layers of oxides, halides and chalcogenides have been prepared using the ILGAR method.

Direct application of a liquid reducing agent to a thin layer of precursor allows it to re-dissolve and reduce the formation of an uneven layer. This is due to the high surface tension of the reducing agent, which causes it to accumulate in droplets, which causes further agglomeration of Pt.

Existing processes for platinum deposition from solutions are problematic because, when Pt precursors are reduced in solutions, platinum nanoparticles agglomerate into oversized clusters when applied.

-4 on the substrate and subsequent low-temperature treatment, however, the adhesion is poor and the specific surface area is smaller.

Description of the invention

The subject of the invention is a novel method of preparing a low temperature Pt (platinum) catalyst using a gaseous phase reducing agent.

The novelty of this method is the application of the gaseous phase reducing agent. As a consequence, the quality of the layer depends only on the quality of the precursor application and the reaction between the gas and the precursor.

The advantages of this method are the relatively fast application method, good control over the particle size distribution and size, the possibility of application to all substrate shapes, and especially the low application and reduction temperature, which also allows application to thermally unstable substrates such as polymeric materials.

The Pt catalyst prepared in this way can be used as an electro-catalyst (Gratzel solar cells, fuel cells, electrooxidation of organic compounds) if Pt is applied to an electrically conductive substrate, and as an immobilized catalyst for chemical reactions.

The low temperature Pt catalyst of the present invention is characterized by a very good adhesion to the substrate (substrate) such as glass, ceramics, polymers, carbon, semiconductors, etc., and a high degree of catalytic efficiency.

The elemental platinum layer on the substrate is characterized by x-ray photoelectron spectroscopy (XPS), which confirms that 100% of the platinum is in the elemental state. Elemental platinum particles are smaller than 50 nm (estimate from SEM images) and are evenly distributed over the substrate surface. The adhesion to the substrate is very good as the platinum layer cannot be removed either by intensive wiping or scraping or in an ultrasonic bath.

-5The adequate size of platinum particles, the uniform distribution of these particles, the large specific surface area and their good adhesion to the substrate are due to the specific order of the processes or chemical reactions in the process described. These properties are achieved by first dissolving the Pt precursor dissolved in a suitable solvent evenly onto the substrate and drying the applied layer. Using a suitable reducing agent applied in the gas phase, the platinum is reduced to its elemental state. This prevents re-dissolving which would occur if the liquid reducing agent were applied directly to the precursor layer and, consequently, agglomeration of the particles upon reduction. At the same time, the uniform distribution of Pt nano-particles across the surface is maintained. Liquid reducing agents have a high surface tension, which, unlike the solvents used in the application of precursors, prevents the uniform application of Pt to the substrate surface, since they are collected in droplets before complete drying, which significantly increases the concentration of Pt and leads to the formation of large aggregates after drying. The reduction temperature is adjusted according to the vapor pressure of the reducing agent.

Description of the process according to the invention

Pictures show:

Figure 1 presents a SEM image of a nano-platinum applied by spin-coating method on a SnO ₂ : F-coated glass layer at 50,000 magnification.

Figure 2 represents a SEM image of a nano-platinum applied by spin-coating method on a SnO ₂ : F-coated glass layer at 100,000 magnification.

Figure 3 represents a SEM image of a nano-platinum applied by spin-coating method on a SnO ₂ : F-coated glass layer at 300,000 magnification.

Figure 4 represents a SEM image of a nano-platinum deposited by a drop-coating method on a SnO ₂ : F-coated glass layer at 100,000 magnification.

Figure 5 represents a SEM image of a nano-platinum deposited by a drop-coating method on a SnO ₂ : F-coated glass layer at 200,000 magnification.

-6Figure 6 is a SEM image of a nano-platinum deposited by a drop-coating method on a SnO ₂ : F-coated glass layer at 400,000 magnification.

Figure 7 represents the XPS spectrum of conductive glass and the Pt layer on conductive glass.

Figure 8 represents the XPS spectrum of platinum 4f in the platinum layer.

Figure 9 represents the first 10 cycles made by cyclic voltammetry in an iodide electrolyte.

Figure 10 represents 1000 cycles made in 0.1 M HCIO ₄ .

Figure 11 represents 1000 cycles made in an iodide electrolyte.

Figure 12 represents lOOte cycles of samples with different Pt masses applied in 0.1 M HCIO ₄ .

Figure 13 represents the lOOte cycles of samples deposited with different masses of Pt in the iodide electrolyte.

Figure 14 is a l-V graph of a compound gratzl solar cell.

The subject of the invention is a process for preparing a low temperature elemental platinum layer using a gaseous phase reducing agent. The process is characterized in that it contains the steps of:

a) Preparation of Pt precursor solution.

The precursor is a soluble platinum complex, preferably hexachloroplatinic (IV) acid (H ₂ PtCI ₆ ) and salts thereof.

Solvents are those known solvents that dissolve precursors of the invention and comprise water or organic compounds or a mixture of organic compounds or a mixture of water and organic compounds. Preferably, it is a mixture of water and alcohol, the alcohol being preferably ethanol and the alcohol-water ratio being more than 1: 1, preferably 97% EtOH.

b) Application of the Pt precursor to the substrate.

Substrates are substances that are thermally resistant to at least 100 ° C and chemically resistant to Pt precursor, solvent and reducing agent, preferential glass, polymers, ceramics, carbon, semiconductors, metal oxides.

c) Dehumidification of step b).

• ·

-7d) Reduction of the dried deposition of the Pt precursor from step b) to elemental platinum using a gaseous phase reducing agent.

The reducing agents of the invention are those which, at a temperature of up to 170 ° C in a gaseous residence, reduce the dried precursor within the scope of the invention, preferably are: formic acid, ethylene glycol, methanal, ethanal and propanal.

Level a)

Preferably, a solution of hexachloroplatinic (IV) acid H ₂ PtCI _{6 is} prepared in an organic solvent or a mixture of organic solvent and water, the organic solvent being preferably alcohol, more preferably 97% ethanol. The choice of solvent also affects the viscosity of the prepared H ₂ PtCI ₆ solution. The surface tension of the solvent and the hydrophilicity of the substrate are particularly important for the application of a uniform layer.

Level b)

Pt precursor from step a) is applied to the substrate:

1) by the technique of adsorption of the Pt complex onto the substrate surface, so that the substrate is immersed in the solution of step a) at a concentration of 10 ⁶ M to a saturated solution. The soaking time is from 1 minute to 24 hours, preferably 30 minutes. After soaking, the substrate is thoroughly washed with a clean solvent.

2) dip dip coating, so that the substrate is immersed in the solution from step a) and extracted at a steady rate. The velocity depends on the desired thickness of the applied layer, and is generally between 0.1 and 100 cm / min.

Organic molecules may be added to the solution, which crosslinks and increase the viscosity of the solution, e.g. Citric acid in EtOH, or coating the substrate to improve the adhesion of the precursor to the substrate surface, e.g. 1% solution of TD 80 etholate, allowing for the application of thicker and more even layers. They also affect the compactness of the resulting layers and

-8 subsequently to their specific surface. The problem, however, is that organic molecules can remain adsorbed to the surface and can reduce the catalyst's performance.

3) using the spin coating technique, by dropping the appropriate amount of solution from step a) onto a rotating substrate. The amount of Pt and the thickness of the layer are dependent on the concentration of the solution, the speed of rotation of the substrate and the size of the substrate. The rotation time of the substrate after application of the solution is from 10 seconds to 1 minute and depends on the time required for the sample to dry, with the amount of precursor applied preferably from 10 μί / cm ² to 100 pL / cm ² , more preferably 25 pL / cm ² and depends on the speed of rotation of the substrate and the solvent used. The spin speed of the spin coater is preferably from 500 to 10,000 rpm, more preferably 2000 rpm.

4) spray-coating, so that the solution from step a), with a concentration of 10 ' ^{5 6} M to a saturated solution, is sprayed over the surface of the substrate and allowed to dry. The volume of solution used is from 1 pL to 320 pL per 1 cm ^{2 of} substrate. The substrate temperature is from 0 to 150 ° C and depends on the solvent used.

5) using a drop-coating technique, pour the solution from step a) at a concentration of 10 ⁶ M to a saturated solution over the substrate surface and allow to dry. The volume of solution used is from 1 pL to 320 pL per 1 cm ^{2 of} substrate. The substrate temperature is from 0 to 150 “C, and depends on the solvent used.

Level c)

After precursor application, the sample is thoroughly dried at a temperature of from 0 to 170 ° C, preferably at room temperature. This step is essential to achieve good Pt adhesion to the substrate.

-9Stage d)

The dried application of step b) is exposed to the reducing agent in a gaseous state, the reducing agent being preferably formic acid heated to a temperature of 100 to 170 ° C, preferably

150 ° C for 1 to 60 min, preferably 15 min.

The application and reduction cycles can be arbitrarily repeated to increase the amount of Pt on the substrate. Multiple precursor application can be combined with any application technique. The maximum amount of Pt in single application and reduction depends on the technique used and increases from 1) to 5). The quantity and size of agglomerates is also increasing. The application technique also affects the uniformity of the applied layer, which falls from 1) to 5).

With the adsorption technique, it is possible to apply Pt catalyst on substrates of all shapes and not just flat plates.

Analytical methods

1. Linear electron microscopy (SEM)

Images were taken on a Zeiss ULTRA Plus line electron microscope. Figures 1 to 3 show the surface of the SnO ₂ : F-coated glass layer and applied Pt nano-particles using the spin-coating method at different magnifications. The large SnO ₂ crystals, which are randomly distributed over the surface, and the Pt particles, which can be seen as white dots, are well evident. Due to the deposition technique, the Pt particles are distributed mainly around the larger SnO ₂ crystals and between the contacts of these crystals where they are trapped during the precursor application. Figure 3 clearly shows the Pt particle size, which is only a few nm.

Figures 4 to 6 show the surface of SnO ₂ : F-coated glass and applied Pt nano-particles using the drop-coating method at different magnifications. For better control of the amount of Pt applied, it can be accurately determined here and in this case is 15.6 pg / cm ² . Platinum represents white dots overlying larger SnO ₂ crystals. Figure 6 shows

-10that has a large specific surface area due to the disconnection of the Pt particles, and the particle size is a few nm.

2. X-ray Photoelectron Spectrometry (XPS)

We recorded the XPS on a PHI-TFA XPS spectrometer. Figure 7 represents the XPS spectrum of SnO ₂ : F coated glass with and without Pt coating. Figure 8 represents the excerpt from Figure 7 in the 4f Pt range, indicating that the peak positions are in perfect agreement with the elemental platinum signal (dashed line). This confirms that Pt prepared with this method is completely reduced.

3. Cyclic voltammetry (CV)

Cyclovoltammograms were recorded on an EG&G PAR273 potentiostaomt-galvanostat using the Model 270 Electrochemical analysis Softwere software. Iodide electrolyte is a good approximation of the electrolyte used in Gratzl solar cells, and its composition is as follows: 0.5 M lithium perchlorate, 50 mM lithium iodide and 10 mM iodine in propylene carbonate (PC). Figure 9 represents the first 10 cycles of the sample with 15.6 pg / cm ² Pt made in the iodide electrolyte. The graph shows that the catalyst stabilizes after a few cycles, but its performance actually improves. Figures 10 and 11, which represent the first 1000 cycles in the acid or iodide electrolyte, respectively, and confirm the stability of the catalyst even after prolonged use.

Figures 12 and 13 represent hundreds of cycles of samples with varying amounts of Pt deposited, cyclans in 0.1 M HCIO ₄ and in an iodide electrolyte. The graphs show that the catalytic activity increases with increasing amount of Pt, but the activity is evident even at relatively low amounts (below 1 pg / cm ² ).

4. Making Gratzl Solar Cells with Data

The cells consisted of commercially available materials that we purchased from Solaronix. The working electrode was prepared by applying a TiO ₂ paste to a surface of 1 cm ² on glasses (SnO ₂ : F, Solaronix, Ro = 7 Ω ¹ , OTE-optically transparent electrode) 2.5 x

-112.5 cm and sintered at 450 ° C for 30 minutes. The electrode was then immersed in a dye solution (Ruthenizer 535-bis-TBS, Solaronix, 20 mg / 50 mL in ethanol). After ten hours, the electrode was well washed and dried. The opposite electrode was prepared by applying Pt to the OTE by a drop-coating method and chemically reduced with formic acid vapor at 150 ° C. When the cells were assembled, they were additionally covered with a 1 cm ² mask to prevent the effect of unwanted light.

The performance of the compound cell was tested with 73 Oriel® Sol3A ™ Class AAA Solar Simulators. Main characteristics such as V _oc (open circuit voltage), J _sc (short circuit current density), Fill Factor (FF) and efficiency are given in the table:

Voc (V) Jsc (mA / cm ² ) Fill Factor Utilization (%) 0,682752 0,009261 55,6489 3,7198

Figure 14 is a lV graph (current vs. voltage) of a composite cell from which the FF can be determined, which represents the relationship between theoretical maximum efficiency and actual, and maximum power (P _max ) and current and voltage at maximum power (l _max , V _max ).

P _max (mW) lmax (A) V _max (V) 3,518619 0,00783 0,449352

Implementation examples

Example 1

The glass plate is immersed in a solution of H ₂ PtCl6 in ethanol. After 10 minutes in the solution, the plate is removed and thoroughly washed with ethanol. After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 2

The glass plate is immersed in 0.02 M solution of H ₂ PtCL in ethanol and extracted evenly at a rate of 10 cm / min. After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 3

-120.02 M solution of H ₂ PtCI ₆ in ethanol is dripped onto a rotating glass tile so that the solution is evenly spilled over the tile. The speed of rotation is 2000 rpm. The volume of solution used is more than 16 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 4

An appropriate amount of 0.02 M solution of H ₂ PtCl6 in ethanol is uniformly dispersed over a glass plate heated to 70 ° C, so that the amount of solution is 4 pL / cm ² . The sample is then exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 5

The 0.02 M solution of H ₂ PtCI ₆ in ethanol is poured evenly over the glass tile so that the amount of solution is 4 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 6

The polymer film is immersed in a solution of H ₂ PtCI ₆ in ethanol. After 10 minutes in the solution, remove the film and rinse thoroughly with ethanol. After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 7

The polymer film is immersed in 0.02 M solution of H ₂ PtCI ₆ in ethanol and extracted evenly at a rate of 10 cm / min. After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 8

-130.02 M solution of H ₂ PtCI ₆ in ethanol is dripped onto a rotating polymer film so that the solution is evenly poured over the film. The speed of rotation is 2000 rpm. The volume of solution used is more than 16 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 9

An appropriate amount of 0.02 M solution of H ₂ PtCI ₆ in ethanol is uniformly dispersed over the polymer film heated to 70 ° C so that the amount of solution is 4 pL / cm ² . The sample is then exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 10

The 0.02 M solution of H ₂ PtCI ₆ in ethanol is poured evenly over the polymer film so that the amount of solution is 4 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 11

The polymer film with a conductive layer is immersed in a solution of H ₂ PtCI ₆ in ethanol. After 10 minutes in the solution, remove the film and rinse thoroughly with ethanol. After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 12

-14Polymer film with conductive layer is immersed in 0.02 M solution of H ₂ PtCI ₆ in ethanol and extracted evenly at a rate of 10 cm / min. After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 13

A 0.02 M solution of H ₂ PtCI ₆ in ethanol is dripped onto a rotating polymer film with a conductive layer so that the solution is evenly spilled over the film. The speed of rotation is 2000 rpm. The volume of solution used is more than 16 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 14

The appropriate amount of 0.02 M solution of Η ₂ Ρΐϋβ in ethanol is uniformly dispersed over a polymer film with a conductive layer heated to 70 ° C, so that the amount of solution is 4 pL / cm ² . The sample is then exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 15

The 0.02 M solution of H ₂ PtCI ₆ in ethanol is poured evenly over a polymer film with a conductive layer so that the amount of solution is 4 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 16

The glass plate with the conductive layer is immersed in a solution of H ₂ PtCI ₆ in ethanol. After 10 minutes in the solution, the plate is removed and thoroughly washed with ethanol. After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 17

The glass plate with the conductive layer is immersed in 0.02 M solution of H ₂ PtCI ₅ in ethanol and extracted evenly at a rate of 10 cm / min. After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

-15Example 18

A 0.02 M solution of H ₂ PtCI ₆ in ethanol is dripped onto a rotating glass plate with a conductive layer so that the solution is evenly spilled across the plate. Rotation speed is 2000 rpm Tue. The volume of solution used is more than 16 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 19

The appropriate amount of 0.02 M solution of H ₂ PtCl6 in ethanol is uniformly dispersed over a glass plate with a conductive layer heated to 70 ° C, so that the amount of solution is 4 pL / cm ² . The sample is then exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 20

The 0.02 M solution of H ₂ PtCI ₆ in ethanol is poured evenly over a glass plate with a conductive layer so that the amount of solution is 4 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to formic acid vapor at 150 ° C for 15 minutes.

Example 21

The glass plate is immersed in a solution of H ₂ PtCI ₆ in ethanol. After 10 minutes in the solution, the plate is removed and thoroughly washed with ethanol. After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 22

The glass plate is immersed in 0.02 M solution of H ₂ PtCl6 in ethanol and extracted evenly at a rate of 10 cm / min. After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 23

-160.02 M solution of H ₂ PtCI ₆ in ethanol is dripped onto a rotating glass tile so that the solution is evenly spilled over the tile. The speed of rotation is 2000 rpm. The volume of solution used is more than 16 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 24

An appropriate amount of 0.02 M solution of H ₂ PtCl6 in ethanol is uniformly dispersed over a glass plate heated to 70 ° C, so that the amount of solution is 4 pL / cm ² . The sample is then exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 25

The 0.02 M solution of H ₂ PtCl6 in ethanol is poured evenly over the glass tile so that the amount of solution is 4 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 26

The polymer film is immersed in a solution of H ₂ PtCl ₆ in ethanol. After 10 minutes in the solution, remove the film and rinse thoroughly with ethanol. After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

-17Example 27

The polymer film is immersed in 0.02 M solution of H ₂ PtCI ₆ in ethanol and extracted evenly at a rate of 10 cm / min. After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 28

The 0.02 M solution of H ₂ PtCI ₆ in ethanol is dripped onto a rotating polymer film so that the solution is evenly poured over the film. The speed of rotation is 2000 rpm. The volume of solution used is more than 16 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 29

An appropriate amount of 0.02 M solution of H ₂ PtCl6 in ethanol is uniformly dispersed over the polymer film heated to 70 ° C so that the amount of solution is 4 pL / cm ² . The sample is then exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 30

The 0.02 M solution of H ₂ PtCl6 in ethanol is poured evenly over the polymer film so that the amount of solution is 4 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 31

The polymer film with a conductive layer is immersed in a solution of H ₂ PtCI ₆ in ethanol. After 10 minutes in the solution, remove the film and rinse thoroughly with ethanol. After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 32

The polymer film with a conductive layer is immersed in a 0.02 M solution of H ₂ PtClG in ethanol and extracted evenly at a rate of 10 cm / min. After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

-18Example 33

A 0.02 M solution of H ₂ PtCI ₆ in ethanol is dripped onto a rotating polymer film with a conductive layer so that the solution is evenly spilled over the film. The speed of rotation is 2000 rpm. The volume of solution used is more than 16 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 34

The corresponding amount of 0.02 IVI solution of H ₂ PtCI ₆ in ethanol is uniformly dispersed over the polymer film with the conductive layer heated to 70 ° C, so that the amount of solution is 4 pL / cm ² . The sample is then exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 35

The 0.02 M solution of H ₂ PtCI ₆ in ethanol is poured evenly over a polymer film with a conductive layer so that the amount of solution is 4 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 36

The glass plate with the conductive layer is immersed in a solution of H ₂ PtCI ₆ in ethanol. After 10 minutes in the solution, the plate is removed and thoroughly washed with ethanol. After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

• · · ·

Example 37

The glass plate with the conductive layer is immersed in 0.02 M solution of H ₂ PtCl6 in ethanol and extracted evenly at a rate of 10 cm / min. After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 38

A 0.02 M solution of H ₂ PtCl6 in ethanol is dripped onto a rotating glass plate with a conductive layer so that the solution is evenly spilled across the plate. The speed of rotation is 2000 rpm. The volume of solution used is more than 16 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 39

The appropriate amount of 0.02 M solution of H ₂ PtCl6 in ethanol is uniformly dispersed over a glass plate with a conductive layer heated to 70 ° C, so that the amount of solution is 4 pL / cm ² . The sample is then exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

Example 40

The 0.02 M solution of H ₂ PtCI ₆ in ethanol is poured evenly over a glass plate with a conductive layer so that the amount of solution is 4 pL / cm ² . After drying at room temperature for 15 minutes, the sample is exposed to ethylene glycol vapor at 150 ° C for 15 minutes.

The process of the invention thus comprises the steps of preparing a Pt precursor solution, applying the Pt precursor to the substrate, drying the coating and reducing the dried coating of the Pt precursor, the reduction being carried out at a temperature up to 170 ° C, preferably at 150 ° C, using a reducing agent in the gaseous phase . Pt precursor is a soluble platinum complex, preferably

-20hexachloroplatinic acid (H ₂ PtCle) and its salts. A solvent is water or an organic compound or a mixture of organic compounds or a mixture of water and organic compounds that dissolves a precursor of the present invention, preferably a mixture of water and alcohol, the alcohol being preferably ethanol and the alcohol-water ratio being more than 1: 1 , preferably 97% EtOH. The substrate is a substance that is thermally stable to at least 100 ° C and chemically resistant to Pt precursor, solvent and reducing agent, preferably glass, polymers, ceramics, carbon, semiconductors, metal oxides. A reducing agent is a compound which, at a temperature of up to 170 ° C in a gaseous residence, reduces the dried precursor of the invention, preferably formic acid, ethylene glycol, methanal, ethanal and propanal. Options for precursor application are soaking adsorption, sol-gel process, spin coating, spray coating, drop coating or any combination of all techniques.

The Gratzel solar cell according to the invention contains a counter electrode prepared according to the process of the invention.

Immobilized Pt catalysts prepared by the process of the invention.

Pt electro-catalyst prepared according to the process of the invention.

Claims (8)

Patent claims 1. A process for preparing a thin layer of Pt catalyst, wherein the process comprises the steps of preparing a Pt precursor solution, applying the Pt precursor to the substrate, drying the coating and reducing the dried coating of the Pt precursor, characterized in that the reduction takes place at a temperature up to 170 ° C, preferably at 150 ° C using a gaseous phase reducing agent. 2. The process of claim 1, wherein the Pt precursor is a soluble platinum complex, preferably hexachloroplatinic acid (lEPtCU) and salts thereof. Process according to claim 1, characterized in that the solvent is water or an organic compound or a mixture of organic compounds or a mixture of water and organic compounds that dissolves the precursor of the present invention, preferably a mixture of water and alcohol, the alcohol being preferably ethanol and the alcohol to water ratio is more than 1: 1, preferably 97% EtOH. Process according to claim 1, characterized in that the substrate is a substance that is thermally stable to at least 100 ° C and chemically resistant to Pt precursor, solvent and reducing agent, preferred glass, polymers, ceramics, carbon, semiconductors, metal oxides . Process according to claim 1, characterized in that the reducing agent is a compound which, at a temperature of up to 170 ° C in the gaseous state, reduces the dried precursor of the invention, preferably formic acid, ethylene glycol, methanal, ethanal and propanal. Process according to claim 1, characterized in that the precursor application options are soaking adsorption, sol-gel process, spin coating, spray coating, drop coating or any combination of all techniques. A Gratzel solar cell containing the counter electrode prepared according to claim 1. An immobilized Pt catalyst prepared according to claim 1. -229. Pt electro-catalyst prepared according to claim 1.