阅读说明：本技术 一种用于废气净化催化剂的铂化合物合成方法及应用 (Synthetic method and application of platinum compound for exhaust gas purification catalyst ) 是由 栾浩 于 2019-10-16 设计创作，主要内容包括：本发明提出了一种用于废气净化催化剂的铂化合物合成方法,使用H2PtCl6作为原料,通过碱液反应水解生成氢氧化铂沉淀,氢氧化铂使用硝酸铵配位后获得中间产物,再进一步与氨水配位后最终生成硝酸铵铂。本发明还提出了用上述制备方法制得的硝酸铵铂的应用。本发明工艺较简单,过程基本无损耗,产率高,制备后的催化剂铂晶粒细,达到纳米级别,分散度高,具有优异的催化性能及抗老化能力,有效提高催化剂寿命。(The invention provides a method for synthesizing a platinum compound for a waste gas purification catalyst, which uses H2PtCl6 as a raw material, generates platinum hydroxide precipitate through alkali liquor reaction and hydrolysis, obtains an intermediate product after platinum hydroxide is coordinated by ammonium nitrate, and finally generates ammonium platinum nitrate after the platinum hydroxide is further coordinated with ammonia water. The invention also provides the application of the platinum ammonium nitrate prepared by the preparation method. The method has the advantages of simple process, basically no loss in the process, high yield, fine platinum crystal grains of the prepared catalyst, nano-level achievement, high dispersity, excellent catalytic performance and ageing resistance, and effective improvement of the service life of the catalyst.)

1. A method for synthesizing a platinum compound for an exhaust gas purifying catalyst, characterized by comprising the steps of:

s1) adding water into the H2PtCl6 solution for dilution, keeping stirring, adding an alkali solution to generate a precipitate, and then filtering and washing to obtain a solid of polyhydrated platinum hydroxide;

s2) placing the solid of the polyhydrated platinum hydroxide obtained in the step S1) in an oven, and drying to obtain a solid of the monohydrate platinum hydroxide;

s3) adding the solid of the platinum hydroxide monohydrate obtained in the step S2) into the ammonium nitrate solution acidified by nitric acid, heating in a water bath, keeping stirring, gradually dissolving the solid of the platinum hydroxide monohydrate to generate a platinum nitrate-platinum ammonium nitrate reset complex solution;

s4) adding ammonia water into the platinum nitrate-platinum ammonium nitrate reset complex solution obtained in the step S3), and stirring to obtain a platinum ammonium nitrate solution.

2. The method for synthesizing a platinum compound according to claim 1, wherein the mass concentration of the H2PtCl6 solution in the step S1) is 0.5-35%, the mass concentration of the alkali solution is 1-30%, and the mass ratio of the H2PtCl6 solution to the alkali solution is 1 (0.3-1).

3. The method for synthesizing platinum compound according to claim 1, wherein the solid polyhydrated platinum hydroxide obtained in step S1) has a chemical formula of pt (oh) 2. nH2O, wherein n is an integer of 1 to 12.

4. The method for synthesizing a platinum compound according to claim 1, wherein the conditions for drying in the oven in step S2) are as follows: the temperature is 60-150 ℃, the pressure is 0.2-1.2 MPa, the relative humidity is 10-85%, and the drying time is 0.5-12 hours.

5. The method for synthesizing a platinum compound according to claim 1, wherein the mass concentration of the ammonium nitrate solution in the step S3) is 0.5 to 30%, and the mass ratio of the platinum hydroxide monohydrate solid to the ammonium nitrate solution is 1: (1-50).

6. The method for synthesizing a platinum compound according to claim 1, wherein the temperature of the water bath heating in step S3) is 35 to 90 ℃.

7. The method for synthesizing a platinum compound according to claim 1, wherein the mass concentration of the aqueous ammonia in step S4) is 2% to 20%.

8. The method for synthesizing a platinum compound according to claim 1, wherein the alkali solution in step S1) is any one or more of potassium hydroxide, barium hydroxide, strontium hydroxide, lithium hydroxide, or rubidium hydroxide.

9. Use of the platinum ammonium nitrate obtained by the platinum compound synthesis method according to claim 1, wherein the platinum ammonium nitrate is used for preparing a platinum catalyst.

Technical Field

The invention relates to the field of noble metal catalysts, in particular to a synthesis method and application of a platinum compound used for an exhaust gas purification catalyst.

Background

With the rapid increase of the number of motor vehicles, the pollution of the motor vehicle exhaust emission is increasing. According to statistics, every thousand motor vehicles discharge about 3000kg of carbon monoxide, 200-400 kg of hydrocarbon and 50-150 kg of oxynitride every day. In large and medium-sized cities in China, the exhaust emission of motor vehicles becomes a main air pollution source. The most major pollutants of motor vehicle exhaust: carbon monoxide (CO), Hydrocarbon (HC), nitrogen oxide (NOx), sulfur dioxide (SO2), particulate matters (PM-10), lead (Pb) and the like cause great harm to human health and ecological environment. Therefore, it is very necessary to increase the control force of the motor vehicle to discharge pollutants and effectively protect the environment while the motor vehicle industry is vigorously developed to promote the development of social economy.

The European emission regulation system is introduced in China in 2001, GB18352.1-2001 national first-stage emission standard (called 'nation I' for short) which is equivalent to European standard I is implemented, the emission standard is continuously improved, the national emission standard I to the national emission standard V are implemented from 2001 to 2018, and the national emission standard six which is the most advanced and strict in the world at present is implemented in 2020; and the ultimate goal is to achieve zero emission of pollutants.

The exhaust gas purifying catalyst for motor vehicle is one key part for controlling and lowering the exhaust emission of motor vehicle and has three-way catalyst TWC, oxidation catalyst DOC, natural gas converting catalyst GOC, selective catalytic reduction catalyst SCR, gasoline engine exhaust particle trapping and purifying catalyst CGPF, diesel engine particle trapping and purifying catalyst CDPF, four-way catalyst FWC, lean burn catalyst LNC, etc. based on different fuel and work principle.

Except SCR, the core active components of the rest catalysts are all noble metals of platinum, palladium and rhodium. The noble metal has excellent catalytic conversion activity and ageing resistance and is expensive, and although the academic world invests a great deal of manpower and material resources for many years to carry out noble metal substitution research, the noble metal cannot be substituted by other materials.

The application technology of the noble metal becomes the most key and most core technology of the exhaust purification catalyst, but the actual application of the catalyst is restricted due to the low performance and the large consumption of the noble metal caused by the dispersion degree of the noble metal on the catalyst, the poor grain fineness of the noble metal and the lower activity of the noble metal single crystal at present.

Disclosure of Invention

The invention provides a method for synthesizing a platinum compound for a waste gas purification catalyst, which solves the problems that the existing noble metal platinum usually forms large-particle crystals on the catalyst, the catalytic efficiency is low, and the anti-aging capability is weak.

In order to solve the technical problems, the invention adopts the technical scheme that: a method for synthesizing a platinum compound for an exhaust gas purification catalyst, comprising the steps of:

s1) adding water into the H2PtCl6 solution for dilution, keeping stirring, adding an alkali solution to generate a precipitate, and then filtering and washing to obtain a solid of polyhydrated platinum hydroxide;

s2) placing the solid of the polyhydrated platinum hydroxide obtained in the step S1) in an oven, and drying to obtain a solid of the monohydrate platinum hydroxide;

s3) adding the solid of the platinum hydroxide monohydrate obtained in the step S2) into the ammonium nitrate solution acidified by nitric acid, heating in a water bath, keeping stirring, and gradually dissolving the solid of the platinum hydroxide monohydrate to generate a platinum nitrate-platinum ammonium nitrate reset complex;

s4) adding ammonia water into the platinum nitrate-platinum ammonium nitrate reset coordination compound obtained in the step S3) to obtain a platinum ammonium nitrate solution.

Preferably, in the step S1), the mass concentration of the H2PtCl6 solution is 0.5-35%, the mass concentration of the alkali solution is 1-30%, and the mass ratio of the H2PtCl6 solution to the alkali solution is 1 (0.3-1).

Preferably, the solid polyhydrated platinum hydroxide obtained in the step S1) has a chemical formula of Pt (OH) 2. nH2O, wherein n is an integer of 1-12.

Preferably, the drying conditions in the oven in step S2) are as follows: the temperature is 60-150 ℃, the pressure is 0.2-1.2 MPa, the relative humidity is 10-85%, and the drying time is 0.5-12 hours.

Preferably, the mass concentration of the ammonium nitrate solution in the step S3) is 0.5-30%, and the mass ratio of the platinum hydroxide monohydrate solid to the ammonium nitrate solution is 1: (1-50).

Preferably, the temperature of the water bath heating in the step S3) is 35 to 90 ℃.

Preferably, the mass concentration of the ammonia water in the step S4) is 2% to 20%.

Preferably, the alkali solution in step S1) is any one or more of potassium hydroxide, barium hydroxide, strontium hydroxide, lithium hydroxide, or rubidium hydroxide.

Compared with the prior art, the invention has the beneficial effects that: the method has the advantages of simple process, basically no loss in the process, high yield, fine platinum crystal grains of the prepared catalyst, nano-level achievement, high dispersity, excellent catalytic performance and ageing resistance, and effective improvement of the service life of the catalyst.

Drawings

FIG. 1 is a transmission electron microscope image of platinum grains in a platinum rhodium catalyst synthesized by an application example.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto. For process parameters not specifically noted, reference may be made to conventional techniques.

The invention provides a method for synthesizing a platinum compound used for an exhaust gas purification catalyst, which comprises the following steps: