CN115739113A - Catalyst for catalyzing formaldehyde at room temperature and preparation method thereof - Google Patents

Abstract

The invention provides a catalyst for catalyzing formaldehyde at room temperature and a preparation method thereof. The method comprises the following steps: dissolving nickel nitrate hexahydrate and aluminum nitrate nonahydrate in a mixed solution of polyethylene glycol and cyclohexane; step two, dropwise adding ammonia water into the solution obtained in the step one, then aging, centrifuging, washing and drying to obtain a nickel-aluminum composite oxide carrier; preparing boehmite by using aluminum nitrate nonahydrate, cutting into pieces, and introducing a nickel-aluminum composite oxide carrier into the boehmite to obtain a catalyst precursor; soaking the catalyst precursor in chloroplatinic acid solution, and pumping to dry; and step five, reducing the product obtained in the step four by using a sodium borohydride reducing agent, and then stirring, centrifuging, washing and drying to obtain the catalyst. High catalytic efficiency, low cost, no toxicity and no harm.

Description

Catalyst for catalyzing formaldehyde at room temperature and preparation method thereof

technical field

The invention relates to the technical field of catalysts, in particular to a catalyst for catalyzing formaldehyde at room temperature and a preparation method thereof.

Background technique

Formaldehyde is recognized globally as the most common hydrocarbon in indoor air pollution and ranks second in the list of toxic and harmful air pollutants issued by the Chinese government. Its sources are mainly various building materials and interior decoration materials (furniture, paint, leather), etc. Long-term exposure to formaldehyde can cause diseases such as nasal tumors, skin cancer, and respiratory system damage, and cause serious harm to human health. Therefore, there is an urgent need to effectively reduce the formaldehyde level in the air to improve air quality. For example, Chinese patent CN101497042A discloses a high-efficiency catalyst for high-concentration formaldehyde oxidation. The catalyst uses hydrotalcite as a carrier and Pt single atoms as active centers, and can eliminate industrial high-concentration formaldehyde tail gas at room temperature. However, the required Pt load is large and the cost is high.

Contents of the invention

The present invention solves one of the problems existing in the prior art to a certain extent. Therefore, an object of the present invention is to propose a catalyst for catalyzing formaldehyde at room temperature, which has the advantages of high catalytic efficiency, low cost, and non-toxic and harmless.

The above-mentioned purpose is achieved through the following technical solutions:

A catalyst for catalyzing formaldehyde at room temperature comprises an active component and a carrier, wherein the active component includes platinum nanoparticles, and the carrier is a mixture of nickel-aluminum composite hydrotalcite and boehmite.

As a further improvement of the present invention, the loading amount of the platinum nanoparticles on the carrier is greater than 0wt% and less than 1wt%.

As a further improvement of the present invention, the loading amount of the platinum nanoparticles on the carrier is 0.2wt%.

As a further improvement of the present invention, the molar ratio of nickel and aluminum in the nickel-aluminum composite hydrotalcite is 1:9 or 1:7 or 1:5.

Another object of the present invention is to propose a method for preparing a catalyst for catalytic oxidation of formaldehyde,

The above-mentioned purpose is achieved through the following technical solutions:

A preparation method of a catalyst for catalytic oxidation of formaldehyde, for preparing a catalyst for catalytic formaldehyde at room temperature as described in any one of claims 1-4, characterized in that, comprising the steps of:

Step 1, dissolving nickel nitrate hexahydrate and aluminum nitrate nonahydrate in a mixed solution of polyethylene glycol and cyclohexane;

In step 2, add ammonia water dropwise to the solution obtained in step 1, then age, centrifuge, wash, and dry, so as to obtain a nickel-aluminum composite oxide carrier;

Step 3, preparing boehmite with aluminum nitrate nonahydrate, cutting it into pieces, and introducing the nickel-aluminum composite oxide carrier into the boehmite to obtain a catalyst precursor;

Step 4, immersing the catalyst precursor in the chloroplatinic acid solution, and draining;

In step five, the product obtained in step four is reduced with sodium borohydride reducing agent, then stirred, centrifuged, washed and dried to obtain a catalyst.

As a further improvement of the present invention, in step 2, the mass fraction of the ammonia water is 25-28wt%.

As a further improvement of the present invention, the drying temperature in the second step is 60-90° C., and the drying time is 15 hours; the drying temperature in the fifth step is 60-90° C., and the drying time is 12 hours.

As a further improvement of the present invention, in Step 3, the step of cutting the boehmite into slices specifically includes: cutting the boehmite into thin slices with a size of 10mm×10mm×2mm.

As a further improvement of the present invention, the concentration of the sodium borohydride reducing agent is 0.572mol·L ^-1 .

Compared with the prior art, the present invention at least includes the following beneficial effects:

1. The present invention proposes a catalyst for catalyzing formaldehyde at room temperature and a preparation method thereof. The mixture of nickel-aluminum composite hydrotalcite and boehmite is used as a carrier to provide abundant alkaline and redox active sites for the adsorption of formaldehyde. And at the same time, it works synergistically with Pt nanoparticles, using Pt nanoparticles as the catalytic center, can promote the dissociation of adsorbed oxygen, thereby forming active oxygen for oxidizing formaldehyde, with the advantages of high catalytic efficiency, low cost, and non-toxic and harmless.

2. Due to the synergistic effect between NiAl ₉ -LDHs, Pt NPs and boehmite, the composite material has enhanced formaldehyde catalytic oxidation activity at room temperature, and can efficiently decompose formaldehyde into CO2 with a small amount of Pt NPs And H2O, low cost, non-toxic and harmless.

3. Boehmite provides a large number of surface hydroxyl groups, which increases the active area of the catalyst surface by dispersing Pt nanoparticles.

Description of drawings

Fig. 1 is a transmission electron microscope image of the catalyst Pt0.2/NiAl9-LDHs/AlOOH in the embodiment.

Detailed ways

The following examples illustrate the invention, but the invention is not limited by these examples. Modifications to the specific implementation of the present invention or equivalent replacement of some technical features without departing from the spirit of the present invention should be included in the scope of the technical solution claimed in the present invention.

Embodiment one:

As shown in Figure 1, a catalyst for catalyzing formaldehyde at room temperature includes an active component and a carrier, wherein the active component includes platinum nanoparticles, and the carrier is a mixture of nickel-aluminum composite hydrotalcite and boehmite.

The present invention proposes a catalyst for catalyzing formaldehyde at room temperature, which uses a mixture of nickel-aluminum composite hydrotalcite and boehmite as a carrier to provide abundant alkalinity and redox active sites for the adsorption of formaldehyde, and at the same time combine with Pt The synergistic effect of nanoparticles, with Pt nanoparticles as the catalytic center, can promote the dissociation of adsorbed oxygen, thereby forming reactive oxygen species for oxidizing formaldehyde.

The boehmite of the present invention provides a large number of surface hydroxyl groups, and increases the active area of the catalyst surface by dispersing Pt nanoparticles.

Due to the synergistic effect between NiAl ₉ -LDHs, Pt NPs and boehmite, the composite material has enhanced formaldehyde catalytic oxidation activity at room temperature, and can efficiently decompose formaldehyde into CO2 and CO2 with a small amount of Pt NPs. H2O, low cost, non-toxic and harmless.

The loading amount of the platinum nanoparticles on the carrier is greater than 0wt% and less than 1wt%. In this embodiment, based on the calculation that the total weight of the carrier is 100%, the loading amount of the platinum nanoparticles on the carrier is 0.2wt%.

The molar ratio of nickel and aluminum in the nickel-aluminum composite hydrotalcite is 1:9 or 1:7 or 1:5. In this embodiment, the molar ratio of nickel and aluminum in the nickel-aluminum composite hydrotalcite is 1:9.

In this embodiment, the boehmite is alumina hydrate (AlOOH).

Embodiment two:

A preparation method of a catalyst for catalytic oxidation of formaldehyde, for preparing a catalyst for catalytic formaldehyde at room temperature described in Example 1, comprising the steps of:

Step 1, dissolving nickel nitrate hexahydrate and aluminum nitrate nonahydrate in a mixed solution of polyethylene glycol and cyclohexane;

In step 2, add ammonia water dropwise to the solution obtained in step 1, then age, centrifuge, wash, and dry, so as to obtain a nickel-aluminum composite hydrotalcite carrier;

Step 3, preparing boehmite with aluminum nitrate nonahydrate, cutting it into pieces, and introducing the nickel-aluminum composite hydrotalcite carrier into the boehmite to obtain a catalyst precursor;

Step 4, immersing the catalyst precursor in the chloroplatinic acid solution, and draining;

In step five, the product obtained in step four is reduced with sodium borohydride reducing agent, then stirred, centrifuged, washed and dried to obtain a catalyst.

In step 2, the mass fraction of the ammonia water is 25-28wt%.

In the second step, the drying temperature is 60-90° C., and the drying time is 15 hours.

In Step 3, the step of cutting the boehmite into slices specifically includes: cutting the boehmite into thin slices with a size of 10mm×10mm×2mm.

In step five, the drying temperature is 60-90° C., and the drying time is 12 hours.

In step five, the concentration of the sodium borohydride reducing agent is 0.572 mol·L ^-1 .

The present invention proposes a method for preparing a formaldehyde catalyst at room temperature, using a mixture of nickel-aluminum composite hydrotalcite and boehmite as a carrier, which provides abundant alkaline and redox active sites for the adsorption of formaldehyde, and at the same time Synergizing with Pt nanoparticles, using Pt nanoparticles as the catalytic center, can promote the dissociation of adsorbed oxygen, thereby forming active oxygen for oxidizing formaldehyde.

Embodiment three:

Step 1, weigh 20.5g of polyethylene glycol (PEG400), add 100mL of cyclohexane, mix by magnetic stirring, then quickly add 20mL of 1mmol Ni(NO ₃ ) ₂ 6H ₂ O and 9mmol Al(NO ₃ ) ₂ . 9H ₂ O solution;

Step 2: After 10 min, 4.25 ml of ammonia water (28 wt%) was added dropwise to the solution obtained in Step 1, and the resulting mixture was aged in an oven at 60-90° C. for 2 h. The suspension was centrifuged, and the collected solid was washed 3 times with ultrapure water and ethanol;

In step three, the solid obtained in step two is dried in an oven at 60-90° C. for 15 hours to obtain the carrier NiAl ₉ . Then 10 mmol of Al(NO ₃ ) ₂ ·9H ₂ O was used to prepare pure Al support, and the product was boehmite (AlOOH). NiAl ₉ was introduced into boehmite flakes to obtain the catalyst precursor NiAl ₉ -LDHs/AlOOH.

Step 4: Weigh 300 mg of catalyst precursor into 10 ml of ultrapure water, then add H ₂ PtCl ₆ solution under continuous magnetic stirring; after soaking for 1 hour, quickly add 5 ml of sodium borohydride (0.572 mol·L ^-1 ) and hydrogen A suspension of sodium oxide (0.25mol·L ^-1 ) mixed with an aqueous solution. After continuous stirring for 1 h, it was centrifuged, and the collected solid was washed 4 times with ultrapure water and ethanol; the obtained solid was dried in an oven at 60-90° C. for 12 h, and the Pt loading was 0.2%.

For testing, the Pt _0.2 NiAl ₉ -LDHs/AlOOH obtained in Example 3 above was placed on a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and gas chromatography was used for quantitative analysis. The reaction results show that Pt _0.2 NiAl ₉ -LDHs/AlOOH can completely decompose 800ppm formaldehyde within 5h, and the catalyst remains stable without deactivation within 24h.

Embodiment four:

Step 1, weigh 20.5g polyethylene glycol (PEG400), add 100mL cyclohexane, mix by magnetic stirring, then quickly add 20ml containing 1mmol Ni(NO ₃ ) ₂ 6H ₂ O and 7mmol Al(NO ₃ ) ₂ . 9H ₂ O solution;

Step 2: After 10 minutes, 4.25ml of ammonia water (28wt%) was added dropwise to the solution obtained above, and the obtained mixture was aged in an oven at 60-90° C. for 2 hours. The suspension was centrifuged, and the collected solid was washed 3 times with ultrapure water and ethanol;

In step three, the solid obtained in step two is dried in an oven at 60-90° C. for 15 hours to obtain a carrier NiAl ₉ . Then 10 mmol of Al(NO ₃ ) ₂ ·9H ₂ O was used to prepare pure Al support, and the product was boehmite (AlOOH). Introduce NiAl ₉ into boehmite flakes to obtain catalyst precursor NiAl ₉ -LDHs/AlOOH;

Step 4, weigh 300 mg of catalyst precursor in 10 ml of ultrapure water, and then add H ₂ PtCl ₆ solution under continuous magnetic stirring; after soaking for 1 hour, quickly add 5 ml of sodium borohydride (0.572 mol ^L Sodium (0.252mol·L ^-1 ) suspension mixed with aqueous solution. After continuous stirring for 1 h, it was centrifuged, and the collected solid was washed 4 times with ultrapure water and ethanol; the obtained solid was dried in an oven at 60-90° C. for 12 h, and the Pt loading was 0.2%.

For detection, the Pt _0.2 NiAl ₉ -LDHs/AlOOH obtained in the above-mentioned Example 4 was placed on a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and gas chromatography was used for quantitative analysis. The reaction results show that Pt _0.2 NiAl ₉ -LDHs/AlOOH can completely decompose 650ppm formaldehyde within 5 hours, and the catalyst remains stable without deactivation within 24 hours.

Embodiment five:

Step 1, weigh 20.5g polyethylene glycol (PEG 400), add 100mL cyclohexane, mix by magnetic stirring, then quickly add 20ml containing 1mmol Ni(NO ₃ ) ₂ 6H ₂ O and 5mmol Al(NO ₃ ) ₂ · 9H ₂ O solution;

Step 2: After 10 minutes, 4.25ml of ammonia water (28wt%) was added dropwise to the solution obtained above, and the obtained mixture was aged in an oven at 60-90° C. for 2 hours. The suspension was centrifuged, and the collected solid was washed 3 times with ultrapure water and ethanol;

In step three, the solid obtained in step two is dried in an oven at 60-90° C. for 15 hours to obtain the carrier NiAl ₉ . Then 10 mmol of Al(NO ₃ ) ₂ ·9H ₂ O was used to prepare pure Al support, and the product was boehmite (AlOOH). Introduce NiAl ₉ into boehmite flakes to obtain catalyst precursor NiAl ₉ -LDHs/AlOOH;

Step 4: Weigh 300 mg of catalyst precursor NiAl ₉ -LDHs/AlOOH in 10 ml of ultrapure water, then add H ₂ PtCl ₆ solution under continuous magnetic stirring; after soaking for 1 hour, quickly add 5 ml of sodium borohydride (0.572 mol L ^-1 ) and sodium hydroxide (0.252mol·L ^-1 ) suspension mixed aqueous solution. After continuous stirring for 1 h, it was centrifuged, and the collected solid was washed 4 times with ultrapure water and ethanol; the obtained solid was dried in an oven at 60-90° C. for 12 h, and the Pt loading was 0.2%.

For detection, the Pt _0.2 NiAl ₉ -LDHs/AlOOH obtained in the above-mentioned Example 5 was placed on a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and gas chromatography was used for quantitative analysis. The reaction results show that Pt _0.2 NiAl ₉ -LDHs/AlOOH can partially decompose 380ppm formaldehyde in 5 hours, the conversion rate is 70%, and the catalyst remains stable without deactivation within 24 hours.

Embodiment six:

Step 1, weigh 20.5g polyethylene glycol (PEG400), add 100ml cyclohexane, mix by magnetic stirring, then quickly add 20ml containing 1mmolNi(NO ₃ ) ₂ 6H ₂ O and 9mmolAl(NO ₃ ) ₂ 9H ₂ O solution;

Step 2: After 10 minutes, 4.25ml of ammonia water (28wt%) was added dropwise to the solution obtained above, and the obtained mixture was aged in an oven at 60-90° C. for 2 hours. The suspension was centrifuged, and the collected solid was washed 3 times with ultrapure water and ethanol;

In step three, the solid obtained in step two is dried in an oven at 60-90° C. for 15 hours to obtain the carrier NiAl ₉ . Then 10 mmol of Al(NO ₃ ) ₂ ·9H ₂ O was used to prepare pure Al support, and the product was boehmite (AlOOH). Introduce NiAl ₉ into boehmite flakes to obtain catalyst precursor NiAl ₉ -LDHs/AlOOH;

Step 4: Weigh 300 mg of catalyst precursor NiAl ₉ -LDHs/AlOOH in 10 ml of ultrapure water, then add H ₂ PtCl ₆ solution under continuous magnetic stirring; after soaking for 1 hour, quickly add 5 ml of sodium borohydride (0.572 mol L ^-1 ) and sodium hydroxide (0.252mol·L ^-1 ) suspension mixed aqueous solution. After continuous stirring for 1 h, it was centrifuged, and the collected solid was washed 4 times with ultrapure water and ethanol; the obtained solid was dried in an oven at 60-90° C. for 12 h, and the Pt loading was 0.1%.

For detection, the Pt _0.1 NiAl ₉ -LDHs/AlOOH obtained in the above-mentioned Example 5 was placed on a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and gas chromatography was used for quantitative analysis. The reaction results show that Pt _0.1 NiAl ₉ -LDHs/AlOOH can partially decompose 620ppm formaldehyde in 5 hours, the conversion rate is 83%, and the catalyst remains stable within 24 hours without deactivation.

Comparative example 1:

Step 1, weigh 20.5g polyethylene glycol (PEG400), add 100ml cyclohexane, mix by magnetic stirring, then quickly add 20ml containing 1mmolMg(NO ₃ ) ₂ 6H ₂ O and 9mmolAl(NO ₃ ) ₂ 9H ₂ O solution;

Step 2: After 10 minutes, 4.25ml of ammonia water (28wt%) was added dropwise to the solution obtained above, and the obtained mixture was aged in an oven at 60-90° C. for 2 hours. The suspension was centrifuged, and the collected solid was washed 3 times with ultrapure water and ethanol;

In step three, the solid obtained in step two is dried in an oven at 60-90° C. for 15 hours to obtain the carrier MgAl ₉ . Then use 10mmol Al(NO ₃ ) ₂ ·9H ₂ O to prepare pure Al carrier, and the product is boehmite (AlOOH), which is ground into powder. Mix MgAl ₉ with boehmite powder to obtain catalyst precursor MgAl ₉ -LDHs/AlOOH;

Step 4: Weigh 300 mg of catalyst precursor MgAl ₉ -LDHs/AlOOH in 10 mL ultrapure water, then add H ₂ PtCl ₆ solution under continuous magnetic stirring; after immersion for 1 hour, quickly add 5 ml of sodium borohydride (0.572 mol L ^{- 1} ) and sodium hydroxide (0.252mol·L ^-1 ) suspension mixed aqueous solution. After continuous stirring for 1 h, centrifuge, wash the collected solid with ultrapure water and ethanol 4 times; dry in an oven at 60-90° C. for 12 h, and the loading of Pt is 0.2%.

For detection, the Pt _0.2 MgAl ₉ -LDHs/AlOOH obtained in the above comparative example 1 was placed in a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and gas chromatography was used for quantitative analysis. The reaction results show that Pt _0.2 MgAl ₉ -LDHs/AlOOH can only completely decompose 360ppm formaldehyde in 6 hours, and the catalyst remains stable without deactivation in 24 hours.

Comparative example 2:

Step 1, weigh 20.5g polyethylene glycol (PEG400), add 100ml cyclohexane, mix by magnetic stirring, then quickly add 20ml containing 1mmol Ca(NO ₃ ) ₂ ·6H ₂ O and 9mmolAl(NO ₃ ) ₂ ·9H ₂ O solution;

Step 2: After 10 minutes, 4.25 mL of ammonia water (28 wt %) was added dropwise to the obtained solution, and the obtained mixture was aged in an oven at 60-90° C. for 2 hours. The suspension was centrifuged, and the collected solid was washed 3 times with ultrapure water and ethanol;

In step three, the solid obtained in step two is dried in an oven at 60-90° C. for 15 hours to obtain the carrier CaAl ₉ . Then use 10mmol Al(NO ₃ ) ₂ ·9H ₂ O to prepare pure Al carrier, and the product is boehmite (AlOOH), which is ground into powder. Mix CaAl ₉ with boehmite powder to obtain the catalyst precursor CaAl ₉ -LDHs/AlOOH;

Step 4: Weigh 300 mg of catalyst precursor CaAl ₉ -LDHs/AlOOH into 10 mL of ultrapure water, then add H ₂ PtCl ₆ solution under continuous magnetic stirring; after soaking for 1 h, quickly add 5 mL of sodium borohydride (0.572 mol L ^-1 ) and sodium hydroxide (0.252mol·L ^-1 ) suspension mixed aqueous solution. After continuous stirring for 1 h, centrifuge, wash the collected solid with ultrapure water and ethanol 4 times; dry in an oven at 60-90°C for 12 h, and the loading of Pt is 0.2%;

For detection, the Pt _0.2 CaAl ₉ -LDHs/AlOOH obtained in the above comparison 2 was placed in a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and gas chromatography was used for quantitative analysis. The reaction results showed that Pt _0.2 CaAl ₉ -LDHs/AlOOH could completely decompose only 420ppm formaldehyde within 8 hours, and the catalyst remained stable without deactivation within 24 hours.

Comparative example 3: (without loading Pt NPs)

Step 1, weigh 20.5g polyethylene glycol (PEG400), add 100ml cyclohexane, mix by magnetic stirring, then quickly add 20ml containing 1mmolNi(NO ₃ ) ₂ 6H ₂ O and 9mmolAl(NO ₃ ) ₂ 9H ₂ O solution;

Step 2: After 10 minutes, 4.25 mL of ammonia water (28 wt %) was added dropwise to the obtained solution, and the obtained mixture was aged in an oven at 60-90° C. for 2 hours. The suspension was centrifuged, and the collected solid was washed with ultrapure water and ethanol for 3 times;

In step three, the solid obtained in step two is dried in an oven at 60-90° C. for 15 hours to obtain the carrier NiAl ₉ . Then 10 mmol of Al(NO ₃ ) ₂ ·9H ₂ O was used to prepare pure Al support, and the product was boehmite (AlOOH). Introduce NiAl ₉ into boehmite flakes to obtain NiAl ₉ -LDHs/AlOOH;

Step 4, place the above-mentioned NiAl ₉ -LDHs/AlOOH on a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and use gas chromatography for quantitative analysis. The reaction results show that NiAl ₉ -LDHs/AlOOH can partially decompose 450ppm formaldehyde in 5h with a conversion rate of 76%, and the catalyst remains stable within 24h without deactivation.

Comparative Example 4: (No loaded Pt NPs, no AlOOH)

Step 1, weigh 20.5g polyethylene glycol (PEG400), add 100ml cyclohexane, mix by magnetic stirring, then quickly add 20ml containing 1mmolNi(NO ₃ ) ₂ 6H ₂ O and 9mmolAl(NO ₃ ) ₂ 9H ₂ O solution;

Step 2: After 10 minutes, 4.25ml of ammonia water (28wt%) was added dropwise to the solution obtained above, and the obtained mixture was aged in an oven at 60-90° C. for 2 hours. The suspension was centrifuged, and the collected solid was washed 3 times with ultrapure water and ethanol;

Step 3, drying the solid obtained in Step 2 in an oven at 60-90°C for 15 hours to obtain the carrier NiAl ₉ ;

For detection, the NiAl ₉ -LDHs obtained in Comparative Example 4 above was placed on a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and gas chromatography was used for quantitative analysis. The reaction results show that NiAl ₉ -LDHs can only partially decompose 170ppm formaldehyde, the conversion rate is 50%, and the catalyst remains stable within 24h without deactivation.

Comparative example 5: (using Al ₂ O ₃ as carrier)

Step 1, measure 50ml concentration and be the aluminum nitrate solution of 0.5mol/L, add 12g urea to make urea and Al3+ mol ratio be 8:1 in above-mentioned solution, transfer above-mentioned solution in the 100ml reactor, under sealed condition Reaction at 160°C for 8 hours, the obtained precipitate was filtered and dried in an oven at 60°C for 24 hours without washing, and the obtained precipitate was crushed and then calcined at 600°C for 4 hours to obtain an Al ₂ O ₃ carrier;

Step 2, weigh 300 mg of the carrier obtained in step (1) into 10 mL of ultrapure water, and then add H ₂ PtCl ₆ solution under continuous magnetic stirring; after soaking for 1 hour, quickly add 5 ml of sodium borohydride (0.572 ^mol·L ) and sodium hydroxide (0.252mol·L ^-1 ) suspension mixed aqueous solution. After continuous stirring for 1 h, centrifuge, wash the collected solid with ultrapure water and ethanol 4 times; dry the obtained solid in an oven at 60°C for 12 h, and the loading of Pt is 0.2%;

For detection, the Pt _0.2 Al ₂ O ₃ obtained in Comparative Example 5 above was placed on a micro-tubular catalyst evaluation device for catalytic oxidation of formaldehyde, and gas chromatography was used for quantitative analysis. The reaction results show that Pt _0.2 Al ₂ O ₃ can partially decompose 500ppm formaldehyde with a conversion rate of 80%, and the catalyst remains stable within 24 hours without deactivation.

The above-mentioned preferred implementation mode should be regarded as an illustration of the implementation mode of the scheme of this application, and any technical deduction, replacement, improvement, etc. that are similar to, similar to, or based on the scheme of this application should be regarded as the scope of protection of this patent.

Claims (9)

1. A catalyst for catalytic formaldehyde at room temperature, characterized in that it comprises an active component and a carrier, wherein the active component comprises platinum nanoparticles, and the carrier is a mixture of nickel-aluminum composite hydrotalcite and boehmite. 2. A catalyst for catalyzing formaldehyde at room temperature according to claim 1, characterized in that the loading of the platinum nanoparticles on the carrier is greater than 0wt% and less than 1wt%. 3. The catalyst for catalyzing formaldehyde at room temperature according to claim 1 or 2, characterized in that the loading of the platinum nanoparticles on the carrier is 0.2wt%. 4. A catalyst for catalyzing formaldehyde at room temperature according to claim 1, characterized in that the molar ratio of nickel and aluminum in the nickel-aluminum composite hydrotalcite is 1:9 or 1:7 or 1:5. 5. a preparation method of room temperature catalytic formaldehyde catalyst, for preparing the catalyst of a kind of room temperature catalytic formaldehyde as described in claim 1-4 arbitrary, it is characterized in that, comprises the steps: Step 1, dissolving nickel nitrate hexahydrate and aluminum nitrate nonahydrate in a mixed solution of polyethylene glycol and cyclohexane; In step 2, add ammonia water dropwise to the solution obtained in step 1, then age, centrifuge, wash, and dry, so as to obtain a nickel-aluminum composite oxide carrier; Step 3, preparing boehmite with aluminum nitrate nonahydrate, cutting it into pieces, and introducing the nickel-aluminum composite oxide carrier into the boehmite to obtain a catalyst precursor; Step 4, immersing the catalyst precursor in the chloroplatinic acid solution, and draining; In step five, the product obtained in step four is reduced with sodium borohydride reducing agent, then stirred, centrifuged, washed and dried to obtain a catalyst. 6. the preparation method of a kind of room temperature catalytic formaldehyde catalyst according to claim 5 is characterized in that, in step 2, the massfraction of described ammoniacal liquor is 25-28wt%. 7. the preparation method of a kind of room temperature catalytic formaldehyde catalyst as claimed in claim 5 is characterized in that: the drying temperature in the described step 2 is 60-90 ℃, and the drying time is 15h; The temperature is 60-90℃, and the drying time is 12h. 8. the preparation method of a kind of room temperature catalytic formaldehyde catalyst as claimed in claim 5 is characterized in that: in step 3, the step of cutting boehmite into sheets is specifically: cutting boehmite into a size of 10mm x 10mm x 2mm sheet. 9 . The method for preparing a formaldehyde catalyst at room temperature as claimed in claim 5 , wherein in step 5, the concentration of the sodium borohydride reducing agent is 0.572 mol·L ⁻¹ .

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