CN111974382A

CN111974382A - Application of low-temperature CO oxidation or ADN decomposition platinum-based catalyst

Info

Publication number: CN111974382A
Application number: CN201910427727.0A
Authority: CN
Inventors: 王晓东; 陈洋; 林坚; 吕飞; 夏连根; 张涛
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2019-05-22
Filing date: 2019-05-22
Publication date: 2020-11-24
Anticipated expiration: 2039-05-22
Also published as: CN111974382B

Abstract

The invention relates to an alumina-supported platinum (Pt) catalyst, and a preparation method and application thereof. In particular to a composite catalyst which takes a single component Pt as an active center and takes inert alumina as a carrier. Wherein the platinum content is 0.5-5% of the total mass of the catalyst, and the platinum is highly dispersed on the alumina in the form of clusters, and the cluster size is 0.5-3.0 nm. The catalyst is used for the oxidation elimination of carbon monoxide (CO) in an ultralow temperature environment (minus 80-0 ℃) and the purification of a hydrogen source used by a proton exchange membrane fuel cell power generation system. In particular, the catalyst of the present invention is also suitable for catalytically decomposing Ammonium Dinitramide (ADN) at low temperatures. The catalyst provided by the invention has the characteristics of simple preparation method, high selectivity and high stability, and has a good industrial application prospect.

Description

Application of low-temperature CO oxidation or ADN decomposition platinum-based catalyst

Technical Field

The invention relates to an alumina-supported platinum cluster catalyst and preparation and application thereof, wherein platinum is highly dispersed on alumina in a cluster form of 0.5-3.0 nm, and the platinum is used as a unique active center to show higher catalytic performance in the oxidation of ultralow temperature carbon monoxide (CO) and the selective elimination of trace CO in a hydrogen source. The catalyst achieves Ammonium Dinitramide (ADN) decomposition at low temperature.

Background

CO oxidation is one of the most important and most widely studied catalytic processes. Wide CO source, high toxicity and wide explosion limit (12.5-74%), so it is environmental friendly and CO is widely used₂The laser, the CO gas mask, the industrial application, the elimination of CO in the closed space, the development of new energy resources (fuel cell technology) and the like have very important application values. This reaction is particularly important for the catalytic conversion of automobile exhaust gases. However, the oxidation temperature of CO involved in the conversion process is often higher than 200 ℃, and most pollutants in the current automobile exhaust are discharged within 30s of cold start, so that the development of a catalyst with low temperature and high activity is needed. The U.S. department of energy has established a goal to reduce automotive processing temperatures below 150 ℃. The method aims to synthesize the CO oxidation catalyst with low temperature and high activity and has important practical application value. Meanwhile, with the development and popularization of new energy electric vehicles, the demand on power batteries is increasing day by day, and hydrogen energy fuel batteries have the advantages of wide sources, cleanness, no pollution, long one-time endurance and the like, and are competitive high points in the technical field of the future automobile industry. At present, the hydrogen source is mainly from industrial reforming process, wherein a small amount of CO can poison the electrode catalyst of the fuel cell, and the selective oxidation elimination of the visible CO also has important significance for the development and the improvement of the performance of the fuel cell.

Platinum-based catalysts, which are the most widely used catalysts, have an important role both in basic research and in industrial applications, and consume 37-50% of the Pt world reserves annually for exhaust gas purification (catalysis.2017, 7, 58). Researchers believe that high dispersion of Pt particles is the key to achieving high activity, but the catalyst prepared by the traditional wet chemical method has the complete CO conversion temperature higher than 60 ℃ and poor low-temperature activity. The preparation of the low-temperature CO oxidation catalyst with high dispersion, uniform size and high activity through the optimization of the preparation method and the modulation of the catalyst structure is still one of the hot spots and difficulties of the current catalytic research.

Selectxo was first developed and commercialized by Engelhard in 1963^TM(Pt/Al₂O₃) The catalyst is used for purifying CO in hydrogen in ammonia synthesis industry, and then Pt/Al is used₂O₃The catalysts have been extensively studied. Pt/Al prepared by the sol-gel method (appl. Catal. B: environmental.2002,37:17-25.) by Manasilp et Al₂O₃The catalyst shows 2% Pt/Al₂O₃The catalyst has CO converting rate up to 80% and selectivity up to 50% at 170 deg.c. Alumina-supported single-component Pt-based catalysts have a high optimum reaction temperature, and therefore attempts have been made to add a second component to activate oxygen, thereby achieving CO oxidation under low temperature conditions. Studies have shown that the addition of the transition metals Fe (science 2010,328,1141-1144.), Ni (J.Am.chem.Soc.2011,133, 1978-1986), Co (Angew.chem.int.Ed.2007,46, 734- ₂O₃The catalytic activity is promoted. In addition, Minemura et Al (Chem Commun.2005,1429-1431.) study found alkali metal ion addition to Pt/Al₂O₃The catalytic activity also has a remarkable promoting effect, but simultaneously brings about the problems of catalyst repeatability, corrosion to equipment in the practical application process and the like. While reducing noble metal loading to monoatomic dispersion increases metal utilization, it does not achieve oxidative elimination of CO at room temperature (Nature chemistry 2011,3, 634-641.).

Therefore, attention has been directed to single metal active-center catalysts, primarily to inert support-supported Pt-based catalysts. Zhu et al (nat. commun.2017,8:15291) found that complete CO conversion can be achieved at 67 ℃ by making the BN surface vacancy rich and then modulating the electronic properties of the Pt nanoparticles at the interface. In SiO₂On supported Pt-based catalysts, studies have shown that (science.2010,328,1141-1144; appl.Catal.B-environ.1996,10, 245-. Peterson et Al (nat. Commun.2014,5: 4885-one 5885) found La modified Al₂O₃The carrier is beneficial to improving the catalytic activity and stability of Pt, but the complete CO conversion temperature is still higher than 150 ℃. Recently, Newton et Al (nat. Commun.2015,6:8675- ₂O₃Catalyst for adsorbing CO and O₂The Pt carbonate has low-temperature CO oxidation activity when being formed, but has poor room-temperature activity on the whole, and the carbonate can be completely decomposed by needing higher temperature. Therefore, no matter the Pt is modified by adding alkali metal and transition metal, or the carrier is modified by electronic regulation and doping, the complete oxidation of CO on the single Pt catalyst loaded by the inert carrier at room temperature or even ultralow temperature can not be realized.

At present, a propellant with high performance, environmental protection, no toxicity and low cost has wide application prospects in the fields of military affairs and aerospace, ADN (ammonium dinitramide) as one of novel high-energy green propellants represents a new research direction and development trend of space chemistry propulsion technology, and compared with a conventional AP (ammonium perchlorate) based propellant, the propellant has the advantages of high energy density, environmental protection, no toxicity, low characteristic signal, good safety performance, good thermal decomposition performance and the like, thereby causing high attention of people and becoming a research hotspot in the field of propellants in recent years. (researches on catalysis and surface modification of warrior ammonium dinitramide [ D ]. Nanjing: Nanjing university of physical Engineers, 2006.) ADN catalytic decomposition technology is one of the key technologies, and simultaneously faces some difficulties, so that the popularization and the use of the novel environment-friendly propellant are determined. The invention reports the preparation of the inert alumina-supported platinum catalyst for the first time, and investigates the low-temperature CO (selective oxidation) oxidation elimination and ADN catalytic decomposition performance.

Disclosure of Invention

The invention aims to provide an inert carrier Al₂O₃The supported Pt catalyst has Pt highly dispersed on a carrier in a cluster form of 0.5-3.0 nm, and is used as the only catalyst for CO oxidation, trace CO elimination in a hydrogen source and ADN catalytic decomposition in room temperature and extremely low temperature environmentAn active center.

In order to achieve the purpose, the invention adopts the technical scheme that:

a CO oxidation catalyst in room temperature and extremely low temperature environment is composed of alumina and noble metal Pt, wherein the content of Pt is 0.1-5% of the total mass of the catalyst. The noble metal Pt is highly dispersed on the alumina.

The catalyst is prepared by adopting a colloid-deposition method, wherein a glycol solution of a Pt precursor is stirred and slowly added into a glycol solution of alumina, the volume ratio of the two solutions is 1:1, the pH value is adjusted by adding an alkali solution, the mixture is stirred and reacted, the mixture is kept stand and aged for 1h, and the mixture is subjected to suction filtration, washing and drying at 80 ℃ for 1 h.

The Pt precursor is preferably a chloroplatinic acid solution of Pt.

The carrier is alumina.

The required precipitation and aging temperature is preferably 70-80 ℃; the pH of the solution is preferably 8-10; the drying temperature of the catalyst is preferably 80 ℃ and the drying time is preferably 12 hours.

The catalyst can be used for CO oxidation elimination in a low-temperature environment, CO complete conversion can be realized at-20 ℃, and CO in a hydrogen-rich atmosphere is selectively oxidized into CO within the temperature range of 0-200 DEG C ₂。

The catalyst is used for catalytic decomposition of ADN, realizes ADN decomposition at 25 ℃, and has good low-temperature activity.

The method for testing the CO oxidation activity of the catalyst comprises the following steps:

will contain 0.1 to 5 vol.% CO, 0.5 to 20 vol.% O₂At a space velocity of 1X 10⁴～1×10⁵mL g_cat.^-1h^-1Introducing the mixture into a fixed bed reactor filled with a catalyst, and measuring the activity of the catalyst for CO oxidation from-80 ℃ temperature programming under normal pressure.

The rapid decomposition test method for ADN of the catalyst of the present invention is as follows:

injecting 100 mu LADN propellant on the catalyst in the reactor at the low temperature of 25 ℃, decomposing ADN fuel, recording the change data of temperature and pressure along with time, injecting again after the temperature is reduced to 25 ℃, carrying out reaction for 4 times, and counting the decomposition process, thereby evaluating the stability of the catalyst.

Compared with the prior art, the invention has the substantial characteristics that:

1. the catalyst prepared by the invention has the characteristic of high dispersion of the active component, and the obtained Pt cluster has controllable size and uniform dispersion, thereby being beneficial to improving the activity of the catalyst and improving the utilization rate of the active component Pt. The content of the noble metal Pt is reduced, so that the cost of the catalyst is reduced.

2. The catalyst uses inert alumina as a support, with Pt as the only active center.

3. The catalyst has excellent low-temperature catalytic oxidation performance, and is firstly in Pt/Al₂O₃The method realizes the complete oxidation of CO at the temperature of-20 ℃, realizes the CO conversion rate of 100% in the hydrogen-rich atmosphere at the temperature of 0-200 ℃, and has important significance for the oxidation elimination of trace CO in the automobile exhaust and the hydrogen source under the actual condition.

4. The catalyst has good activity in the catalytic decomposition of ADN aqueous solution, realizes the ADN catalytic decomposition at 25 ℃, and has good low-temperature activity.

Drawings

FIG. 1 is a comparison of the CO oxidation activity of the catalysts prepared in examples 1, 2, 7 of the present invention with the commercial catalyst in comparative example 1.

FIG. 2 shows the catalysts prepared in examples 1, 7, 9 and 10 of the present invention and the standard Au/Al in comparative example 2₂O₃CO oxidation activity of the catalysts was compared.

FIG. 3 is a TOF comparison of catalysts prepared in examples 1 and 7 of the present invention with commercial catalysts in comparative examples 1 and 2.

FIG. 4 shows the catalysts prepared in examples 1 and 7 of the present invention and commercial Pt/Al catalyst in comparative example 1₂O₃The CO selective oxidation reactivity of the catalyst.

FIG. 5 shows the stability of the selective CO oxidation reaction at 80 ℃ for the catalyst prepared in example 7 of the present invention.

FIG. 6 is a graph of CO conversion as a function of oxygen concentration for a catalyst prepared in example 7 of the present invention as shown in FIG. 6A and CO ₂Alternative fig. 6B.

FIG. 7 shows commercial Pt/Al in example 7 of the present invention and comparative example 1₂O₃And (5) carrying out XRD result on the catalyst.

FIG. 8 shows commercial Pt/Al in examples 1, 2, and 7 of the present invention and comparative example 1₂O₃HAADF-STEM pictures and particle size statistics of the catalyst.

FIG. 9 is a graph of 2.5 wt% Pt/Al prepared according to example 7 of the present invention₂O₃The catalyst is used for ADN catalytic decomposition at 25 ℃.

Detailed Description

The following examples are intended to illustrate the invention in more detail and are not intended to limit the scope of the invention.

Example 1:

dissolving 1g of chloroplatinic acid in 50ml of ethylene glycol solution, adding the solution into a three-neck flask under the protection of Ar gas, adding NaOH (50ml,0.5M) into an alcoholic solution of the chloroplatinic acid (1g), stirring to obtain a transparent yellow Pt colloidal solution, heating to 140 ℃ for 3 hours, and carrying away water and organic by-products in the system through Ar gas and condensation reflux. Obtaining a dark brown uniform Pt cluster colloidal solution with the size of 0.5-1.3 nm, wherein the concentration of Pt in the sol is 3.7 mg/ml.

Example 2:

except for example 1 where NaOH (50ml,0.3M) was added, the other conditions and materials were the same as in example 1, and the Pt cluster sol size was 2.7. + -. 0.6 nm. The test conditions for the catalyst used for low temperature CO oxidation were consistent with example 15.

Example 3:

except for the difference from example 1 in that the heating temperature was 160 ℃ and the mass of chloroplatinic acid was 0.27g, the other conditions and materials were the same as in example 1, and the size of the Pt cluster sol was 0.5. + -. 0.3 nm.

Example 4:

the difference from the example 1 is that platinum tetraammine nitrate is dissolved in ethylene glycol solution, and other conditions and materials are the same as the example 1, so that the Pt cluster colloidal solution which is dark brown and has the size of 0.5-1.3 nm is obtained.

Example 5: the difference from the embodiment 1 is that the platinum tetraammine hydroxide is dissolved in the ethylene glycol solution, and other conditions and materials are the same as the embodiment 1, so as to obtain the Pt cluster colloidal solution with dark brown color and the size of 0.5-1.3 nm.

Example 6:

different from the embodiment 1, the method is to dissolve platinum acetylacetonate in ethylene glycol solution, and other conditions and materials are the same as those of the embodiment 1, so as to obtain the dark brown Pt cluster colloidal solution with the size of 0.5-1.3 nm.

Example 7:

dispersing 1g of gamma-alumina carrier in 100mL of glycol solution, stirring in 80 ℃ water bath, taking 6.76mL of the Pt cluster colloidal solution of 3.7mg/mL of example 1, adding 100mL of glycol for dilution, slowly adding the Pt cluster colloidal solution into the carrier alcohol solution under strong stirring, adjusting the pH value to 9.5 by 0.1M NaOH, stirring for 3h at 80 ℃, standing for 1h, carrying out suction filtration, washing by hot ultrapure water, and drying for 16h in an oven at 80 ℃ to obtain 2.5 wt.% of Pt/gamma-Al ₂O₃The results of the catalyst used for the very low temperature carbon monoxide oxidation evaluation are shown in fig. 1, and the test results show that 2.5 wt.% Pt/γ -Al prepared by this method₂O₃The catalyst has excellent low-temperature performance and realizes complete CO conversion at-20 ℃. The test conditions were: the amount of catalyst used was 100mg, and the gas volume composition was 1 vol.% CO +1 vol.% O₂+ He, total gas flow 30ml/min (STP), mass space velocity 1.8X 10⁴mL g_cat ^-1h^-1The catalyst was pre-tested at 10 vol.% H₂Reducing at 200 ℃ for 0.5h under the atmosphere of/He, purging with He to reduce the temperature to room temperature, keeping the temperature of each temperature point to be detected constant for 20min, sampling, detecting the gas composition at the outlet of the reactor by adopting a chromatograph, and calculating the conversion rate.

Example 8:

different from example 7 in that 1.35mL of 3.7mg/mL Pt cluster colloid solution of example 1 was used, and other conditions and materials were the same as example 7, 0.5 wt.% Pt/Al was obtained₂O₃A catalyst.

Example 9:

different from example 7 in that 2.16mL of the 3.7mg/mL Pt cluster colloid solution of example 1 was used, and other conditions and materials were the same as example 7, 0.8 wt.% Pt/Al was obtained₂O₃A catalyst. Catalyst and process for preparing sameThe test conditions for low temperature CO oxidation were consistent with example 15.

Example 10:

in contrast to example 7, taking 13.5mL of the 3.7mg/mL Pt cluster colloid solution of example 1, the other conditions and materials were the same as in example 7, 5 wt.% Pt/Al was obtained ₂O₃A catalyst. The test conditions for the catalyst used for low temperature CO oxidation were consistent with example 15.

Example 11:

in contrast to example 7, the pH of the solution was adjusted to 13 using 0.5M NaOH, and the other conditions and materials were the same as in example 7, to give 2.5 wt.% Pt/Al₂O₃A catalyst.

Example 12:

in contrast to example 7, in which no NaOH was added after loading and the pH was 7, the other conditions and materials were the same as in example 7, giving 2.5 wt.% Pt/Al₂O₃A catalyst.

Example 13:

in contrast to example 7, 0.1M sodium carbonate (Na) was used₂CO₃) The pH of the solution was adjusted to 9.5 and the other conditions and materials were the same as in example 7 to give 2.5 wt.% Pt/Al₂O₃A catalyst.

Example 14:

in contrast to example 7, 0.1M aqueous ammonia was used to adjust the pH of the solution to 9.5, and the other conditions and materials were the same as in example 7, to give 2.5 wt.% Pt/Al₂O₃A catalyst.

Comparative example 1:

commercial 5 wt% Pt/Al₂O₃(Sigma-Aldrich) catalyst. The results of the selective oxidation reaction evaluation of the catalyst for low temperature carbon monoxide oxidation and trace CO in hydrogen source are shown in fig. 1 and 4, and the test results show that commercial 5 wt% Pt/Al₂O₃The catalyst was run to complete CO conversion at 140 deg.C, and we prepared 2.5 wt% Pt/Al from example 7₂O₃The catalyst CO complete conversion temperature was 160 ℃ lower than the commercial catalyst, indicating commercial 5 wt% Pt/Al ₂O₃The catalyst activity is poor. FIG. 1 test conditions and test strips of example 15The pieces are identical. The test conditions of FIG. 4 are in accordance with those of example 17.

Comparative example 2:

standard 0.7 wt% Au/Al for purchase₂O₃(Haruta Company) catalyst. The evaluation result of the catalyst used for the low-temperature carbon monoxide oxidation reaction is shown in figure 2, and the test result shows that the standard 0.7 wt% Au/Al₂O₃(Haruta Company) the catalyst achieved complete conversion of CO at 50 deg.C, while our example 9 produced a similar loading of 0.8 wt% Pt/Al₂O₃The catalyst can realize complete conversion of CO at 40 ℃, which shows that the low-temperature catalytic activity of the catalyst is equivalent to that of the Au catalyst. The test conditions were identical to those of example 15.

Example 15:

and (3) carrying out CO oxidation activity test on the catalyst by adopting a fixed bed micro-reverse evaluation device. The test conditions were: the amount of catalyst used was 100mg, and the gas volume composition was 1 vol.% CO +1 vol.% O₂+ He, total gas flow 30ml/min (STP), mass space velocity 1.8X 10⁴mL g_cat ^-1h^-1The catalyst was pre-tested at 10 vol.% H₂Reducing at 200 ℃ for 0.5h under the atmosphere of/He, purging with He to reduce the temperature to room temperature, keeping the temperature of each temperature point to be detected constant for 20min, sampling, detecting the gas composition at the outlet of the reactor by adopting a chromatograph, and calculating the conversion rate.

The CO conversion was calculated as follows:

CO Conversion(％)＝{([CO]in–[CO]out)/[CO]in}×100％

wherein: [ CO ] in, [ CO ] out are the CO chromatographic peak areas of the feed and the reactor outlet, respectively.

Example 16: investigating the influence of noble metal Pt loading on CO oxidation activity

100mg of 0.5 to 5 wt% Pt/Al of example 7, example 9, example 10 and comparative example 2 was taken₂O₃And 0.7 wt% Au/Al₂O₃The catalysts are respectively arranged in a quartz reaction tube, and before the reaction, the catalyst is in 10 vol% H₂Reducing for 0.5h at 200 ℃ in a/He atmosphere, blowing the He to the room temperature, and using the pretreated catalyst for carbon monoxide oxidation reaction evaluation. The results are shown in figure 2 of the drawings,the test result shows that the low-temperature activity of the catalyst is improved by increasing the Pt loading amount, the complete CO conversion at the temperature of minus 60 ℃ is realized when the Pt loading amount is 5 wt%, and the catalyst has good low-temperature CO oxidation performance.

Example 17: investigating the carbon monoxide selective oxidation performance of the catalyst

100mg of the catalysts of example 7 and comparative example 1 were taken in a quartz reaction tube, respectively, with a gas volume composition of 1 vol.% CO +1 vol.% O₂+40vol％H₂+ He, total gas flow 33.3ml/min (STP), mass space velocity 2.0X 10⁴mL g_cat ^-1h^-1The catalyst was pre-tested at 10 vol.% H₂Reducing for 0.5h at 200 ℃ under the atmosphere of/He, purging with He to reduce the temperature to room temperature, and evaluating the carbon monoxide selective oxidation reaction of the pretreated catalyst. The result is shown in FIG. 4, and the test result shows that the catalyst prepared by the method can realize the complete CO conversion within the temperature range of 0-200 ℃, the CO conversion rate of the commercial catalyst is 100% within the temperature range of 140-220 ℃, and the commercial catalyst has a narrow complete CO conversion temperature range and a high reaction temperature.

Example 18: investigating CO/O in the reaction atmosphere₂Effect of the ratio on the Activity

100mg of 2.5 wt% Pt/Al of example 7 were taken₂O₃Catalyst in quartz reactor tube, catalyst was pre-tested at 10 vol.% H₂Reducing the catalyst for 0.5h at 200 ℃ under the atmosphere of/He, purging the He to reduce the temperature to room temperature, and evaluating the carbon monoxide selective oxidation reaction of the pretreated catalyst under the condition of CO/O₂The ratio is 0.8-2, He is balance gas, the total flow rate of reaction gas is 33.3ml/min, the evaluation result is shown in FIG. 4, when CO/O₂In ratio 2, CO₂The selectivity is 100% in the temperature range of-30 to 200 ℃, which shows that the 2.5 wt% Pt/Al prepared by the method₂O₃The catalyst has good catalytic activity and selectivity.

Example 19: evaluation of catalyst stability

100mg of 2.5 wt% Pt/Al of example 7 were taken₂O₃The catalyst is placed in a quartz reaction tube, and before the reaction, the catalyst is in 10 vol% H₂Reducing for 0.5h at 200 ℃ in a/He atmosphere, and blowing by HeAnd (3) cooling to room temperature, and using the pretreated catalyst for evaluation of carbon monoxide selective oxidation reaction, wherein the stability test result is shown in figure 5, and the activity of the catalyst is not obviously changed within 20h, which shows that the catalyst has good stability.

Example 20: ADN catalytic decomposition test 2.5 wt% Pt/Al example 7 into a reactor at 25 deg.C ₂O₃Injecting 100 mu LADN propellant on the catalyst, decomposing ADN fuel, recording the change data of temperature and pressure along with time, injecting again after the temperature is reduced to 25 ℃, reacting for 4 times, counting the decomposition process, and evaluating the stability of the catalyst. The test result is shown in fig. 9, and it can be seen from the figure that the catalyst realizes ADN decomposition at a low temperature of 25 ℃, indicating that the catalyst has good low-temperature activity.

Claims

1. The application of a platinum-based catalyst for low-temperature CO oxidation or ADN decomposition is characterized in that:

the platinum-based catalyst is used for CO oxidation: the complete conversion of CO can be realized at a low temperature of more than-20 ℃, the preferred catalysis temperature is-20-100 ℃, and the more preferred catalysis temperature is-20-60 ℃;

alternatively, platinum-based catalysts are used for the selective oxidation of CO: and subjecting the mixture to a hydrogen-rich atmosphere at a temperature of 0-200 deg.C (hydrogen-rich atmosphere means 40 vol% H₂And above hydrogen-containing atmosphere) CO is selectively eliminated, the preferred catalytic temperature is 0-120 ℃, and the more preferred catalytic temperature is 0-90 ℃;

alternatively, platinum-based catalysts are used for the catalytic decomposition of Ammonium Dinitramide (ADN): the decomposition of ADN can be realized at 25 ℃ or above, the preferred catalytic temperature is 25-200 ℃, and the more preferred catalytic temperature is 25-100 ℃.

2. Use according to claim 1, characterized in that: the platinum-based catalyst is composed of alumina and noble metal platinum, the alumina is used as a carrier, the platinum is used as a unique active component, and the platinum content accounts for 0.5-5% of the total mass of the catalyst.

3. The catalyst according to claim 1 or 2, wherein: platinum is uniformly dispersed on the alumina carrier in the form of clusters, and the cluster size is 0.5-3.0 nm, and more preferably 1.2-2.0 nm.

4. The use of the catalyst according to claim 1, wherein the platinum-based catalyst is prepared by a colloid-deposition two-step process, which comprises the following steps:

(1) reduction of Pt precursor by ethylene glycol in inert atmosphere: dissolving a Pt precursor in an ethylene glycol solution, adding alkali to adjust the pH value to 10-13, stirring and reacting at 120-160 ℃, and heating for 1-3 hours to obtain a dark brown Pt sol solution;

(2) dispersing alumina into ethylene glycol, slowly adding a Pt sol solution, adjusting the volume ratio of the two solutions to be 1: 1-1: 2.5, adding an alkali solution to adjust the pH value to be 8-10, stirring for reaction, standing and aging for 1-3 h, performing suction filtration, washing, drying at 60-80 ℃ for 12-24 h, and performing reduction treatment to obtain the target catalyst.

5. Use of a catalyst according to claim 4, wherein: the Pt precursor is chloroplatinic acid, tetramine platinum nitrate, tetramine platinum hydroxide or acetylacetone platinum; the concentration of Pt in the Pt sol solution is 0.1-5 mg/ml;

the alkali solution is 0.1-0.5M sodium hydroxide, 0.1-1.0M sodium carbonate or 5-18M ammonia solution.

6. Use of a catalyst according to claim 4, wherein: the catalyst is subjected to 1-100 vol% of H₂and/He, reducing for 0.5-3 h at 200-400 ℃, wherein the gas flow rate is 20-100 ml/min.