AU2021103205A4

AU2021103205A4 - A Supported Mesoporous Palladium Catalyst Used For Catalytic Removal Of Low Concentration Of Benzene At Normal Pressure And Its Preparation Method

Info

Publication number: AU2021103205A4
Application number: AU2021103205A
Authority: AU
Inventors: Zhaojie JIAO; Mengna LAN; Hongmei Xie; Xuejiao ZHAI; Xianming ZHANG; Yue Zhao; Guilin ZHOU
Original assignee: Chongqing Technology And Business University Technology Development Co Ltd; Chongqing University; Chongqing Technology and Business University
Current assignee: Chongqing Technology And Business University Technology Development Co Ltd; Chongqing Technology and Business University
Priority date: 2021-06-08
Filing date: 2021-06-08
Publication date: 2021-07-29
Anticipated expiration: 2029-06-08

Abstract

of Descriptions The present invention discloses a supported mesoporous palladium catalyst used for catalytic removal of low concentration of benzene at normal pressure, wherein, the active components of the said catalyst are noble metal palladium, and the carrier is SiO2 with a mesoporous structure. In addition, the present invention discloses a method for preparing the said catalyst, which takes advantage of the supported catalyst to reduce the application amount of the noble metal, and uses the carrier as a dispersant or support of the active components of the catalyst to increase the effective surface of the catalyst, and thus provides a proper pore structure which can guarantee sufficient mechanical strength and thermal stability. The said catalyst of the present invention loads noble metal palladium on a solid carrier, and thus prepares a supported palladium catalyst, which can not only maintain the catalytic activity, but also reduce the application amount of palladium on the one hand; and on the other hand, can enhance the activity and selectivity of the catalyst through improving the loading capacity of active components contained in the supported palladium catalyst.

Description

Descriptions

A Supported Mesoporous Palladium Catalyst Used for Catalytic Removal of Low Concentration of Benzene at Normal Pressure and Its Preparation Method

Technical Field

[0001] The present invention relates to a catalyst for catalytic hydrogenation of benzene in gas phase, particularly to a supported mesoporous palladium catalyst used for catalytic removal of low concentration of benzene at normal pressure and its preparation method.

Background Technology

[0002] There are a great many of pollution sources of benzene, besides motor vehicle exhaust, emissions from the petrochemical industry also constitute an important source. The motor octane number of benzene is relatively high. In the event that there is lack of high-octane gasoline components, the gasoline would have retained relatively high content of aromatic hydrocarbons and benzene. Due to the structure of benzene is stable, it is hard to generate oxidation reaction, and thus results in incomplete combustion of internal combustion engine of motor vehicle during operation, so that makes the benzene be discharged into the atmosphere with exhaust gas and thus pollutes the atmospheric environment; accordingly, gas stations and tank wagon loading and unloading stations also can be deemed as a pollution source of benzene. In addition, excessive discharge of waste water and waste gas by petrochemical companies is another main source which would cause benzene pollution accidents in the environment. For instance, there is a large amount of benzene is contained in the "Triphenyl" products produced by petrochemical companies, and the waste gas generated by shoemaking, paint, and printing industries, etc. Furthermore, accidents occurred during the storage and transportation process of benzene, such as overturning, and the breakage or leakage of container, etc., also can cause serious pollution.

[0003] As we all know, benzene is a hazardous substance, which may cause various hazards. On the one hand, benzene is recognized as a strong carcinogen, coupled with its high volatility, it is easy to spread when exposed to the air, which would endanger public health. The World Health Organization has identified benzene as a strong carcinogen, which may have effects of mutagenesis, teratogenesis and carcinogenesis on organisms (referred to herein as "three hazards"), also can damage bone marrow and hematopoietic function. On the other hand, remaining excessive content of benzene in gasoline is harmful. Although the motor octane number of benzene is relatively high, some studies suggested that benzene has poor blending performance, which is opposite to most aromatic hydrocarbons. Thus, for the purpose of making gasoline have better blending performance, the content of benzene contained in gasoline should not be too high. Moreover, excessive content of benzene remained in gasoline also would have an adverse impact on gasoline combustion to certain extent, which can produce a tendency of increasing carbon deposits. Therefore, for the last few years, countries in the world have attached great importance to the harmful effect of benzene. Most of them have formulated content standard of benzene remained in the atmosphere. For example, the European Union has implemented the standard that the annual average concentration limit of benzene in the

Descriptions

atmosphere should be controlled at 5 g/m3 from December 1, 2000, which should be at 1 g/m3 from January 1, 2006. In addition, there are requirements on the benzene content in gasoline proposed worldwide, meanwhile, the limitation of benzene content tends to be more rigorous. Nowadays, the GB IV standard for motor gasoline limits the volume content of benzene to being not more than 1.0%. With the implementation of the American Clean Fuel Regulations (The standard for emission of motor vehicle exhaust and toxicant: Mobile Source AirToxics II), refiners in US have reduced the benzene volume content of gasoline from the current level of 1.0% to 0.62% (annual mean value) prior to 2011.

[0004] Nowadays, simple physical separation methods have been incapable of satisfying the requirements of controlling benzene content, thus, the most effective method is to take advantage of chemical conversion method to reduce benzene. Benzene has a special and stable aromatic ring structure itself, and the stable structure of which is hard to be destroyed even by means of catalytic oxidation (combustion) methods. Furthermore, such stable benzene ring structure can be destroyed by catalytic hydrogenation based upon selecting a proper catalyst, and thus make it be converted into a low-toxic or non-toxic compound. In recent years, quite a lot of relevant studies on benzene hydrogenation catalysts have been carried out by domestic and foreign researchers, however, these studies still focus on the design and development of catalytic materials. Currently, the benzene hydrogenation catalysts adopted mainly consist of precious metal catalysts, including Pt, Pd, Ru and Rh, etc. (Shi Xiangyu. Application Research of Nickel Series Benzene Hydrogenation Catalysts[J]. Journal of Chemical Industry and Engineering, 2013, 34 (2) :5-7; Liu Dawei. Research on Catalytic Performance of Benzene Hydrogenation Catalyst Pd/MCM-41[J]. Journal of Chemical Industry and Engineering, 2012, 33 (2): 59-60; Liu Youpeng, Sun Guofang, Gao Peng, et al. Progress in Ru-based Catalysts for Partial Hydrogenation of Benzene to Cyclohexene [J].Industrial Catalysis, 2015(4):266-271; Bagdaulet,Kenjaliev, Bolysbek,et al.Hydrogenation of Benzene at Presence of Rhodium Support Catalyst[J]. Chemistry and Chemical Engineering: English Edition, 2013(2):154-158). Compared with non-precious metal catalysts, it has various good catalytic performances including high activity (the conversion rate >99%), and good selectivity (>99%), etc., which is of great interest to researchers. Although precious metal catalysts have many advantages, the high price become a hindrance to the application of precious metal catalysts in the catalytic removal of benzene. For this reason, it is necessary to develop a catalyst that can address the problem of the high pricing of existing catalysts, and which can not only maintain the catalytic activity of the catalyst, but also may reduce the application amount of catalyst. In addition, for the catalytic hydrogenation of benzene process, the current research mostly adopts the intermittent high-pressure liquid phase benzene hydrogenation process. However, the utilization rate of hydrogen participating in the liquid phase benzene hydrogenation reaction is relatively low, and the reactants and the catalyst are not easy to be separated, as well as the continuous production can not be accomplished, so that result in low production efficiency. If high conversion rate and yield are required, it must be equipped with a secondary reactor, which has high energy consumption. With respect to current research on gas phase benzene hydrogenation, most of which conducts catalytic reaction at the high pressure between 0.5 and 3.0 MPa. For instance, the new nickel series catalysts studied by Wang Jinli can realize the gas phase hydrogenation of benzene at the pressure of 0.6 MPa (Wang Jinli, Study on New Nickel Series Catalyst for Benzene

Descriptions

Hydrogenation in Gas Phase [D]. East China University of Science and Technology, 2014.). In addition, the pressure conditions required in the application of precious metal catalysts are higher. For example, the findings proposed by Liu Ming, i.e., Pt/A 20 3 catalyst can realize gas phase hydrogenation of benzene at the pressure of 3.1MPa (Liu Ming. Research of Pt/A 20 3 Catalyst for Benzene Hydrogenation in Gas Phase [J]. Journal of Chemical Industry and Engineering, 2008, 29(2): 7-10.). Thus, it is necessary to realize the exploration which can carry out catalytic reaction under conventional conditions.

Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a supported mesoporous palladium catalyst used for catalytic removal of low concentration of benzene in gas phase and its preparation method, which has good catalytic activity for benzene hydrogenation at low temperature and normal pressure.

[0006] For the purpose of achieving the aforesaid objective, the present invention provides following technical scheme:

[0007] 1. A supported mesoporous palladium catalyst used for catalytic removal of low concentration of benzene at normal pressure, wherein, the active components of the said catalyst are metal palladium, and the carrier is Si02 with a mesoporous structure.

[0008] Preferably, the said Si02 with a mesoporous structure is mesoporous KIT-6.

[0009] Preferably, the loading capacity of the metal palladium contained in the said catalyst is 1%~10%.

[0010] Preferably, the loading capacity of noble metal palladium in the catalyst is 5%.

[0011] 2. A method for preparing the catalyst, and the preparation steps of which are as follows:

[0012] 1) Impregnation: impregnate the carrier in the solution of palladium salt, and then dry the solvent by distillation and conduct drying treatment, and thus obtain a dry material;

[0013] 2) Roasting: roast the dry material obtained from step 1) in a muffle furnace;

[0014] 3) Reduction: conduct reduction of the roasted product under hydrogen atmosphere, and thus obtain the said supported mesoporous palladium catalyst.

[0015] Preferably, in step 1), the said palladium salt is palladium chloride, and the solvent used to the said palladium salt is hydrochloric acid.

[0016] Preferably, the specific parameters of the roasting process conducted in the said step 2) are: heat up the dry material to the temperature of 450-550°C at a heating rate of 5°C/min in a muffle furnace at room temperature, and then roast it at the constant temperature of 450-550°C for 2-4 hours.

[0017] Preferably, the said step 3 is conducted at the temperature of 180~220°C.

[0018] The beneficial effects of the present invention consist of:

[0019] 1) taking advantage of the supported catalyst to reduce the application amount of the noble metal, and using the carrier as a dispersant or support of the active components of the catalyst to increase the effective surface of the catalyst, and thus providing a proper pore structure which can guarantee sufficient mechanical strength and thermal stability. The said

Descriptions

catalyst of the present invention loads noble metal palladium on a solid carrier, and thus prepares a supported palladium catalyst, which can not only maintain the catalytic activity, but also reduce the application amount of palladium on the one hand; and on the other hand, can enhance the activity and selectivity of the catalyst through improving the loading capacity of active components contained in the supported palladium catalyst.

[0020] 2) The supported mesoporous palladium catalyst of the present invention has a developed mesoporous structure, which provides superior conditions for the adsorption and activation of molecules of reactants, and provides superior conditions for the diffusion and migration of molecules of reactants and products in the catalyst either. The catalyst disclosed in the present invention facilitates benzene hydrogenation to be conducted under normal pressure conditions, which can reduce the requirements for reaction equipment, and thus reduce the reaction cost. In addition, the supported mesoporous palladium catalyst of the present invention manifested good catalytic hydrogenation activity of benzene at high reaction air velocity (12000mL-h-1-g-1), low reaction temperature (<220°C), and normal pressure, which has a good catalytic removal performance of benzene in gas phase at low temperature and normal pressure;

[0021] 3) The present invention prepares supported mesoporous palladium catalyst through palladium salt by means of impregnation method, which adopts simple process and mild conditions, as well as is easy to control, and has good reproducibility.

Brief Description of the Drawings

[0022] In order to make the objectives, technical scheme and beneficial effects of the present invention clearer, the present invention provides following drawings:

[0023] Figure 1 is the XRD spectrogram indicates the supported mesoporous palladium catalysts with different loading capacities;

[0024] Figure 2 is the N 2 adsorption-desorption isothermal curve of the supported mesoporous palladium catalysts with different loading capacities;

[0025] Figure 3 is the curve graph indicates the BJH pore size distribution of the supported mesoporous palladium catalysts with different loading capacities.

Detailed Description of the Presently Preferred Embodiments

[0026] The text below will describe the preferred embodiments of the present invention in detail in conjunction with the accompanying drawings. Any experimental method which do not specify specific conditions in the embodiments shall be in accordance with conventional conditions or follow the conditions recommended by the manufacturer.

[0027] Embodiment 1

[0028] The active components of the supported mesoporous palladium catalyst of this embodiment are noble metal palladium, and the carrier is mesoporous KIT-6. Wherein, the preparation method for the supported mesoporous palladium catalyst of this embodiment consists of following steps:

Descriptions

[0029] 1) Impregnation: impregnate the carrier in a hydrochloric acid solution made of palladium chloride (the mixture ratio of aqueous hydrochloric acid solution is 1:3), and then dry the hydrochloric acid solvent by distillation at the temperature of 50-70°C with constant stirring, and thus obtain the raw material, after that, dry the obtained raw material at a constant temperature of -70°C for 24 hours, and thus obtain the dry material;

[0030] 2) Roasting: heat up the dry material obtained from the step 1) to the temperature of 450 550°C at a heating rate of 5°C/min in a muffle furnace at room temperature, and then roast it at the constant temperature of 450-550°C for 2-4 hours.

[0031] 3) Reduction: conduct reduction of the roasted product under hydrogen atmosphere, then, heat up it to the temperature of 180-220°C at a heating rate of10°C/min in a microtubular fixed bed reactor, after that, complete reduction at the constant temperature of 180220°C for 0.5-1.5 hours, wherein, the hydrogen used is high-purity hydrogen, and the gas flow is 13-17 mL/min, and thus obtain the supported mesoporous palladium catalyst (hereinafter referred to as Pd/KIT-6).

[0032] The Pd/KIT-6 with palladium metal loading capacities of 1%, 3%, 5%, and 7% were prepared according to the aforesaid steps.

[0033] The synthesis method for the carrier mesoporous KIT-6 used in this embodiment see following documents: Guilin Zhou, Hai Lan, Hui Wang, et al. Catalytic combustion of PVOCs on MnOx catalysts[J]. Journal of Molecular Catalysis AChemical, 2014, 393(18):279-288;

[0034] Catalytic activity test

[0035] Use the Pd/KIT-6 catalyst prepared in the aforesaid embodiment to complete the catalytic removal of low-concentration benzene, and conduct the evaluation of activity of the catalyst; wherein, the evaluation of activity of the catalyst shall be conducted in a microtubular fixed bed reactor with an inner diameter of 8 mm at normal pressure, and there is a thermocouple is built in the reactor, and there is a micro-reactor is equipped in the heating furnace; in addition, the percentage by volume of benzene waste gas shall be 3.47% benzene and 96.53% hydrogen; and the specific operation steps are as follows:

[0036] Measured 50-60 mg of catalyst into the reaction tube of the microtubular fixed bed reactor, and then, heated up to the reaction temperature, after that, injected the benzene waste gas with the said components, and removed the benzene at that reaction temperature and at the air velocity of reaction gas of 12000mL-h-'g- under constant temperature (the hydrogen flow is controlled by a flow meter), then, detected the residual benzene content in the exhaust gas on-line by a GC-7980 gas chromatograph with a hydrogen flame detector, wherein, the detection conditions are: the temperature of the detector should be 210°C, the temperature of injection port should be 150°C, and the oven temperature should be constant at 70°C.

[0037] The conversion rates of catalytic hydrogenation of benzene of the supported palladium catalysts with different loading capacities and different structural carriers of the embodiment obtained through the aforesaid evaluation experiment of catalyst activity are as shown in Table 1:

[0038] Table 1 Conversion rate test data of Pd/KIT-6 used in catalytic hydrogenation reaction of

Descriptions

benzene

[0039]

Catalyst Loading Capacity of Reaction Temperature Removal Rate of Palladium /°C Benzene

% Pd/KIT-6 Catalyst 120 3.99 140 7.06

[0040]

1% 160 11.43 180 16.38 200 21.65 220 23.00 3% 120 17.92 140 34.42 160 58.48 180 84.58 200 96.36 5% 120 37.45 140 83.09 160 92.83 180 99.67 7% 120 44.87 140 81.57 160 96.90 180 99.79 Pd/SiO 2 -mos catalyst 5% 120 26.59 140 53.50 160 79.29 180 96.53 200 97.55 Pd/white carbon black 120 14.62 catalyst 140 28.89

[0041]

5% 160 48.88 180 67.01 200 81.21 220 81.85

Descriptions

Pd/quartz sand 5% 120 3.17 catalyst 140 7.05 160 12.34 180 16.01 200 19.31

[0042] It can be seen from the aforesaid conversion rates of catalytic hydrogenation of benzene that the supported mesoporous palladium catalysts of the embodiment manifested the activity of catalytic hydrogenation of benzene at high reaction air velocity (12000mL-h-Ig-I) and low reaction temperature (<220); meanwhile, the loading capacity of noble metal palladium has a great influence on the activity of catalytic hydrogenation of benzene. For example: if the loading capacity of the Pd/KIT-6 catalyst is 5%, the conversion rate of catalytic hydrogenation of benzene would reach 96.60% at the reaction temperature of 180°C; however, if the loading capacity of the Pd/KIT-6 catalyst is 1%, the conversion rate of catalytic hydrogenation of benzene just can reach 23% at the reaction temperature of 220°C; and if the loading capacity of the Pd/KIT-6 catalyst is 3%, the conversion rate of catalytic hydrogenation of benzene can reach 96.37% at the reaction temperature of 200°C; furthermore, if the loading capacity of the Pd/KIT-6 catalyst is 7%, the conversion rate of catalytic hydrogenation of benzene can reach 99.80% at the reaction temperature of 18°C; Although, the conversion rate of catalytic hydrogenation of benzene of the Pd/KIT-6 catalyst with the 7% of loading capacity is higher than that of the Pd/KIT-6 catalyst with the 5% of loading capacity, the difference between them is not large. In addition, from an economic perspective, it can be concluded that the Pd/KIT-6 catalyst with the 5% of loading capacity is more proper for the catalytic hydrogenation and removal of benzene. According to the aforesaid results, it also can be seen that the mesoporous structures with different carriers would have a certain effect on the activity of the supported mesoporous palladium catalyst for catalytic hydrogenation of benzene, wherein, the activity of Pd/KIT-6 catalyst for catalytic hydrogenation of benzene is the highest. Comparing the supported mesoporous palladium catalyst with the non-mesoporous supported Pd/quartz sand catalyst, it can be seen that the mesoporous structure of the carrier is very conducive to the catalytic hydrogenation reaction of benzene. Moreover, the aforesaid catalytic hydrogenation and removal reactions of benzene are all completed at normal pressure, however, for the existing noble metal catalysts used for catalytic hydrogenation of benzene, the removal rate of benzene approximate to 95% can only be realized at high pressure generally (see bibliography, Xiong Jianping, Wang Baohe, Zhu Jing, et al. Preparation and Characterization of New cyclohexene Ru-B/ZnO-ZrO_2 Catalyst Made from Hydrogenation of Benzene [J]. Journal of Chemical Industry and Engineering, 2013, 30( 1 ): 20-26. The bibliography recorded that only if the reaction pressure reaches 4.0 MPa conversion rate of benzene can reach 74%). It can be seen that the supported mesoporous palladium catalyst prepared by the impregnation method of the present invention has good activity of catalytic hydrogenation of benzene at normal pressure and low temperature, which is an efficient catalyst used for catalytic removal of low concentration of benzene, and can achieve the purpose of removal of benzene at a lower reaction temperature.

[0043] Conduct X-ray diffraction analysis to the Pd/KIT-6 catalysts with different loading

Descriptions

capacities of the embodiment; wherein, the X-ray diffraction analysis was conducted on the Rigaku D/Max-2500/PC X-ray diffractometer manufactured by the Rigaku Corporation; and Cu Ka was the X-ray source, X = 1.5418 A, and used Ni filter, in addition, the tube pressure was kV, the tube current was 200mA, and the scanning rate was3/min, the scan range was 20-90°, as well as the scanning step-length was 0.02°.

[0044] The XRD spectrogram of the Pd/K1T-6 catalysts with different loading capacities of the embodiment obtained through X-ray diffraction analysis is as shown in figure 1. It can be seen from figure 1, the prepared Pd/KIT-6 catalysts mainly detected Pd and SiO 2 phase, and the XRD diffraction peak intensity of the Pd phase detected by the Pd/KIT-6 catalyst is very strong and the peak width is narrow, which indicates that the Pd phase existed in the Pd/KIT-6 catalyst has high crystallinity. In addition, the XRD diffraction peak intensity of all SiO 2 phases detected by the Pd/KIT-6 catalyst is weak and the peak width is narrow, which indicates that the crystallinity of the SiO 2 phases existed in the Pd/KIT-6 catalyst is poor, and are mainly existed in the form of highly dispersed state or amorphous state, furthermore, the presence of species in the form of highly dispersed state has laid the material foundation for the high catalytic activity of the catalyst. Based upon comparing the XRD spectrogram of Pd/KIT-6 catalysts with different loading capacities, it can be seen that as the loading capacity of Pd increases, the XRD diffraction peak intensity of the Pd phase becomes stronger. However, compared with the 5% of loading capacity, the 7% of loading capacity loading has fairly faint enhancement effect on the XRD diffraction peak. Thus, the 5% of loading capacity applied in the embodiment is the optimal loading capacity.

[0045] The adsorption-desorption analysis to the Pd/KIT-6 catalysts with different loading capacities of the embodiment was conducted after being reduced for 1 hour at the temperature of 200°C and at the hydrogen flow of 25mL/min, and then measured isotherm curve of N 2 adsorption-desorption. The N2 adsorption-desorption via the ASAP 3020 type (Mike Company, U.S.A.) automatic analyzer at the temperature of -196°C. Prior to testing, the samples should be vacuum degassed at the temperature of 200°C for 8 hours, after that, calculated the specific surface area of the samples by the BET equation based on the relative pressure P/PO appeared on the adsorption curve.

[0046] The N 2 adsorption-desorption isothermal curves of the Pd/KIT-6 catalysts with different loading capacities of the embodiment are as shown in figure 2, and the corresponding curve graph of the BJH pore size distribution is as shown in figure 3. It can be seen from figure 2 that the N 2 adsorption-desorption isothermal curves of the Pd/KIT-6 catalysts with different loading capacities of the embodiment all have obvious hysteresis loops, and the adsorption types are all typical type IV adsorption isotherms. P/P0 was selected between 0.45 and 1.0, and the H1-type hysteresis loop caused by capillary condensation appeared on isothermal curves of all four catalysts, which indicated that the preparation process of the catalysts could replicate the mesoporous structure of KIT-6 template well, and thus obtained the Pd/KIT-6 catalyst with developed mesoporous structure, in addition, the specific surface area of the catalyst was approximate to 550m 2/g. Thus, the prepared Pd/KIT-6 catalyst of the present invention has a developed mesoporous structure, which can provide superior conditions for the adsorption and activation of molecules of reactant, and also can provide superior conditions for the diffusion and

R

Descriptions

migration of molecules of reactant and products in the catalyst, so that laid the foundation for the high catalytic activity of the catalyst. It can be seen from figure 3 that as the loading capacity increases, the pore size of the catalyst would be enlarged, which may have impact on the activity of the catalyst. In view of that the catalytic hydrogenation effect of 5% or 7% of loading capacities is equivalent, and the catalyst structure of 5% of loading capacities is more conducive to the activity of catalytic hydrogenation, the optimal loading capacity of the embodiment is selected as 5%.

[0047] In the present invention, the types of the carrier and the palladium salt, the specific process parameters of drying and roasting, etc., can be appropriately adjusted according to the requirements of the impregnation method, and all of them can achieve the purpose of the present invention.

[0048] Finally, it is to be noted that the aforesaid preferred embodiments are only used to illustrate the technical scheme of the present invention rather than imposing restrictions on it. Although the present invention has been described in detail through the aforesaid preferred embodiments, for those skilled in the art should understand that any variation in terms of forms or details can be done without departing from the scope defined by the claims of the present invention.

EDITORIAL NOTE 2021103205

There are 8 claims only.

Claims

Claims 1. A supported mesoporous palladium catalyst used for catalytic removal of low concentration of benzene at normal pressure, characterized in that the active components of the said catalyst are metal palladium, and the carrier is SiO 2 with a mesoporous structure. 2. The said catalyst according to Claim 1, characterized in that the said SiO 2 with a mesoporous structure is mesoporous KIT-6. 3. The said catalyst according to Claim 1, characterized in that the loading capacity of the metal palladium contained in the said catalyst is 1010%. 4. The said catalyst according to Claim 3, characterized in that the loading capacity of the metal palladium contained in the said catalyst is 5%. 5. A method for preparing the said catalyst of any one of Claims 1-5, characterized in that the preparation steps are as follows:

1) Impregnation: impregnate the carrier in the solution of palladium salt, and then dry the solvent by distillation and conduct drying treatment, and thus obtain a dry material; 2) Roasting: roast the dry material obtained from step 1) in a muffle furnace; 3) Reduction: conduct reduction of the roasted product under hydrogen atmosphere, and thus obtain the said supported mesoporous palladium catalyst. 6. The said preparation method according to Claim 5, characterized in that the said palladium salt is palladium chloride, and the solvent used to the said palladium salt is hydrochloric acid. 7. The said preparation method according to Claim 5, characterized in that the specific parameters of the roasting process conducted in the said step 2) are: heat up the dry material to the temperature of 450-550°C at a heating rate of 5°C/min in a muffle furnace at room temperature, and then roast it at the constant temperature of 450-550°C for 2-4 hours. 8. The said preparation method according to Claim 5, characterized in that the said step 3 is conducted at the temperature of 180220°C.