WO2022213493A1 - 一种高效催化甘油氧化制备甘油酸的催化剂、其制备方法及用途 - Google Patents

一种高效催化甘油氧化制备甘油酸的催化剂、其制备方法及用途 Download PDF

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WO2022213493A1
WO2022213493A1 PCT/CN2021/103966 CN2021103966W WO2022213493A1 WO 2022213493 A1 WO2022213493 A1 WO 2022213493A1 CN 2021103966 W CN2021103966 W CN 2021103966W WO 2022213493 A1 WO2022213493 A1 WO 2022213493A1
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cacotio
catalyst
preparation
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glycerol
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安哲
何静
黄泽宇
朱彦儒
宋红艳
王文龙
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北京化工大学
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali- or alkaline earth metals
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
    • C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
    • C07C51/23—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of oxygen-containing groups to carboxyl groups

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  • the invention relates to the fields of chemical engineering and catalysts, in particular to a catalyst for efficiently catalyzing glycerol oxidation to prepare glyceric acid and a preparation method thereof.
  • Biomass energy is an ideal renewable alternative resource.
  • Glycerol is a by-product produced in the transesterification process of biodiesel (100Kg of glycerol is produced per ton of biodiesel produced), but its downstream conversion capacity is insufficient, resulting in excess capacity. Therefore, it is of great significance to catalyze the conversion of glycerol into high value-added products.
  • Glyceric acid is a multifunctional high-value fine chemical that can be used in the pharmaceutical and food industries, and is also an important intermediate.
  • Existing catalysts for oxidizing glycerol to prepare glyceric acid are mainly divided into homogeneous catalysis and heterogeneous catalysis.
  • heterogeneous catalysis has always been favored by researchers due to its easy operation in reaction control, simple process flow and greenness.
  • the target of heterogeneous catalytic oxidation of glycerol has become a research hotspot.
  • problems in the research reports such as low catalytic activity, poor selectivity, limited reaction conditions (addition of alkali), catalyst deactivation and so on.
  • the preparation of glyceric acid from glycerol needs to go through two reaction steps, the first step is the oxidative dehydrogenation of glycerol to generate aldehyde, and the second step is to insert OH* species into glyceraldehyde to generate glyceric acid.
  • the oxidative dehydrogenation process of alcohols mainly uses oxygen as the oxidant.
  • the hydrogen cleavage of the primary hydroxyl group of glycerol and ⁇ -position C-H combines with an oxygen atom generated by the activation of oxygen to form water and removes water.
  • the oxidation of aldehyde involves the separation of the aldehyde group and the ⁇ -position C-H.
  • Activation of hydrogen, activation of oxygen in aqueous solution generates OH* species insertion.
  • the efficient preparation of glycerol from glycerol requires selective activation of primary hydroxyl groups, inhibition of deep oxidation, and avoidance of C-C bond cleavage. See Science 2010 VOL330, P74 for OH* (hydroxyl reactive species).
  • Pt-based bimetallic catalysts were used to catalyze the selective oxidation of glycerol to glyceric acid under liquid phase conditions.
  • the researchers added non-precious metals Co, Cu, and Sn to the Pt-based catalysts to obtain better performance.
  • Microwave irradiation prepared highly dispersed PtCo bimetallic nanoparticles. Compared with Pt/RGO and Co/RGO, PtCo/RGO significantly improved the oxidation performance of glycerol, glycerol conversion (70.2%) and glyceric acid selectivity ( 85.9%) were significantly higher than those of single-metal Pt/RGO and Co/RGO (J. Catalysis Today, 2017, 298: 234–240).
  • the present invention provides a catalyst for efficiently catalyzing the oxidation of glycerol to prepare glyceric acid, the catalyst has the synergistic effect of Pt single atom and Pt cluster, and has more excellent catalytic performance.
  • the invention provides a catalyst for efficiently catalyzing the oxidation of glycerol to prepare glyceric acid, the catalyst is PtCo/CaCoTiO 3 , and the XRD characteristic diagram of the carrier CaCoTiO 3 is 23.39°, 33.32°, 39.29°, 41.11°, 59.54° and 69.97° at 2 ⁇ .
  • the characteristic diffraction peaks of perovskite structure appear at °, which are respectively assigned to the (200), (022), (-113), (-222), (400), (-224), (440) crystal planes in CaCoTiO 3 ;
  • CaCoTiO 3 as a carrier has a monoclinic crystal structure JCPDS34-0394; and Pt and Co exist in the form of nanoparticles with an average particle size of 2nm ⁇ 0.2nm.
  • the present invention further provides a preparation method of the aforementioned catalyst, comprising the following steps:
  • the CaCoTiO3 composite oxide carrier was synthesized by sol-gel method
  • the Co/CaCoTiO 3 was sealed with deionized water and poured into a container, and then in the atmosphere of magnetic stirring and inert gas, the H 2 PtCl 6 aqueous solution was added dropwise to the container, and the reaction was carried out at room temperature and vigorous stirring, After the solid product is repeatedly washed after the reaction, the solid product is dried under vacuum conditions to obtain a PtCo/CaCoTiO 3 catalyst.
  • step 1) take Ca(NO 3 ) 2 ⁇ 4H 2 O and Co(NO 3 ) 2 ⁇ 6H 2 O to prepare a mixed solution, stir and mix evenly, then add C 6 H 8 O 7 ⁇ H 2 O (citric acid monohydrate) continues to stir to obtain solution A;
  • the solution B is added dropwise to the solution A, and after the dropwise addition is completed, the pH value of the mixed solution is adjusted to 5-7, and the wet gel is formed by continuing to keep stirring;
  • the wet gel is dried to obtain a dry gel, and the dry gel is ground and calcined to remove citric acid, and is then calcined again after being lowered to room temperature to obtain a CaCoTiO 3 composite oxide.
  • the molar ratio of the Ca(NO 3 ) 2 ⁇ 4H 2 O and the Co(NO 3 ) 2 ⁇ 6H 2 O is 1:(0.1-0.3); preferably, the molar ratio is 1 : 0.2.
  • the amount of C 6 H 8 O 7 ⁇ H 2 O (citric acid monohydrate) added is 1-5 times the mole number of metal ions, and the metal ions are Ca ions, Co ions and Ti ions; preferably Preferably, the added amount is 1-2 times the mole number of metal ions.
  • step 1) after adding C 6 H 8 O 7 ⁇ H 2 O, continue stirring for 0.1-1 h.
  • step 1) the volume ratio of the tetrabutyl titanate to the absolute ethanol is 1:(1-3).
  • step 1) the tetrabutyl titanate and the absolute ethanol are mixed uniformly, and the stirring time is 0.1-2 h to obtain a clear and transparent solution B.
  • step 1) the pH value is adjusted to 6 with ammonia water.
  • step 1) after adjusting the pH value, the mixture is stirred at a constant temperature of 30-50° C. for 3-6 h.
  • step 1) the wet gel is dried at 60-90° C. for 24-72 hours to form a dry gel.
  • step 1) the xerogel is ground into powder, and then heated from room temperature to 260-350° C. in a muffle furnace for 1-5 hours, wherein the heating rate is 2° C./min.
  • the heating rate was 2°C/min to remove citric acid.
  • the temperature is raised to 300°C.
  • step 1) the secondary calcination is that the calcined solid that has been lowered to room temperature is then raised from room temperature to 550-650° C. and maintained for 1.5-3 h, and the heating rate is 5° C./min.
  • step 2) the reduction of the carrier is to lay the solid powder of the CaCoTiO composite oxide on the bottom of the porcelain boat, and then put the porcelain boat into the central constant temperature zone of the quartz tube of the tube furnace, and then place the In a closed state, use a vacuum pump to evacuate and then slowly introduce reducing gas until the pressure value reaches normal pressure, keep the gas flow rate at 40ml/min, and gradually heat up the tube furnace at a heating rate of 10°C/min.
  • the center of the quartz tube is kept at a constant temperature
  • the temperature of the zone reaches 550-650 °C, it is kept for 1.5-3 h, and then cooled to room temperature to obtain a Co/CaCoTiO 3 composite oxide.
  • the temperature of the constant temperature zone reaches 600°C and the holding time is 2h.
  • step 3 the Co/CaCoTiO composite oxide is liquid - sealed and poured into a container with deionized water, and H is added dropwise to the container under stirring at 600-800 rpm and nitrogen protection PtCl 6 aqueous solution, vigorously stirred at room temperature for 15-72 h, the ionic equation of the displacement reaction that occurs is as follows:
  • the solid product is repeatedly washed with deionized water, centrifuged after each washing, and the solid product is washed at least once with absolute ethanol after the washing is completed. , and then the solid product after the washing treatment is vacuum-dried at 50-70° C. for 0.1-48 h to obtain a PtCo/CaCoTiO 3 catalyst.
  • the temperature of vacuum drying is 60°C and the time is 24h.
  • the vigorous stirring is 700 revolutions/min.
  • the present invention further provides the use of the aforementioned catalyst, especially the use in the reaction of glycerol oxidation to prepare glyceric acid.
  • the conversion rate of glycerol can reach 99.0%
  • the selectivity of glycerol can reach 72.0%
  • the yield of glyceric acid product can reach 71.1%.
  • the catalyst of the present invention can achieve precise control of the catalyst structure of the coexistence of Pt single atoms and Pt clusters through the coordination of raw materials and preparation conditions in the preparation process;
  • the conversion rate of glycerol is 99.0%
  • the selectivity of glyceric acid reaches 72.0%
  • the yield of glyceric acid product reaches 71.1%.
  • Fig. 1 is the process schematic diagram of embodiment 1 and comparative example 1, comparative example 2 preparing catalyst;
  • Fig. 2 is the HADDF-STEM electron microscope image of the catalyst prepared in Example 1 and Comparative Example 1 and Comparative Example 2;
  • Figure 3 is a supplementary electron microscope diagram of the catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2;
  • Fig. 4 is the propanol adsorption/desorption test curve of the catalyst prepared by Example 1 and Comparative Example 1 and Comparative Example 2
  • Fig. 5 is the simulation diagram of the propanol adsorption configuration of the catalyst prepared in Example 1 and Comparative Example 1 and Comparative Example 2;
  • FIG. 6 is the XRD characterization diagram of the carrier composite oxide and the products corresponding to the preparation steps.
  • Example 1 Sample-Pt 1+C Co/CaCoTiO 3 catalyst (Pt 1+C Co/rCCT, where Co/rCCT is Co particles obtained by reduction in perovskite)
  • the second sample is that Pt exists in the catalyst in the form of single atoms and clusters in Co particles, and the preparation method of the catalyst includes the following steps:
  • solution B In another container, take an equal volume of 6.807g of tetrabutyl titanate and mix it with 6.8mL of absolute ethanol to obtain solution B, which is clear and transparent;
  • the solution B was added dropwise to the solution A, and after the dropwise addition was completed, the pH value of the mixed solution was adjusted to 6, and the wet gel was formed by continuing to keep stirring for 5 hours at 40°C;
  • the wet gel was dried in an oven at 80°C for 48 hours to form a dry gel.
  • the temperature was raised from room temperature to 300°C at a heating rate of 2°C/min in a muffle furnace and then heated to 300°C. Hold for 2h, then drop to room temperature, and then increase the temperature from room temperature to 600°C at a heating rate of 5°C/min and hold for 2h to obtain the CaCoTiO 3 composite oxide carrier;
  • the XRD pattern of the carrier CaCoTiO3 has characteristic diffraction peaks of perovskite structure at 2 ⁇ of 23.39°, 33.32°, 39.29°, 41.11°, 59.54° and 69.97°, which are respectively attributed to (200), (022), (-113), (-222), (400), (-224), (440) crystal planes;
  • CaCoTiO3 as a carrier is a monoclinic crystal structure JCPDS34-0394;
  • the reduction of the carrier is to spread the solid powder of the CaCoTiO composite oxide carrier on the bottom of the porcelain boat, and then put the porcelain boat into the constant temperature zone in the center of the quartz tube of the tube furnace, and evacuated with a vacuum pump in a closed state. Then slowly introduce hydrogen until the pressure value reaches normal pressure, keep the gas flow rate at 40ml/min, and gradually heat up the tube furnace at a heating rate of 10°C/min. When the temperature of the constant temperature zone in the center of the quartz tube reaches 600°C, keep 2h, and then cooled to room temperature to obtain Co/CaCoTiO 3 ;
  • the solid product is repeatedly washed three times with deionized water, centrifuged after each washing, and the solid product is washed once with absolute ethanol after the washing is completed. , and then the washed solid product was vacuum-dried at 60°C for 24 hours to obtain a PtCo/CaCoTiO 3 catalyst; the solid powder of the PtCo/CaCoTiO 3 catalyst was spread on the bottom of the porcelain boat, and then the porcelain boat was Put the quartz tube in the central constant temperature zone of the tube furnace, evacuate it with a vacuum pump in a closed state, and then slowly introduce hydrogen until the pressure value reaches normal pressure, keep the gas flow rate at 40ml/min, and gradually increase the temperature at a rate of 10°C/min.
  • the tube furnace was heated up, and when the temperature of the constant temperature zone in the center of the quartz tube reached 600 °C, it was kept for 2 hours, and then cooled to room temperature; after reduction, a sample—Pt 1+C Co/CaCoTiO 3 (wherein Pt was on the Co particles with The single-atom and cluster forms coexist, corresponding to Pt 1+C Co/rCCT).
  • Comparative Example 1 Comparative sample—PtCo/CaCoTiO 3 catalyst (Pt 1 Co/rCCT, that is, Pt exists only in the form of single atoms)
  • the first sample is that Pt and Co exist in the catalyst in the form of a single-atom alloy, and the preparation method of the catalyst includes the following steps:
  • solution B In another container, take an equal volume of tetrabutyl titanate and mix with absolute ethanol to obtain solution B, which is clear and transparent;
  • the solution B was added dropwise to the solution A, and after the dropwise addition was completed, the pH value of the mixed solution was adjusted to 6, and the wet gel was formed by continuing to keep stirring for 5 hours at 40°C;
  • the wet gel was dried in an oven at 80°C for 48 hours to form a dry gel.
  • the temperature was raised from room temperature to 300°C at a heating rate of 2°C/min in a muffle furnace and then heated to 300°C. Hold for 2h, then drop to room temperature, and then increase the temperature from room temperature to 600°C at a heating rate of 5°C/min and hold for 2h to obtain the CaCoTiO 3 composite oxide carrier;
  • the reduction of the carrier is to spread the solid powder of the CaCoTiO composite oxide carrier on the bottom of the porcelain boat, and then put the porcelain boat into the constant temperature zone in the center of the quartz tube of the tube furnace, and evacuated with a vacuum pump in a closed state. Then slowly introduce reducing gas until the pressure value reaches normal pressure, keep the gas flow rate at 40ml/min, and gradually heat up the tube furnace at a heating rate of 10°C/min. When the temperature of the constant temperature zone in the center of the quartz tube reaches 600°C , kept for 2h, and then cooled to room temperature to obtain Co/CaCoTiO 3 ;
  • the solid product is repeatedly washed three times with deionized water, centrifuged after each washing, and the solid product is washed once with absolute ethanol after the washing is completed. , and then the washed solid product was vacuum-dried at 60 ° C for 24 h to obtain a PtCo/CaCoTiO 3 catalyst, the above-mentioned solid powder was spread on the bottom of the porcelain boat, and then the porcelain boat was put into the quartz vessel of the tube furnace.
  • the second comparative sample is that Pt exists in the catalyst in the form of clusters on Co particles, and the preparation method of the catalyst includes the following steps:
  • solution B In another container, take an equal volume of 6.807g of tetrabutyl titanate and mix with 6.8ml of absolute ethanol to obtain solution B, which is clear and transparent;
  • the solution B was added dropwise to the solution A, and after the dropwise addition was completed, the pH value of the mixed solution was adjusted to 6, and the wet gel was formed by continuing to keep stirring for 5 hours at 40°C;
  • the wet gel was dried in an oven at 80°C for 48 hours to form a dry gel.
  • the temperature was raised from room temperature to 300°C at a heating rate of 2°C/min in a muffle furnace and then heated to 300°C. Hold for 2h, then drop to room temperature, and then increase the temperature from room temperature to 600°C at a heating rate of 5°C/min and hold for 2h to obtain the CaCoTiO 3 composite oxide carrier;
  • the reduction of the carrier is to spread the solid powder of the CaCoTiO composite oxide carrier on the bottom of the porcelain boat, and then put the porcelain boat into the constant temperature zone in the center of the quartz tube of the tube furnace, and evacuated with a vacuum pump in a closed state. Then slowly introduce hydrogen until the pressure value reaches normal pressure, keep the gas flow rate at 40ml/min, and gradually heat up the tube furnace at a heating rate of 10°C/min. When the temperature of the constant temperature zone in the center of the quartz tube reaches 600°C, keep 2h, and then cooled to room temperature to obtain Co/CaCoTiO 3 ;
  • the solid product is repeatedly washed three times with deionized water, centrifuged after each washing, and the solid product is washed once with absolute ethanol after the washing is completed. , and then the washed solid product was vacuum-dried at 60°C for 24 hours to obtain a PtC Co /CaCoTiO 3 catalyst, the above-mentioned solid powder was spread on the bottom of the porcelain boat, and then the porcelain boat was placed in a tube furnace The central constant temperature zone of the quartz tube is evacuated with a vacuum pump in a closed state, and then the reducing gas is slowly introduced until the pressure value reaches normal pressure, and the gas flow rate is kept at 40ml/min, and the tube is gradually heated at a heating rate of 10°C/min.
  • the furnace was heated, and when the temperature in the constant temperature zone in the center of the quartz tube reached 600 °C, it was kept for 2 h, and then cooled to room temperature to obtain a three-PtC Co/CaCoTiO 3 catalyst of the comparative sample, which was denoted as Pt C Co /rCCT.
  • Example 1 is a schematic diagram of the catalyst preparation process of Example 1 (b in FIG. 1 ), Comparative Example 1 (a in FIG. 1 ) and Comparative Example 2 (c in FIG. 1 ).
  • the potential displacement method was used to precisely control the dispersion state of Pt on the Co/rCCT surface.
  • Pt exists in the form of coexistence of single atoms and groups
  • Pt exists only in the form of single atoms
  • Pt exists only in the form of groups.
  • Figure 2 shows the surface structure of PtCo particles and the distribution of Pt on Co nanoparticles of the three samples of Example 1, Comparative Example 1 and Comparative Example 2 using HAADF-STEM electron microscope technology. It can be seen from the figure that the dark field high resolution The surface atomic results of PtCo nanoparticles can be observed in the HAADF-STEM images.
  • Pt in the catalyst of Comparative Sample 1 is distributed on the Co particles as isolated single atoms (red circles); as can be seen from Figure 2b, Pt in the catalyst of Example 1 is distributed on Co particles. There are isolated single atoms (red circles) and Pt cluster structures (yellow circles), and single-atom Pt surrounds the Pt clusters.
  • FIG 3 is a supplementary image of the electron microscope of PtCo nanoparticles, supporting the above results. It can be seen from the EDX mapping that PtCo nanoparticles are mainly composed of Pt (yellow) and Co (pink) elements, Pt 1 Co/rCCT (representing Comparative Example 1), Pt 1+C Co/rCCT (representing Example 1) and The aggregation state of Pt (yellow) in Pt C Co/rCCT (representing Comparative Example 2) gradually increased. In addition, a partial distribution of Ti (green) and O (red) was observed on the surface of PtCo nanoparticles, which was preliminarily speculated to be amorphous TiO x species.
  • the catalyst of Example 1 shows excellent performance whether it is from the slurry bed reaction or the kettle reaction data.
  • the present invention studies the adsorption activation mode of primary hydroxyl groups by in-situ infrared adsorption and desorption of propanol.
  • FIG. 4 The infrared absorption spectra of propanol in Comparative Example 1, Example 1 and Comparative Example 2 are shown in FIG. 4 . It can be seen from A in Figure 4 that the main vibration peaks of propanol on Comparative Sample 1 are 2969, 2941, 2885, 1471, 1447, 1407, 1340, 1231, 1185, 1067, 1053 cm -1 .
  • 2969, 2941, and 2885 cm -1 belong to the stretching vibrations of CH3 and CH2 in the adsorbed alkoxy group
  • 1471, 1447, 1407 cm -1 are the CH2 and CH3 deformation vibrations of undissociated adsorbed propanol, respectively
  • 1231 cm -1 is the deformation vibration of undissociated OH
  • 1185 cm-1 is the deformation vibration of CC
  • 1067 and 1053 cm -1 are the undissociated and dissociated CO stretching vibrations, respectively [59-62].
  • the absorption peak at 1470 cm -1 of the catalyst sample of Example 1 is obviously enhanced, but the absorption peak at 1340 cm -1 does not appear.
  • Pt 1 -CoOx structure has the ability to adsorb and activate CH; but From the adsorption strength of OH and CO, the adsorption capacity of Pt C to hydroxyl group is stronger, indicating that Pt clusters have advantages in the adsorption of hydroxyl group. From the C in Figure 4 of the adsorption infrared spectrum of the Pt 1+C Co/rCCT sample to propanol, it can be seen that Pt 1 and Pt n have synergistic adsorption and activation functions in these two aspects.
  • the Co-doped perovskite structure precursor is first synthesized. It can be seen from the figure that the characteristic diffraction peaks of perovskite structure appear at 23.39°, 33.32°, 39.29°, 41.11°, 47.83°, 59.54°, and 69.97°, which are respectively attributed to (200), ( 022), (-113), (-222), (400), (-224), (440) crystal planes, indicating that the carrier CaCoTiO 3 belongs to the monoclinic crystal structure (JCPDS 34-0394).
  • Pt 1 Co/rCCT represents Comparative Example 1
  • Pt 1+C Co/rCCT represents Example 1
  • Pt C Co/rCCT represents Comparative Example 2.

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Abstract

本发明涉及一种高效催化甘油氧化制备甘油酸的催化剂、其制备方法及用途，所述催化剂为Pt 1+CCo/CaCoTiO 3，其中，载体CaCoTiO 3的XRD表征图在2θ为23.39°、33.32°、39.29°、41.11°、59.54°和69.97°处出现钙钛矿结构特征衍射峰，分别归属于CaCoTiO 3中的(200)、(022)、(-113)、(-222)、(400)、(-224)、(440)晶面；作为载体的CaCoTiO 3为单斜晶体结构JCPDS34-0394；并且Pt和Co以纳米粒子形式存在，平均粒径为2nm±0.2nm。本发明的催化剂由于Pt单原子(用Pt 1表示)和Pt团簇(用Pt C表示)共存进而形成了协同催化的作用，在进行甘油氧化制备甘油酸的反应中，Pt单原子位点活化甘油的C-H键以及醛基的C-H键，Pt团簇位点活化甘油的O-H键，以及实现了OH*(羟基新物质)的插入以及酸(反应体系中存在的酸物质)的脱除。

Description

一种高效催化甘油氧化制备甘油酸的催化剂、其制备方法及用途 技术领域
本发明涉及化学化工及催化剂领域，尤其涉及一种高效催化甘油氧化制备甘油酸的催化剂及其制备方法。
背景技术
生物质能源是一种理想的可再生替代资源，鉴于生物质能源污染小、可再生性等优异性能，生物质能源的开发、利用受到广泛的关注。甘油是生物柴油酯交换过程中产生的副产物(每生产一吨生物柴油产生100Kg甘油)，然而其下游转化能力不足，出现产能过剩。因此，催化甘油转化成高附加值的产物具有重要意义。
甘油酸是一种多功能的高价值精细化学品，可运用于在医药、食品行业，同时也是一种重要的中间体。现有的甘油氧化制备甘油酸的催化剂主要分为均相催化法、多相催化法。目前，由于多相催化在反应控制上易操作，工艺流程简单，绿色，因此多相催化一直备受研究者的青睐。近些年，甘油的多相催化氧化制备目标成为研究热点。研究报道中还存有很多的问题，如催化活性不高，选择性差，反应条件限制(外加碱)，催化剂失活等。
现有技术中，由甘油制备甘油酸需要经过两个反应步骤，首先第一步甘油氧化脱氢生成醛，然后第二步是甘油醛中插入OH*物种生成甘油酸。醇的氧化脱氢过程主要是以氧气作为氧化剂，甘油伯羟基、α-位C-H的氢断裂与氧气活化产生的一个氧原子结合生成水脱去，醛的氧化涉及醛基与α-位C-H的氢的活化，在水溶液氧气活化生成OH*物种插入。甘油高效制备甘油酸需要选择性活化伯羟基、抑制深度氧化以及避免C-C键断裂。关于OH*(羟基活性物质)参见Science 2010 VOL330，P74的文献。
Pt基双金属催化剂用于液相条件下催化甘油选择性氧化制备甘油酸，研究者将非贵金属Co、Cu、Sn添加到Pt基催化剂中得到了更优异的性能。微波辐射制备了高分散的PtCo双金属纳米粒子，与Pt/RGO和Co/RGO相比，PtCo/RGO对甘油的氧化性能有显著提高，甘油转化率(70.2％)和甘油酸的选择性(85.9％)均明显高于单金属Pt/RGO和Co/RGO(J.Catalysis Today,2017,298:234–240)。在相同的反应条件下，2.0％Pt/C-R催化的甘油转化率较低，2h的转化率仅为29.8％，加入Sn后，2.0％Pt 9Sn 1/C-R增加到了43.1％，反应6h后，甘油转化率达到了91.1％，主要原因是加入的Sn能够促进氧分子的活化(J.Applied Catalysis B Environmental,2016,180:78–85)。高分散的Pt-Cu/C催化剂，发现Pt-Cu/C比Pt/C对选择性氧化甘油为甘油酸的活性更强，无碱条件下反应6h，甘油转化率为86.2％时，甘油酸的选择性达到了70.8％(J.Catalysis Communications,2011,12(12): 1059-1062)。
然而，前述现有的研究报道中仍然存在着一些问题，如反应条件需要有碱的参与，造成环境的污染，并且催化剂的选择性和活性仍然不够理想，因此，有针对性的提供一种能够实现在无碱条件下进行甘油氧化制备甘油酸的高活性、高选择性催化剂，是亟待解决的技术问题。
发明内容
为解决前述缺陷，本发明提供一种高效催化甘油氧化制备甘油酸的催化剂，所述催化剂具有Pt单原子和Pt簇的协同作用，具有更优异的催化性能。
本发明提供一种高效催化甘油氧化制备甘油酸的催化剂，所述催化剂为PtCo/CaCoTiO 3，载体CaCoTiO 3的XRD表征图在2θ为23.39°、33.32°、39.29°、41.11°、59.54°和69.97°处出现钙钛矿结构特征衍射峰，分别归属于CaCoTiO 3中的(200)、(022)、(-113)、(-222)、(400)、(-224)、(440)晶面；作为载体的CaCoTiO 3为单斜晶体结构JCPDS34-0394；并且Pt和Co以纳米粒子形式存在，平均粒径为2nm±0.2nm。
本发明进一步还提供前述催化剂的制备方法，包括以下步骤：
1)载体的制备
采用溶胶凝胶法合成CaCoTiO 3复合氧化物载体；
2)对载体进行还原
取所述CaCoTiO 3复合氧化物载体在氢气气氛下进行还原，得到Co/CaCoTiO 3；
3)Pt的置换
将所述Co/CaCoTiO 3用去离子水液封倒入容器中，然后在磁力搅拌和惰性气体的氛围中，向所述容器中滴加H 2PtCl 6水溶液，在常温和剧烈搅拌下反应，待反应结束后对固体产物进行反复洗涤后，将所述固体产物在真空条件下干燥，得到PtCo/CaCoTiO 3催化剂。
进一步地，步骤1)中，取Ca(NO 3) 2·4H 2O和Co(NO 3) 2·6H 2O配制成混合溶液，搅拌混合均匀后，再加入C 6H 8O 7·H 2O(一水合柠檬酸)继续搅拌，得溶液A；
在另一个容器中取钛酸四丁酯与无水乙醇混合均匀得溶液B；
然后将所述溶液B逐滴滴加到所述溶液A中，待滴加完成后，再调节混合溶液的pH值到5-7，继续保温搅拌制备形成湿凝胶；
将所述湿凝胶进行烘干，得到干凝胶，将所述干凝胶研磨后焙烧处理用于去除柠檬酸，待降至室温后再进行二次焙烧，得CaCoTiO 3复合氧化物。
进一步地，所述Ca(NO 3) 2·4H 2O和所述Co(NO 3) 2·6H 2O摩尔配比为1：(0.1-0.3)；优选地，所述摩尔配比为1：0.2。
进一步地，所述C 6H 8O 7·H 2O(一水合柠檬酸)的加入量为金属离子摩尔数的1-5倍，所述金属离子为Ca离子、Co离子和Ti离子；优选地，所述加入量为金属离子摩尔数的1-2倍。
进一步地，步骤1)中，加入C 6H 8O 7·H 2O后，继续搅拌0.1-1h。
进一步地，步骤1)中，所述钛酸四丁酯与所述无水乙醇的体积比为1：(1-3)。
进一步地，步骤1)中，所述钛酸四丁酯与所述无水乙醇混合均匀，继续搅拌时间为0.1-2h，搅拌得到澄清透明的溶液B。
进一步地，步骤1)中，用氨水调节pH值到6。
进一步地，步骤1)中，调节pH值后，在30-50℃恒温搅拌3-6h。
进一步地，步骤1)中，所述湿凝胶在60-90℃条件下干燥24-72h形成干凝胶。
进一步地，步骤1)中，所述干凝胶研磨成粉末，然后在马弗炉中由室温升温到260-350℃并保持1-5h，其中，升温速率为2℃/min。升温速率为2℃/min，用以除去柠檬酸。优选地，升温到300℃。
进一步地，步骤1)中，所述二次焙烧为，将降至室温的经焙烧后的固体再将由室温升至550-650℃并保持1.5-3h，升温速率为5℃/min。
进一步地，步骤2)中，对载体进行还原是将所述CaCoTiO 3复合氧化物的固体粉末平铺在瓷舟底部，然后将所述瓷舟放入管式炉的石英管中心恒温区，在密闭状态下用真空泵抽空空后再缓慢通入还原性气体至压力值达到常压，保持气体流速为40ml/min，以10℃/min的升温速率逐渐使管式炉升温，当石英管中心恒温区的温度达到550-650℃时，保持1.5-3h，然后再冷却至室温，得到Co/CaCoTiO 3复合氧化物。优选地，所述恒温区的温度达到600℃、保持时间为2h。
进一步地，步骤3)中，将所述Co/CaCoTiO 3复合氧化物用去离子水液封倒入容器中，在600-800转/min的搅拌和氮气保护下，向容器中滴加H 2PtCl 6水溶液，在常温下剧烈搅拌15-72h，发生的置换反应离子方程式如下：
2Co(s)+PtCl 6 2-(aq)＝Pt(s)+2Co 2+(aq)+6Cl -(aq)
置换反应结束后，将固体产物分离后，用去离子水对所述固体产物反复洗涤，每次洗涤后都用进行离心分离，完成洗涤后再用无水乙醇对所述固体产物进行冲洗至少一次，然后将洗涤处理后的所述固体产物在50-70℃下真空干燥0.1-48h，得到PtCo/CaCoTiO 3催化剂。优选地，真空干燥的温度为60℃、时间为24h。优选地，所述剧烈搅拌为700转/min。
本发明进一步还提供前述催化剂的用途，尤其是用于甘油氧化制备甘油酸反应中的用途。使用本发明催化剂，能够使甘油的转化率达到99.0％，甘油的选择性达到72.0％，甘油酸产物的拈花一笑达到71.1％。
本发明的有益效果在于：
1、本发明的催化剂，通过制备过程中原料以及制备条件的配合，能够实现精准控制Pt单原子和Pt团簇共存的催化剂结构；
2、在本发明的催化剂中，由于Pt单原子(用Pt 1表示)和Pt团簇(用Pt C表示)共存进而形成了协同催化的作用，在进行甘油氧化制备甘油酸的反应中，Pt单原子位点活化甘油的C-H键以及醛基的C-H键，Pt团簇位点活化甘油的O-H键，以及实现了OH*(羟基新物质)的插入以及酸(反应体系中存在的酸物质)的脱除；
3、通过使用本发明的催化剂，能够实现在进行甘油氧化制备甘油酸的反应中，甘油的转化率为99.0％，甘油酸的选择性达到72.0％，甘油酸产物的收率达到71.1％。
附图说明
图1为实施例1和对比例1、对比例2制备催化剂的过程示意图；
图2为实施例1和对比例1、对比例2制备的催化剂的HADDF-STEM电镜图；
图3为实施例1和对比例1、对比例2制备的催化剂的电镜补充图；
图4为实施例1和对比例1、对比例2制备的催化剂的丙醇吸/脱附测试曲线
图5为实施例1和对比例1、对比例2制备的催化剂的丙醇吸附构型模拟图；
图6为载体复合氧化物、以及制备各步骤对应产物的XRD表征图。
具体实施方式
实施例1 样品一Pt 1+CCo/CaCoTiO 3催化剂(Pt 1+CCo/rCCT，其中Co/rCCT为钙钛矿中还原得到的Co颗粒)
所述样品二是Pt在Co颗粒以单原子和团簇形式存在在催化剂中，所述催化剂的制备方法，包括以下步骤：
1)载体的制备
在一个容器中取5.244g Ca(NO 3) 2·4H 2O和0.6467g Co(NO 3) 2·6H 2O溶解于30ml去离子水中配制成混合溶液，搅拌混合均匀后，再加入金属离子总和摩尔数1.25倍的C 6H 8O 7·H 2O(即11.667g一水合柠檬酸)继续搅拌，得溶液A；
在另一个容器中取等体积的6.807g钛酸四丁酯与6.8mL无水乙醇混合均匀得溶液B，所述溶液B为澄清透明的性状；
然后将所述溶液B逐滴滴加到所述溶液A中，待滴加完成后，再调节混合溶液的pH值到6，在40℃条件下继续保温搅拌5h制备形成湿凝胶；
然后将所述湿凝胶放置在80℃烘箱中烘干48h形成干凝胶，将所述干凝胶研磨后，在马弗炉中由室温以2℃/min的升温速率升温至300℃并保持2h，后降至室温，再由室温以5℃/min的升温速率升温至600℃并保持2h，得到CaCoTiO 3复合氧化物载体；
所述载体CaCoTiO 3的XRD表征图在2θ为23.39°、33.32°、39.29°、41.11°、59.54°和69.97°处出现钙钛矿结构特征衍射峰，分别归属于CaCoTiO 3中的(200)、(022)、(-113)、(-222)、(400)、(-224)、(440)晶面；作为载体的CaCoTiO 3为单斜晶体结构JCPDS34-0394；
2)对载体进行还原
对载体进行还原是将所述CaCoTiO 3复合氧化物载体的固体粉末平铺在瓷舟底部，然后将所述瓷舟放入管式炉的石英管中心恒温区，在密闭状态下用真空泵抽空空后再缓慢通入氢气至压力值达到常压，保持气体流速为40ml/min，以10℃/min的升温速率逐渐使管式炉升温，当石英管中心恒温区的温度达到600℃时，保持2h，然后再冷却至室温，得到Co/CaCoTiO 3；
3)Pt的置换
取0.3g所述Co/CaCoTiO 3用5ml除去氧的去离子水直接液封然后倒入容器中，然后在700转/min的磁力搅拌和氮气的氛围中，向所述容器中滴加15.4mol/L的H 2PtCl 6水溶液10ml，在常温和剧烈搅拌下反应12h，发生的置换反应离子方程式如下：
2Co(s)+PtCl 6 2-(aq)＝Pt(s)+2Co 2+(aq)+6Cl -(aq)
置换反应结束后，将固体产物分离后，用去离子水对所述固体产物反复洗涤三次，每次洗涤后都用进行离心分离，完成洗涤后再用无水乙醇对所述固体产物进行冲洗一次，然后将洗涤处理后的所述固体产物在60℃下真空干燥24h，得到PtCo/CaCoTiO 3催化剂；将所述PtCo/CaCoTiO 3催化剂的固体粉末平铺在瓷舟底部，然后将所述瓷舟放入管式炉的石英管中心恒温区，在密闭状态下用真空泵抽空空后再缓慢通入氢气至压力值达到常压，保持气体流速为40ml/min，以10℃/min的升温速率逐渐使管式炉升温，当石英管中心恒温区的温度达到600℃时，保持2h，然后再冷却至室温；还原后得样品一Pt 1+CCo/CaCoTiO 3(其中，Pt在Co颗粒上以单原子和团簇形式共同存在，对应Pt 1+CCo/rCCT)。
对比例1 对比样品一PtCo/CaCoTiO 3催化剂(Pt 1Co/rCCT即Pt仅以单原子形式存在)
所述样品一是Pt和Co以单原子合金形式存在在催化剂中，所述催化剂的制备方法，包括以下步骤：
1)载体的制备
在一个容器中取5.244g Ca(NO 3) 2·4H 2O和0.6467g Co(NO 3) 2·6H 2O溶解于30ml去离子水中配制成混合溶液，搅拌混合均匀后，再加入金属离子总和摩尔数1.25倍的C 6H 8O 7·H 2O(即11.667g一水合柠檬酸)继续搅拌，得溶液A；
在另一个容器中取等体积的钛酸四丁酯与无水乙醇混合均匀得溶液B，所述溶液B为澄清透明的性状；
然后将所述溶液B逐滴滴加到所述溶液A中，待滴加完成后，再调节混合溶液的pH值到6，在40℃条件下继续保温搅拌5h制备形成湿凝胶；
然后将所述湿凝胶放置在80℃烘箱中烘干48h形成干凝胶，将所述干凝胶研磨后，在马弗炉中由室温以2℃/min的升温速率升温至300℃并保持2h，后降至室温，再由室温以5℃/min的升温速率升温至600℃并保持2h，得到CaCoTiO 3复合氧化物载体；
2)对载体进行还原
对载体进行还原是将所述CaCoTiO 3复合氧化物载体的固体粉末平铺在瓷舟底部，然后将所述瓷舟放入管式炉的石英管中心恒温区，在密闭状态下用真空泵抽空空后再缓慢通入还原性气体至压力值达到常压，保持气体流速为40ml/min，以10℃/min的升温速率逐渐使管式炉升温，当石英管中心恒温区的温度达到600℃时，保持2h，然后再冷却至室温，得到Co/CaCoTiO 3；
3)Pt的置换
将所述0.3g Co/CaCoTiO 3用5ml除去氧的去离子水直接液封然后倒入容器中，然后在700转/min的磁力搅拌和氮气的氛围中，向所述容器中滴加1.5mol/LH 2PtCl 6水溶液10ml，在常温和剧烈搅拌下反应10min，发生的置换反应离子方程式如下：
2Co(s)+PtCl 6 2-(aq)＝Pt(s)+2Co 2+(aq)+6Cl -(aq)
置换反应结束后，将固体产物分离后，用去离子水对所述固体产物反复洗涤三次，每次洗涤后都用进行离心分离，完成洗涤后再用无水乙醇对所述固体产物进行冲洗一次，然后将洗涤处理后的所述固体产物在60℃下真空干燥24h，得到PtCo/CaCoTiO 3催化剂，将上述固体粉末平铺在瓷舟底部，然后将所述瓷舟放入管式炉的石英管中心恒温区，在密闭状态下用真空泵抽空空后再缓慢通入还原性气体至压力值达到常压，保持气体流速为40ml/min，以10℃/min的升温速率逐渐使管式炉升温，当石英管中心恒温区的温度达到600℃时，保持2h，然后再冷却至室温，得到Pt 1Co/CaCoTiO 3，其中，Pt在Co上以单原子形式存在，对应Pt 1Co/rCCT。
对比例2 对比样品二PtcCo/CaCoTiO 3催化剂(Pt CCo/rCCT即Pt仅以团簇形式存在)
所述对比样品二是Pt在Co颗粒上以团簇形式存在在催化剂中，所述催化剂的制备方法，包括以下步骤：
1)载体的制备
在一个容器中取5.244g Ca(NO 3) 2·4H 2O和0.6467g Co(NO 3) 2·6H 2O溶解于30ml去离子水中配制成混合溶液，搅拌混合均匀后，再加入金属离子总和摩尔数1.25倍的C 6H 8O 7·H 2O(即11.667g一水合柠檬酸)继续搅拌，得溶液A；
在另一个容器中取等体积的6.807g钛酸四丁酯与6.8ml无水乙醇混合均匀得溶液B，所述溶液B为澄清透明的性状；
然后将所述溶液B逐滴滴加到所述溶液A中，待滴加完成后，再调节混合溶液的pH值到6，在40℃条件下继续保温搅拌5h制备形成湿凝胶；
然后将所述湿凝胶放置在80℃烘箱中烘干48h形成干凝胶，将所述干凝胶研磨后，在马弗炉中由室温以2℃/min的升温速率升温至300℃并保持2h，后降至室温，再由室温以5℃/min的升温速率升温至600℃并保持2h，得到CaCoTiO 3复合氧化物载体；
2)对载体进行还原
对载体进行还原是将所述CaCoTiO 3复合氧化物载体的固体粉末平铺在瓷舟底部，然后将所述瓷舟放入管式炉的石英管中心恒温区，在密闭状态下用真空泵抽空空后再缓慢通入氢气至压力值达到常压，保持气体流速为40ml/min，以10℃/min的升温速率逐渐使管式炉升温，当石英管中心恒温区的温度达到600℃时，保持2h，然后再冷却至室温，得到Co/CaCoTiO 3；
3)Pt的置换
将0.3g所述Co/CaCoTiO 3用5ml除去氧的去离子水直接液封然后倒入容器中，然后在700转/min的磁力搅拌和氮气的氛围中，向所述容器中滴加1.5mol/LH 2PtCl 6水溶液10ml，在常温和剧烈搅拌(700转/min)下反应24h，发生的置换反应离子方程式如下：
2Co(s)+PtCl 6 2-(aq)＝Pt(s)+2Co 2+(aq)+6Cl -(aq)
置换反应结束后，将固体产物分离后，用去离子水对所述固体产物反复洗涤三次，每次洗涤后都用进行离心分离，完成洗涤后再用无水乙醇对所述固体产物进行冲洗一次，然后将洗涤处理后的所述固体产物在60℃下真空干燥24h，得到Pt CCo/CaCoTiO 3催化剂，将上述固体粉末平铺在瓷舟底部，然后将所述瓷舟放入管式炉的石英管中心恒温区，在密闭状态下用真空泵抽空空后再缓慢通入还原性气体至压力值达到常压，保持气体流速为40ml/min，以10℃/min的升温速率逐渐使管式炉升温，当石英管中心恒温区的温度达到600℃时，保持2h，然后再冷却至室温，得到对比样品三Pt CCo/CaCoTiO 3催化剂，记为Pt CCo/rCCT。
图1为实施例1(图1中的b)、对比例1(图1中的a)和对比例2(图1中的c)的催化剂制备过程的示意图，从图中可见，本发明通过采用电位置换法精准控制Pt在Co/rCCT表面的分散状态。在实施例1的催化剂中，Pt以单原子和团族共存的形式存在；对比例1的催化剂中，Pt仅以单原子形式存在；对比例2的催化剂中，Pt仅以团族形式存在。
图2为采用HAADF-STEM电镜技术观察实施例1、对比例1和对比例2三个样品的PtCo颗粒的表面结构以及Pt在Co纳米颗粒上的分布情况，从图中可见，暗场高分辨HAADF-STEM照片可以观察到PtCo纳米颗粒的表面原子结果。从图2的a中可见，对比样品一的催化剂中Pt在Co颗粒上呈孤立单原子(红色圈)分布；从图2的b中可见，实施例1样品的催化剂中Pt在Co颗粒上既存在孤立单原子(红色圈)也存在Pt团簇结构(黄色圈)，单原子Pt环绕在Pt团簇周围，通过统计Pt原子个数比发现Pt 1/Pt C＝1/3；从图2的c中可见，对比样品二的催化剂中Pt在Co颗粒上以团簇形式存在。颜色分辨的暗场高分辨HAADF-STEM照片可以进一步印证上述结构。
图3为PtCo纳米颗粒电镜补充图，辅助证明以上结果。从EDX mapping中可以看出PtCo纳米颗粒主要由Pt(黄色)和Co(粉色)元素组成，Pt 1Co/rCCT(代表对比例1)、Pt 1+CCo/rCCT(代表实施例1)及Pt CCo/rCCT(代表对比例2)中Pt(黄色)的聚集状态逐渐增加。此外，观察到PtCo纳米颗粒表面有部分Ti(绿色)与O(红色)的分布，初步推测其为无定型的TiO x物种。进一步通过明场高分辨HAADF-STEM照片，发现PtCo颗粒表面存在一层包覆层，通过在颗粒外(I)、颗粒表面(II)及载体(III)上EELS选点测定，发现在颗粒表面上出现明显的Ti和O的激发态信号。推断置换Pt后经600℃处理，形成了纳米颗粒与载体的强界面相互作用，在纳米颗粒表面出现TiO x物种。
从图4的催化剂的丙醇吸/脱附性能测试结果可见，不管是从浆态床反应还是釜式反应数据都可以看出实施例1的催化剂都表现了优异的性能。进一步为了探究甘油在PtCo催化剂表面的吸附模式，本发明通过采用丙醇的原位红外吸脱附来进行对伯羟基的吸附活化模式的研究。
丙醇在对比例1、实施例1和对比例2上的红外吸收谱图如图4所示。由图4中的A可知，丙醇在对比样品1上的主要振动峰有2969、2941、2885、1471、1447、1407、1340、1231、1185、1067、1053cm -1。其中2969、2941、2885cm -1归属于吸附烷氧基中CH 3和CH 2伸缩振动，1471和1447、1407cm -1分别为未解离吸附丙醇的CH 2和CH 3变形振动，1231cm -1为未解离的O-H的变形振动，1185cm-1为C-C的变形振动，1067和1053cm -1分别为未解离和解离的C-O伸缩振动[59-62]。由图4中的C可和，实施例1的催化剂样品在1470cm -1的吸收峰明显的增强，而未出现1340cm -1的吸收峰，推测Pt 1-CoOx结构有吸附活化C-H的能力；但从O-H和C-O的吸附强度看Pt C对羟基的吸附能力更强，说明Pt团簇对羟基的吸附是存在优势的。从Pt 1+CCo/rCCT样品对丙醇 的吸附红外谱图的图4中的C可以看出Pt 1和Pt n是存在这两方面吸附活化功能的协同的。Pt 1+CCo/rCCT样品上C-O键及CH 3和CH 2吸收强度明显强于对比例1和对比例2的催化剂样品，且存在多个羟基变形振动峰说明Pt 1+CCo/rCCT对羟基的吸附是最强的，其中也观察到1340cm -1的CH变形振动，说明Pt1和Ptn对丙醇的吸附活化是存在协同的。
基于对原位红外丙醇吸附谱图的分析，对丙醇在对比例1(图5中的A)、实施例1(图5中的B)和对比例2(图5中的C)的吸附构型进行了模拟，见图5，由于Pt 1-CoO x有吸附活化C-H键的能力，Pt团簇对伯羟基的吸附能力更强。其中棕球为Co、黄球为Pt、白球为H、灰球为C、红球为O。
从图6可见，催化制备制备过程中，首先合成Co掺杂的钙钛矿结构前体。图中可已看出，在23.39°、33.32°、39.29°、41.11°、47.83°、59.54°、69.97°处出现钙钛矿结构特征衍射峰，分别归属于CaTiO 3中的(200)、(022)、(-113)、(-222)、(400)、(-224)、(440)晶面，说明载体CaCoTiO 3属于单斜晶体结构(JCPDS 34-0394)。图中，Pt 1Co/rCCT代表对比例1、Pt 1+CCo/rCCT代表实施例1、Pt CCo/rCCT代表对比例2。
以上所述，仅是本发明的较佳实施例而已，并非是对本发明作任何其他形式的限制，而依据本发明的技术实质所作的任何修改或等同变化，仍属于本发明所要求保护的范围。

Claims (10)

  1. 一种高效催化甘油氧化制备甘油酸的催化剂，其特征在于，所述催化剂为Pt 1+CCo/CaCoTiO 3，其中，载体CaCoTiO 3的XRD表征图在2θ为23.39°、33.32°、39.29°、41.11°、59.54°和69.97°处出现钙钛矿结构特征衍射峰，分别归属于CaCoTiO 3中的(200)、(022)、(-113)、(-222)、(400)、(-224)、(440)晶面；作为载体的CaCoTiO 3为单斜晶体结构JCPDS34-0394；并且Pt和Co以纳米粒子形式存在，平均粒径为2nm±0.2nm。
  2. 一种权利要求1所述催化剂的制备方法，其特征在于，包括以下步骤：
    1)载体的制备
    采用溶胶凝胶法合成CaCoTiO 3复合氧化物载体；
    2)对载体进行还原
    取所述CaCoTiO 3复合氧化物载体在氢气气氛下进行还原，得到Co/CaCoTiO 3；
    3)Pt的置换
    将所述Co/CaCoTiO 3用去离子水液封倒入容器中，然后在磁力搅拌和惰性气体的氛围中，向所述容器中滴加H 2PtCl 6水溶液，在常温和剧烈搅拌下反应，待反应结束后对固体产物进行反复洗涤后，将所述固体产物在真空条件下干燥，得到PtCo/CaCoTiO 3催化剂；对所述PtCo/CaCoTiO 3催化剂进行二次还原，最终得到催化剂Pt 1+CCo/CaCoTiO 3。
  3. 根据权利要求2所述的制备方法，其特征在于，步骤1)中，取Ca(NO 3) 2·4H 2O和Co(NO 3) 2·6H 2O配制成混合溶液，搅拌混合均匀后，再加入C 6H 8O 7·H 2O(一水合柠檬酸)继续搅拌，得溶液A；
    在另一个容器中取钛酸四丁酯与无水乙醇混合均匀得溶液B；
    然后将所述溶液B逐滴滴加到所述溶液A中，待滴加完成后，再调节混合溶液的pH值到5-7，继续保温搅拌制备形成湿凝胶；
    将所述湿凝胶进行烘干，得到干凝胶，将所述干凝胶研磨后焙烧处理用于去除柠檬酸，待降至室温后再进行二次焙烧，得CaCoTiO 3复合氧化物。
  4. 根据权利要求2所述的制备方法，其特征在于，所述Ca(NO 3) 2·4H 2O和所述Co(NO 3) 2·6H 2O摩尔配比为1：(0.1-0.3)；优选地，所述摩尔配比为1：0.2。
  5. 根据权利要求2所述的制备方法，其特征在于，所述C 6H 8O 7·H 2O(一水合柠檬酸)的加入量为金属离子摩尔数的1-5倍。
  6. 根据权利要求2所述的制备方法，其特征在于，步骤1)中，加入C 6H 8O 7·H 2O后，继续搅拌0.1-1h。
  7. 根据权利要求2所述的制备方法，其特征在于，步骤1)中，所述钛酸四丁酯与所述无水乙醇的体积比为1：(1-3)。
  8. 根据权利要求2所述的制备方法，其特征在于，步骤2)中，对载体进行还原是将所述CaCoTiO 3复合氧化物的固体粉末平铺在瓷舟底部，然后将所述瓷舟放入管式炉的石英管中心恒温区，在密闭状态下用真空泵抽空空后再缓慢通入还原性气体至压力值达到常压，保持气体流速为40ml/min，以10℃/min的升温速率逐渐使管式炉升温，当石英管中心恒温区的温度达到550-650℃时，保持1.5-3h，然后再冷却至室温，得到Co/CaCoTiO 3复合氧化物。优选地，所述恒温区的温度达到600℃、保持时间为2h。
  9. 根据权利要求2所述的制备方法，其特征在于，步骤3)中，将所述Co/CaCoTiO 3复合氧化物用去离子水液封倒入容器中，在600-800转/min的搅拌和氮气保护下，向容器中滴加H 2PtCl 6水溶液，在常温下剧烈搅拌15-72h，发生的置换反应离子方程式如下：
    2Co(s)+PtCl 6 2-(aq)＝Pt(s)+2Co 2+(aq)+6Cl -(aq)
    置换反应结束后，将固体产物分离后，用去离子水对所述固体产物反复洗涤，每次洗涤后都用进行离心分离，完成洗涤后再用无水乙醇对所述固体产物进行冲洗至少一次，然后将洗涤处理后的所述固体产物在50-70℃下真空干燥0.1-48h，得到PtCo/CaCoTiO 3催化剂；优选地，真空干燥的温度为60℃、时间为24h。
  10. 一种权利要求2-9任一项所述方法制备得到的催化剂用于催化反应的用途；优选地，所述用途为用于甘油氧化制备甘油酸的反应。
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