Metal-loaded dehydrogenation catalyst based on carbon material carrier, preparation method and application of metal-loaded dehydrogenation catalyst in catalytic dehydrogenation of organic liquid hydrogen storage material

Abstract

The invention provides a metal-loaded dehydrogenation catalyst based on a carbon material carrier, a preparation method and application of the metal-loaded dehydrogenation catalyst in catalytic dehydrogenation of an organic liquid hydrogen storage material, and belongs to the technical field of catalysts. The catalyst comprises 88.5%-98.5% of a carrier, 0.5%-2.5% of precious metal and 1%-9% of an auxiliary agent. The catalyst can be applied to organic liquid hydrogen storage material reaction, the reaction rate is high, no other by-products exist, the catalyst can be used repeatedly, and the dehydrogenation stability is good. The use amount of the active component noble metal in the catalyst is reduced, and the cost of the catalyst is reduced. According to the invention, a cold plasma technology is utilized, so that a large amount of active component noble metal is effectively anchored at an assistant-carrier interface to generate a large amount of micro-positively charged noble metal particles, strong electron complementarity between the noble metal and the assistant forms a special electronic environment, and the density and fluidity of electrons are improved.

Description

Technical Field

[0001] The present invention relates to the field of catalyst technology, and in particular to a supported metal dehydrogenation catalyst based on a carbon material carrier, a preparation method and application in the catalytic dehydrogenation of an organic liquid hydrogen storage material. Background Art

[0002] As an efficient, green and environmentally friendly renewable secondary energy source, hydrogen energy has become one of the most promising new energy carriers. Hydrogen energy storage technology is a key link in realizing the large-scale application of hydrogen energy. Compared with traditional hydrogen storage methods, liquid organic hydrogen carrier (LOHCs) technology realizes the reversible storage and release of hydrogen through organic compounds, which not only reduces the dependence on special storage conditions, but also reduces the related energy consumption and safety risks. However, LOHCs technology also faces some challenges. The reaction rate of the dehydrogenation process is often low, and the rate of the dehydrogenation reaction will directly affect the application efficiency of hydrogen energy. In order to meet practical applications, organic liquid hydrogen storage technology often needs to rely on specific catalysts.

[0003] In the prior art, CN109701588A discloses a dehydrogenation catalyst and a preparation method thereof, wherein a nitrogen-containing carrier is prepared using a nitride, an active component is introduced by impregnation or precipitation, and the active component is reduced by a low-temperature method to complete the preparation of the dehydrogenation catalyst. The catalyst exhibits good dehydrogenation performance when used in the dehydrogenation reaction of an organic liquid hydrogen storage material, but the preparation of the carrier is cumbersome and expensive; Publication No. CN114436208A discloses a catalytic hydrogen supply system based on an organic liquid and a hydrogen supply method thereof, wherein the catalytic hydrogen supply system involves an organic liquid hydrogen supply material and a hydrogen supply reaction catalyst, wherein the organic liquid hydrogen supply material is composed of a fully hydrogenated benzyltoluene and a decahydronaphthalene organic liquid hydrogen carrier; the hydrogen supply reaction catalyst is a supported metal catalyst, comprising a catalyst carrier and a catalyst active component, but the mass proportion of the catalyst active metal component is 5.0% to 30.0%, and the total mass proportion of the precious metals palladium and platinum is 0.3 to 2.0%, resulting in a high preparation cost. While these technologies have achieved some success in catalytic dehydrogenation using organic liquid hydrogen storage materials, the complex preparation of their supports or the high dosage of active components have reduced cost-effectiveness, limiting their large-scale industrial application. Therefore, designing dehydrogenation catalysts with simple support preparation, low precious metal loading, low cost, and high catalytic activity is an urgent challenge. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a supported metal dehydrogenation catalyst based on a carbon material support, which has simple support preparation, can reduce the loading amount of precious metals, and improve the utilization efficiency of precious metals in the catalyst.

[0005] In order to achieve the above object, the present invention provides a supported metal dehydrogenation catalyst based on a carbon material carrier, wherein the catalyst comprises the following components in percentage by mass:

[0006] Carrier 88.5% to 98.5%, precious metal 0.5% to 2.5%, additive 1% to 9%;

[0007] The carrier is an activated carbon material; the carbon material is C 60 , CNTs, CDs at least one;

[0008] The noble metal is at least one of Pd, Pt, Ru, and Rh;

[0009] The auxiliary agent is at least one of the simple substances or oxides of Zn, Fe, Ti, and Ce.

[0010] 75% to 90% of the noble metal surface carries a slight positive charge and is effectively anchored at the auxiliary agent-carrier interface.

[0011] Preferably, the specific surface area of ​​the catalyst is 150 to 250 m 2 / g, pore volume of 0.60~1.00cm 3 / g, pore size is 10-15nm.

[0012] Preferably, the preparation method of the carrier is:

[0013] (1) mixing an alkali and a carbon material in a dispersant, stirring thoroughly, evaporating, and then calcining under an inert gas at 800° C. for 1 to 2 hours to obtain an alkali-treated carbon material;

[0014] (2) cooling the alkali-treated carbon material, dissolving it in the same dispersant, and adding acid dropwise to obtain an acid-treated carbon material;

[0015] (3) The acid-treated carbon material is washed, dried, and ground to obtain a support.

[0016] More preferably, the base is any one of potassium hydroxide, sodium hydroxide, and ammonia water; the dispersant is any one of water, ethanol, and acetone; the inert gas is any one of nitrogen and argon; and the acid is any one of hydrochloric acid, sulfuric acid, and nitric acid.

[0017] The mass ratio of the alkali, carbon material and dispersant in step (1) is 1-5:1:20;

[0018] The mass ratio of the alkali-treated carbon material, dispersant and acid in step (2) is 1:20:8-10.

[0019] Another object of the present invention is to provide a method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier, comprising the following steps:

[0020] S1, mixing the additive precursor and the carrier in a dispersant, ultrasonicating, stirring, evaporating to dryness, calcining in an inert gas, and cooling to room temperature to obtain an additive-carrier;

[0021] S2, mixing the additive-carrier and the noble metal precursor in a dispersant, stirring, evaporating to dryness, and drying in an oven to obtain a catalyst precursor;

[0022] S3. Putting the catalyst precursor into a cold plasma reactor, introducing reaction gas to fully react, and obtaining the supported metal dehydrogenation catalyst based on the carbon material carrier.

[0023] Preferably, the auxiliary agent precursor in step S1 is an organic salt or an inorganic salt of an auxiliary agent; the dispersant is any one of water, ethanol, and acetone; and the inert gas is any one of nitrogen and argon;

[0024] The ratio of the auxiliary agent precursor, carrier and dispersant is 20-25:170-180:50000;

[0025] The calcination temperature is 450-500°C.

[0026] Preferably, in step S2, the noble metal precursor is an organic salt or an inorganic salt of a noble metal; the dispersant is any one of water, ethanol, and acetone;

[0027] The ratio of the auxiliary agent-carrier, noble metal precursor and dispersant is 95-100:1:1950-2000;

[0028] Preferably, the reaction gas in step S3 is any one of O2, H2, and Ar, and the output voltage of the cold plasma is 80-120V.

[0029] The third object of the present invention is to provide an application of the above-mentioned carbon material-based supported metal dehydrogenation catalyst in the catalytic dehydrogenation reaction of an organic liquid hydrogen storage material;

[0030] The organic liquid hydrogen storage material is any one of perhydronitropropylcarbazole, perhydronitroethylcarbazole, perhydrodibenzyltoluene, perhydro1-methylindole, and perhydro1,2-dimethylindole, or a mixed system formed by multiple thereof.

[0031] Preferably, the temperature of the catalytic dehydrogenation reaction is 100° C. to 400° C., the mass ratio of the catalyst to the organic liquid hydrogen storage material is 1:5 to 5:1, and the reaction time is 0 to 400 min.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The supported metal dehydrogenation catalyst based on the carbon material carrier provided by the present invention can be applied to the reaction of organic liquid hydrogen storage materials, has a fast reaction rate, no other by-products, the catalyst can be used multiple times, and has good dehydrogenation stability. The carrier of the present invention is simple to prepare, and at the same time reduces the usage of the active component noble metal, greatly reducing the cost of the catalyst. The present invention utilizes cold plasma technology to effectively anchor a large amount of active component noble metals at the auxiliary agent-carrier interface, generating a large number of slightly positive noble metal particles. The strong electronic complementarity between the noble metal and the auxiliary agent forms a special electronic environment, which increases the density and mobility of electrons. The slightly positive noble metal particles enhance the dehydrogenation reaction rate, and the auxiliary agent can quickly replenish the consumption generated during the reaction, forming a special synergistic mechanism, thereby enhancing the activity and stability of the catalyst, and making the dehydrogenation reaction more effective and continuous. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the physical adsorption-desorption curve of the carbon material support-based supported metal dehydrogenation catalyst prepared in Example 2;

[0035] Figure 2 This is a pore size distribution diagram of the supported metal dehydrogenation catalyst based on the carbon material support prepared in Example 2;

[0036] Figure 3 This is a TEM morphology of the carbon material-based supported metal dehydrogenation catalyst prepared in Example 2;

[0037] Figure 4 This is a graph showing the relationship between the amount of hydrogen released by the carbon material-based supported metal dehydrogenation catalyst prepared in Example 2 and the dehydrogenation of perhydronitriloylcarbazole;

[0038] Figure 5 This is a graph showing the dehydrogenation cycle stability of the supported metal dehydrogenation catalyst based on a carbon material support prepared in Example 2;

[0039] Figure 6 Comparison chart of ammonia temperature-programmed desorption (NH3-TPD) tests on the catalysts of Examples 2, 5, 6, 7, and 8 (with different CeO2 loadings);

[0040] Figure 7 Comparison chart of hydrogen temperature programmed desorption (H2-TPD) tests on the catalysts of Examples 2, 9, and 10 (treated with cold plasma using different gas sources) and Example 11 (not treated with cold plasma);

[0041] Figure 8This is a graph showing the relationship between the amount of hydrogen released by dehydrogenation of perhydronitriloylcarbazole and the catalysts of Examples 2, 9, and 10 (treated with cold plasma from different gas sources) and Example 11 (not treated with cold plasma). DETAILED DESCRIPTION

[0042] The present invention provides a supported metal dehydrogenation catalyst based on a carbon material carrier, wherein the catalyst comprises the following components in percentage by mass:

[0043] Carrier 88.5% to 98.5%, precious metal 0.5% to 2.5%, additive 1% to 9%;

[0044] The carrier is an activated carbon material; the carbon material is at least one of C60, CNT, and CDs;

[0045] The noble metal is at least one of Pd, Pt, Ru, and Rh;

[0046] The auxiliary agent is at least one of the elements or oxides of Zn, Fe, Ti, and Ce;

[0047] 75% to 90% of the surface of the noble metal carries a slight positive charge and is effectively anchored at the interface between the additive and the carrier; specifically, the slight positive charge is a +2 valence slight positive charge.

[0048] In a specific embodiment of the present invention, the specific surface area of ​​the catalyst is 150 to 250 m 2 / g, pore volume of 0.60~1.00cm 3 / g, pore size is 10-15nm.

[0049] In a specific embodiment of the present invention, the preparation method of the carrier is:

[0050] (1) mixing an alkali and a carbon material in a dispersant, stirring thoroughly, evaporating, and then calcining under an inert gas at 800° C. for 1 to 2 hours to obtain an alkali-treated carbon material;

[0051] (2) cooling the alkali-treated carbon material, dissolving it in the same dispersant, and adding acid dropwise to obtain an acid-treated carbon material;

[0052] (3) The acid-treated carbon material was repeatedly rinsed with deionized water until neutral, dried, and ground to obtain a pore volume of 1 to 1.5 cm 3 / g, a carbon material carrier with a pore size of 10 to 20 nm;

[0053] In a specific embodiment of the present invention, the base is any one of potassium hydroxide, sodium hydroxide, and ammonia water; the dispersant is any one of water, ethanol, and acetone; the inert gas is any one of nitrogen and argon; the acid is any one of hydrochloric acid, sulfuric acid, and nitric acid;

[0054] The mass ratio of the alkali, carbon material and dispersant in step (1) is 4:1:20;

[0055] The mass ratio of the alkali-treated carbon material, dispersant and acid in step (2) is 1:20:8.

[0056] The present invention also provides a method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier, comprising the following steps:

[0057] S1, mixing the auxiliary agent precursor and the carrier in a dispersant, ultrasonicating for 10-15 minutes, magnetically stirring for 3-3.5 hours, evaporating to dryness at 75-85°C, heating to 450-500°C at a rate of 10-13°C / min in an inert gas, and calcining for 2-2.5 hours, and cooling to room temperature to obtain an auxiliary agent-carrier;

[0058] The auxiliary agent precursor is an organic salt or an inorganic salt of the auxiliary agent; the dispersant is any one of water, ethanol, and acetone; the inert gas is any one of nitrogen and argon;

[0059] The ratio of the auxiliary agent precursor, carrier and dispersant is 25:173:50000;

[0060] S2, mixing the additive-carrier and the noble metal precursor in a dispersant, stirring for 10 to 12 hours, evaporating to dryness at 80°C, and directly transferring to an oven after evaporation to dryness at 50 to 100°C for 12 to 24 hours to obtain a catalyst precursor;

[0061] The noble metal precursor is an organic salt or an inorganic salt of a noble metal; the dispersant is any one of water, ethanol, and acetone;

[0062] The ratio of the additive-carrier, noble metal precursor and dispersant is 99:1:1980;

[0063] S3. Place the catalyst precursor into a DBD cold plasma reaction device, introduce the reaction gas at a flow rate of 10 mL / min for 15 minutes, then open the reactor and set the output voltage to 80-120 V, react for 2-3 minutes, cool, and repeat the process 3-4 times to obtain the carbon material carrier-based supported metal dehydrogenation catalyst; the reaction gas is any one of O2, H2, and Ar.

[0064] In a specific embodiment of the present invention, the DBD cold plasma reaction device used includes a cold plasma generator of a CTP-2000K experimental power supply, an OPTIMA 5300DV inductively coupled cold plasma emission spectrometer, and a gas cylinder.

[0065] In a specific embodiment of the present invention, for the auxiliary agent precursor, when the auxiliary agent is Zn, the precursor is one of zinc chloride, zinc sulfate, and zinc nitrate; when the auxiliary agent is Fe, the precursor is one of ferric chloride, ferric sulfate, and ferric nitrate; when the auxiliary agent is Ti, the precursor is one of tetrabutyl titanate, titanium sulfate, and titanium nitrate; when the auxiliary agent is Ce, the precursor is one of cerous chloride, cerous sulfate, and cerous nitrate hexahydrate; the dispersant is one of water, ethanol, and acetone.

[0066] In a specific embodiment of the present invention, for the precious metal precursor, when the precious metal is Pd, the precursor is one of palladium acetate, sodium chloropalladate, and sodium bromopalladate; when the precious metal is Pt, the precursor is one of sodium chloroplatinate, dichlorodiammineplatinum, and potassium pentachloroammineplatinate; when the precious metal is Ru, the precursor is one of ruthenium chloride, ruthenium acetate, and ruthenium nitrate; when the precious metal is Rh, the precursor is one of rhodium chloride, rhodium sulfate, and rhodium nitrate; the dispersant is one of water, hydrochloric acid, and ammonia water.

[0067] The carbon material carrier-based supported metal dehydrogenation catalyst prepared by the present invention is used in the catalytic dehydrogenation reaction of an organic liquid hydrogen storage material. The specific method is: the catalyst and the organic liquid hydrogen storage material are mixed in a mass ratio of 1:5 to 5:1, and the two are reacted at a temperature of 100°C to 400°C for 0 to 400 minutes.

[0068] The organic liquid hydrogen storage material is any one of perhydronitropropylcarbazole, perhydronitroethylcarbazole, perhydrodibenzyltoluene, perhydro1-methylindole, and perhydro1,2-dimethylindole, or a mixed system formed by multiple thereof.

[0069] The present invention will be further described below with reference to the embodiments.

[0070] Example 1

[0071] The preparation method of the carbon material carrier comprises the following steps:

[0072] (1) 4 g of KOH and 1 g of CNT were mixed in 20 mL of deionized water, stirred thoroughly, evaporated to dryness, transferred to a tube furnace, and calcined at 800 °C for 1 h under an Ar atmosphere to obtain an alkali-treated carbon material;

[0073] (2) redissolving the alkali-treated carbon material in 20 mL of deionized water and adding 1 M hydrochloric acid dropwise to obtain an acid-treated carbon material;

[0074] (3) Finally, the solution was rinsed repeatedly with deionized water until neutral, and the average pore volume was 1.22 cm after drying and grinding. 3 / g, CNT support with an average pore size of 16.3nm.

[0075] The vectors in the following examples are all from Example 1.

[0076] Example 2

[0077] A method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier, comprising the following steps:

[0078] S1. 0.125 g of Ce(NO3)3·6H2O and 0.865 g of CNT carrier were added to a beaker, and 250 mL of deionized water was added. The mixture was ultrasonicated for 10 min, magnetically stirred for 3 h, evaporated to dryness at 80 °C, and transferred to a tube furnace. The temperature was increased to 450 °C at a rate of 10 °C / min under N2 atmosphere, maintained for 2 h, and cooled to room temperature to obtain CeO2-CNT.

[0079] S2. Take 0.495g of CeO2-CNT, add 10mL of 1M ammonia water and 1mL of 5mg / mL Na2PdCl4 into a beaker, continue stirring for 12h, evaporate to dryness at 80℃, transfer to an oven after evaporation, and dry at 70℃ for 24h to obtain a catalyst precursor after complete drying;

[0080] S3. Spread the catalyst precursor flatly in the DBD cold plasma reaction device, cover it with a sealing cover, and introduce Ar at a flow rate of 10 mL / min for 15 minutes. Open the reactor and set the output voltage to 100 V. React for 2 minutes. After closing the reactor, stir the sample evenly and spread it flat in the reactor again. Cool it for 3 minutes and react again. Repeat the process three times to obtain a supported metal dehydrogenation based on a carbon material carrier, recorded as Pd / 5% CeO2-C-Ar.

[0081] The theoretical loading amount of the catalyst precious metal Pd is 1 wt %, and the loading amount of the auxiliary agent CeO 2 is 5 wt %.

[0082] The obtained catalyst was pre-treated by degassing at 200°C, 300 μmHg, and 6 h, and then nitrogen physical adsorption and desorption was performed using a Micromeritics ASAP 2460 in a liquid nitrogen bath at -196°C.

[0083] Physical adsorption-desorption curve of the catalyst Figure 1 As shown, the pore size distribution of the catalyst is as follows Figure 2 As shown, from Figure 1 and Figure 2 It can be seen that the specific surface area of ​​the Pd / 5% CeO2-C-Ar catalyst treated with cold plasma is 160-180 m 2 / g, pore volume is 0.60~0.80cm 3 / g, the pore size is 10-12nm. The TEM characterization results of the catalyst are as follows Figure 3As shown, it can be seen that Pd is evenly distributed on CeO2-CNT.

[0084] Example 3

[0085] The catalyst prepared in Example 2 was used to dehydrogenate the organic liquid hydrogen storage material in the following manner:

[0086] The organic liquid hydrogen storage material is fully hydrogenated aziridine carbazole, the reaction temperature is 180℃, the ratio of catalyst to fully hydrogenated aziridine carbazole is 1:5, and complete dehydrogenation is achieved within 240 minutes, with a dehydrogenation amount of about 5.4wt%. Figure 4 shown.

[0087] Example 4

[0088] The supported metal dehydrogenation catalyst based on the carbon material carrier prepared in Example 2 was used to carry out cyclic dehydrogenation of the organic liquid hydrogen storage material, and the method was as follows:

[0089] The organic liquid hydrogen storage material is fully hydrogenated aziridine carbazole. The reaction temperature is 180°C. The ratio of catalyst to fully hydrogenated aziridine carbazole is 1:5. The dehydrogenation is carried out for 8 cycles. The dehydrogenation data are as follows: Figure 5 As shown, from Figure 5 It can be seen that the dehydrogenation performance still maintains a high hydrogen release amount after 8 cycles.

[0090] Examples 5 to 8

[0091] According to the method of Example 2, the amounts of Ce(NO3)3·6H2O and CNT in step S1 were adjusted to obtain catalysts with CeO2 loadings of 1%, 3%, 7%, and 9%, respectively.

[0092] Since CeO2 itself has a low specific surface area, as the introduced CeO2 content increases, the specific surface area, pore volume and pore size of the corresponding catalyst decrease. The specific surface area of ​​the Pd / 1% CeO2-C-Ar catalyst is 200-205m 2 / g, pore volume is 0.75~0.80cm 3 / g, and the pore size is 20-25nm.

[0093] The catalysts prepared in Examples 2, 5, 6, 7, and 8 were subjected to Raman spectroscopy, inductively coupled plasma emission spectroscopy, and carbon monoxide pulse chemical adsorption tests. The results are shown in Table 1.

[0094] Table 1

[0095]

[0096]

[0097] As shown in Table 1, after introducing low CeO2 loadings (1, 3, and 5 wt%), the Pd metal particle size gradually decreases with increasing CeO2 content. However, further increasing the CeO2 content increases the Pd metal particle size to approximately 3.4 nm. This indicates that excessive CeO2 loading results in more active metal Pd being deposited directly on the CeO2, resulting in a lower degree of aggregation during the reduction preparation process.

[0098] Example 9

[0099] A method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier, the steps are as described in Example 1.

[0100] The difference is that the reaction gas introduced in step S4 of Example 9 is O2. The catalyst is recorded as Pd / 5% CeO2-C-O2, and its specific surface area is 200-230m 2 / g, pore volume is 0.60~1.00cm 3 / g, and the pore size is 10-15nm.

[0101] Example 10

[0102] A method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier, the steps are as described in Example 1.

[0103] The difference is that the reaction gas introduced in step S4 of Example 10 is H2. The catalyst is recorded as Pd / 5% CeO2-C-H2, and its specific surface area is 160-170m 2 / g, pore volume is 0.50~0.75cm 3 / g, and the pore size is 10-12nm.

[0104] Example 11

[0105] A method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier, the steps are as described in Example 1.

[0106] The difference is that step S4 of Example 11 does not use cold plasma treatment, but a conventional thermal reduction method is used, specifically as follows: the catalyst precursor powder is transferred to a tube furnace, heated to 240°C at a rate of 5°C / min under a 10% H2 / Ar atmosphere, maintained for 2 hours, with a mixed gas flow rate of 70 mL / min, and then ground to obtain a catalyst after cooling. The catalyst is denoted as Pd / 5% CeO2-C, and has a specific surface area of ​​200-235 m 2 / g, pore volume is 0.50~0.65cm 3 / g, and the pore size is 8-10nm.

[0107] The catalysts prepared in Examples 2, 9, 10, and 11 were analyzed by X-ray photoelectron spectroscopy (XPS). All data were calibrated using the binding energy of C1s (284.80 eV). The data obtained are shown in Table 2:

[0108] Table 2

[0109]

[0110]

[0111] As can be seen from Table 2, compared with the catalyst treated with cold plasma, the catalyst prepared by conventional thermal reduction method (Pd / 5% CeO2-C) cannot produce a large amount of slightly positive noble metal particles Pd (II), which limits the progress of the dehydrogenation reaction; while the catalyst treated with Ar gas cold plasma (Pd / 5% CeO2-C-Ar) produces more oxygen vacancies on the CeO2 surface, constructs a large number of CeO2-C interfaces, and effectively anchors more active component noble metals at the interface, producing a large number of slightly positive noble metal particles Pd (II), promoting the desorption of the final dehydrogenation product, and making the catalytic reaction more efficient and continuous.

[0112] Example 12

[0113] The catalysts prepared in Examples 2, 5, 6, 7, and 8 were subjected to ammonia temperature-programmed desorption (NH3-TPD) treatment, and the specific steps were as follows:

[0114] S1 impurity removal: Place about 50 mg of the catalyst under high-purity Ar conditions, heat it from 50°C to 200°C at a heating rate of 10°C / min and continue for 1 hour to remove impurities from the catalyst;

[0115] After the S2 adsorption and impurity removal process is completed and the temperature is cooled to room temperature, the atmosphere is replaced with a NH3 / Ar mixed gas with an NH3 content of 10%, and the catalyst is allowed to fully adsorb for 1 hour at room temperature;

[0116] S3 was desorbed and the catalyst was heated to 800°C at a heating rate of 10°C / min in a high-purity Ar atmosphere, and the NH3 content in the tail gas was recorded by TCD.

[0117] NH3-TPD uses NH3 as a molecular probe to study the acidic properties of catalysts. Figure 6As shown in the figure, the medium-strong acid sites at 200-400°C are provided by the CeO2-C interface. As the CeO2 content increases, the content of medium-strong acid sites in the catalyst first gradually increases and then disappears directly. This shows that at low loadings (1, 3, 5wt%), the CeO2-C interface gradually increases, allowing more surface slightly positively charged Pd(II) to fall at the interface. However, when the CeO2 loading reaches 7wt%, the CeO2 is oversaturated, the CeO2-C interface disappears, and the Pd(II) no longer falls at the interface, but directly falls on the CeO2 surface, which is not conducive to the dehydrogenation reaction.

[0118] Example 13

[0119] The catalysts prepared in Examples 2, 9, 10, and 11 were subjected to hydrogen temperature-programmed desorption (H2-TPD) treatment, and the specific steps were the same as those in Example 12;

[0120] The difference is that the atmosphere in S2 is replaced with a H2 / Ar mixed gas with a H2 content of 10%, and the catalyst is allowed to fully adsorb at room temperature for 1 hour; and the H2 content in the exhaust gas is recorded by TCD in S3.

[0121] H2-TPD uses H2 as a molecular probe to study the adsorption-dissociation ability of active component noble metals on hydrogen species. Figure 7 As shown in the figure, the catalyst that has not been treated with cold plasma has only one desorption peak at around 100°C, which is attributed to the adsorption of hydrogen on the weak adsorption sites on the surface. After being treated with cold plasma in different atmospheres, there are two desorption peaks at around 100°C and 280°C. The former corresponds to the hydrogen adsorption on the weak adsorption sites on the surface, and the latter is the hydrogen adsorbed by the slightly positively charged Pd(II) on the surface located at the CeO2-C interface. Pd / 5%CeO2-C-Ar has the highest desorption peak among all catalysts in the higher temperature range (300-500°C) and has a stronger adsorption effect on hydrogen, which means that more slightly positively charged Pd(II) on the surface falls on the CeO2-C interface, thereby promoting the continuous and efficient dehydrogenation reaction.

[0122] Example 14

[0123] The catalysts prepared in Examples 2, 9, 10 and 11 were used for dehydrogenation of organic liquid hydrogen storage materials.

[0124] The organic liquid hydrogen storage material is perhydronitriloylcarbazole, the reaction temperature is 180°C, and the ratio of catalyst to perhydronitriloylcarbazole is 1:5. Figure 8 Pd / 5%CeO2-C-Ar showed the highest dehydrogenation rate, with a hydrogen release of 5.34 wt% at 360 min, achieving complete hydrogen release.

[0125] Comparative Example 1

[0126] According to the preparation method of Example 2, the CeO2-CNT prepared in Example 1 was used to replace S2 as the carrier to prepare the catalyst. The catalyst was recorded as Pd / C-Ar and its specific surface area was 250-300m 2 / g, pore volume is 0.90~1.20cm 3 / g, and the pore size is 13-16nm.

[0127] experiment

[0128] Surface charge detection was performed on the noble metal element Pd, the catalysts prepared in Examples 2, 5, 6, 7, 8, 9, 10, 11 and Comparative Example 1, and the results of the +2-valent slightly positive charge content are shown in Table 3.

[0129] Table 3

[0130]

[0131] As can be seen from Table 3, both the CeO2 additive and cold plasma atmosphere treatment can increase the content of slightly positively charged Pd(II). The Pd / 5% CeO2-C-Ar catalyst of Example 2 has the highest slightly positive charge content and is effectively anchored at the CeO2-CNT interface. The slightly positive noble metal particles Pd(II) enhance the dehydrogenation reaction rate, and the CeO2 additive can quickly replenish the consumption generated during the reaction. The synergistic effect of the two greatly enhances the activity and cyclic stability of the catalyst, promoting the rapid and complete dehydrogenation reaction.

[0132] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A supported metal dehydrogenation catalyst based on a carbon material carrier, characterized in that: The following ingredients are included in mass percentage: Carrier 88.5%~98.5%, precious metal 0.5%~2.5%, additive 1%~9%; The carrier is an activated carbon material; the carbon material is C 60 , CNTs, CDs; The noble metal is at least one of Pd, Pt, Ru and Rh; The auxiliary agent is at least one of the simple substance or oxide of Zn, Fe, Ti, and Ce; 75% to 90% of the noble metal surface carries a slight positive charge and is effectively anchored at the auxiliary agent-carrier interface.

2. The supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 1, characterized in that: The specific surface area of ​​the catalyst is 150 to 250 m 2 / g, pore volume is 0.60~1.00cm 3 / g, pore size is 10-15nm.

3. The supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 1, characterized in that: The preparation method of the carrier is: (1) mixing an alkali and a carbon material in a dispersant, stirring thoroughly, evaporating, and then calcining in an inert gas at 800° C. for 1 to 2 hours to obtain an alkali-treated carbon material; (2) cooling the alkali-treated carbon material, dissolving it in the same dispersant and adding acid dropwise to obtain an acid-treated carbon material; (3) Washing, drying and grinding the acid-treated carbon material to obtain a carrier.

4. The supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 3, characterized in that: The base is any one of potassium hydroxide, sodium hydroxide, and ammonia water; the dispersant is any one of water, ethanol, and acetone; the inert gas is any one of nitrogen and argon; the acid is any one of hydrochloric acid, sulfuric acid, and nitric acid; In step (1), the mass ratio of the alkali, the carbon material and the dispersant is 1-5:1:20; In step (2), the mass ratio of the alkali-treated carbon material, dispersant and acid is 1:20:8-10.

5. The method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 1, characterized in that: The following steps are involved: S1, mixing the auxiliary agent precursor and the carrier in a dispersant, ultrasonicating, stirring, evaporating to dryness, calcining in an inert gas, and cooling to room temperature to obtain an auxiliary agent-carrier; S2, mixing the additive-carrier and the noble metal precursor in a dispersant, stirring, evaporating and drying in an oven to obtain a catalyst precursor; S3, placing the catalyst precursor into a cold plasma reactor, introducing a reaction gas to fully react, and obtaining the supported metal dehydrogenation catalyst based on the carbon material carrier.

6. The method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 5, characterized in that: Step S1: the additive precursor is an organic salt or an inorganic salt of the additive; the dispersant is any one of water, ethanol, and acetone; the inert gas is any one of nitrogen and argon; The mass ratio of the auxiliary agent precursor, the carrier and the dispersant is 20-25:170-180:50000; The calcination temperature is 450-500°C.

7. The method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 5, characterized in that: In step S2, the noble metal precursor is an organic salt or an inorganic salt of a noble metal; the dispersant is any one of water, ethanol, and acetone; The ratio of the auxiliary agent-carrier, the noble metal precursor and the dispersant is 95-100:1:1950-2000.

8. The method for preparing a supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 5, characterized in that: In step S3, the reaction gas is any one of O2, H2, and Ar; and the output voltage of the cold plasma is 80 to 120V.

9. The use of the supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 1, characterized in that: Application of the catalyst in catalytic dehydrogenation reaction of organic liquid hydrogen storage materials; The organic liquid hydrogen storage material is any one of perhydrogenated aziridine carbazole, perhydrogenated aziridine ethyl carbazole, perhydrogenated dibenzyl toluene, perhydrogenated 1-methyl indole, and perhydrogenated 1,2-dimethyl indole, or a mixed system formed by multiple thereof.

10. The use of a supported metal dehydrogenation catalyst based on a carbon material carrier according to claim 9, characterized in that: The temperature of the catalytic dehydrogenation reaction is 100° C. to 400° C., the mass ratio of the catalyst to the organic liquid hydrogen storage material is 1:5 to 5:1, and the reaction time is 0 to 400 minutes.

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