Methanoic acid hydrogen production catalyst as well as preparation method and application thereof

Abstract

The invention discloses a formic acid hydrogen production catalyst and a preparation method and application thereof, and relates to the technical field of formic acid hydrogen production catalyst methods. In an inert gas environment and under a certain pressure, metal wires of palladium and gold elements are heated and fused under the action of current, and the fused metal wires start to discharge under the action of high voltage at the moment of current interruption, so that the fused metal wires become metal vapor in the discharge process, and the metal vapor is separated from the metal wires. The metal nano ultrafine powder is formed under the action of inert gas, the catalyst has good catalytic activity, selectivity and stability, gas-phase formic acid is catalyzed to produce hydrogen at 40 DEG C, the conversion rate reaches 98%, the selectivity reaches 96.3%, the reaction hydrogen production rate is 320 mmol / (g.h), and the catalyst has wide application prospects and is suitable for industrial production. The formic acid hydrogen production catalyst is prepared with low cost and high efficiency.

Description

Technical Field

[0001] The present application relates to the field of catalyst technology, and in particular to a formic acid hydrogen production catalyst and a preparation method and application thereof. Background Art

[0002] With the rapid development of the global economy, traditional fossil energy has caused serious environmental pollution problems. It is urgent to change the dependence on the traditional fossil energy system and establish a green energy structure. The shift of energy structure to high energy density "zero emission" energy carrier - hydrogen has become a hot topic in current research.

[0003] At present, the widespread application of hydrogen energy faces an important bottleneck problem, namely the difficulty in safe and efficient storage and transportation of hydrogen. The main storage and transportation process of hydrogen is to transport gaseous or liquid hydrogen through special high-pressure storage tanks or pipelines. Although the technology is relatively mature, it requires specific low temperature or high pressure conditions, which not only increases energy consumption and costs, but also poses considerable challenges to safety.

[0004] Formic acid (HCOOH) is the simplest hydrogen-containing monobasic organic carboxylic acid. The Gibbs free energy of the formic acid decomposition reaction to produce hydrogen at room temperature is negative, which means it is thermodynamically favorable. Compared with other hydrogen carriers (such as methanol, ammonia, etc.), which all rely on high temperature, high pressure and catalyst-catalyzed reaction conditions to decompose and produce hydrogen, formic acid can be efficiently decomposed into hydrogen and carbon dioxide at room temperature and pressure with the help of a catalyst. Therefore, formic acid hydrogen production is one of the most feasible ways to produce hydrogen at this stage.

[0005] Photocatalytic hydrogen production from formic acid is a current research hotspot, and the preparation of efficient catalysts using simple and fast methods is of utmost importance. Summary of the invention

[0006] The embodiments of the present application provide a formic acid hydrogen production catalyst and a preparation method and application thereof, thereby solving the technical problems in the prior art of preparing formic acid hydrogen production catalysts, such as complex preparation process, low hydrogen production efficiency of the prepared catalyst, and low proportion of conversion products. The formic acid hydrogen production catalyst is prepared at low cost and with high efficiency, and is applied to catalytic gas-phase formic acid hydrogen production.

[0007] In a first aspect, an embodiment of the present application provides a formic acid hydrogen production catalyst, wherein the formic acid hydrogen production catalyst is a composite palladium / gold bimetallic nanoparticle obtained by mixing palladium nano-ultrafine powder and gold nano-ultrafine powder in a ratio of 1:3 to 3:1.

[0008] In the second aspect, an embodiment of the present application provides a method for preparing a formic acid hydrogen production catalyst, comprising: step 1: placing a palladium wire and a gold wire into a reactor respectively, and connecting the two ends of the palladium wire and the gold wire to the two ends of a power line respectively, evacuating the interior of the reactor, and filling the reactor with an inert gas for pressurization; step 2: applying electricity and heating the palladium wire / gold wire until a melting point appears on the palladium wire / gold wire, and the melting point of the palladium wire / gold wire begins to discharge under the action of high voltage electricity, and the palladium element / gold element at the melting point generates palladium vapor / gold vapor during the discharge process, and the palladium vapor / gold vapor is condensed to obtain palladium nano-ultrafine powder / gold nano-ultrafine powder; step 3: mixing the palladium nano-ultrafine powder and the gold nano-ultrafine powder to obtain composite palladium / gold bimetallic nanoparticles.

[0009] In combination with the second aspect, in a possible implementation, the palladium wire in step 1 has a length of 20 mm and a diameter of 0.4 mm; the gold wire has a length of 20 mm and a diameter of 0.4 mm.

[0010] In combination with the second aspect, in a second possible implementation, in step 1, the interior of the reactor is evacuated to a vacuum degree of 2Pa-5Pa.

[0011] In combination with the second aspect, in a third possible implementation, in step 1, an inert gas is filled into the interior of the reactor to pressurize the reactor until the internal pressure of the reactor reaches 0.3 MPa-0.5 MPa.

[0012] In combination with the second aspect, in a fourth possible implementation, the voltage of the high voltage in step 2 is 2×10 4 V-2×10 5 V.

[0013] In combination with the second aspect, in a fifth possible implementation manner, in step 3, the mixing ratio of palladium nano-ultrafine powder and gold nano-ultrafine powder is palladium nano-ultrafine powder: gold nano-ultrafine powder=1:1.

[0014] In a third aspect, an embodiment of the present application provides a formic acid hydrogen production catalyst as described in the first aspect for decomposing formic acid to produce hydrogen.

[0015] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0016] The embodiment of the present application adopts the method of passing electricity through palladium wire and gold wire in a high-pressure, inert gas environment to produce a melting point, which explodes at the melting point to generate palladium vapor and gold vapor, and obtains palladium nano-ultrafine powder and gold nano-ultrafine powder after condensation. The palladium nano-ultrafine powder and the gold nano-ultrafine powder are mixed to obtain composite palladium / gold bimetallic nanoparticles, and the composite palladium / gold bimetallic nanoparticles are applied to the process of hydrogen production from formic acid, thereby effectively solving the technical problems of the method for preparing formic acid hydrogen production catalyst in the prior art, such as complex preparation process, low hydrogen production efficiency of the prepared catalyst, and low proportion of conversion products, thereby achieving the technical effect of preparing formic acid hydrogen production catalyst at low cost and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A flow chart of a method for preparing a formic acid hydrogen production catalyst provided in an embodiment of the present application;

[0019] Figure 2 TEM image of composite palladium / gold bimetallic nanoparticles provided in the examples of the present application;

[0020] Figure 3 A comparison chart of the selectivity of hydrogen produced in the process of producing hydrogen from formic acid by samples prepared in different embodiments of the present application;

[0021] Figure 4 A comparison chart of the conversion rates of formic acid in the process of hydrogen production from formic acid using samples prepared in different embodiments of the present application;

[0022] Figure 5 A comparison chart of the generation rates of hydrogen generated by samples prepared in different embodiments provided in the present application when used in the process of producing hydrogen from formic acid. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The embodiment of the present application provides a formic acid hydrogen production catalyst, which is a composite palladium / gold bimetallic nanoparticle obtained by mixing palladium nano-ultrafine powder and gold nano-ultrafine powder in a ratio of 1:3 to 3:1. In the process of preparing hydrogen by decomposing formic acid, the formic acid hydrogen production catalyst provided in the embodiment of the present application is used to catalyze the decomposition process of formic acid to accelerate the rate of hydrogen production, improve the efficiency of hydrogen production, and increase the proportion of conversion products.

[0025] The present application provides a method for preparing a formic acid hydrogen production catalyst, and the practical application method is the explosion method commonly used in chemistry. The specific preparation method process is as follows: Figure 1 As shown, it includes steps 1 to 3.

[0026] Step 1: Place the palladium wire and the gold wire into the reactor respectively, and connect the two ends of the palladium wire and the gold wire to the two ends of the power line respectively, evacuate the inside of the reactor, and fill the reactor with inert gas to pressurize it.

[0027] Step 2: The palladium wire / gold wire is electrically heated until a melting point appears on the palladium wire / gold wire. The melting point of the palladium wire / gold wire begins to discharge under the action of high voltage electricity. The palladium element / gold element at the melting point generates palladium vapor / gold vapor during the discharge process. The palladium vapor / gold vapor is condensed to obtain palladium nano-ultrafine powder / gold nano-ultrafine powder.

[0028] Step 3: Mix palladium nano-ultrafine powder and gold nano-ultrafine powder to obtain composite palladium / gold bimetallic nanoparticles.

[0029] The TEM image of the prepared composite palladium / gold bimetallic nanoparticles is shown in Figure 2 shown.

[0030] In the embodiment of the present application, a palladium wire and a gold wire are heated by electric current in a closed high-pressure environment filled with inert gas, so that the palladium wire and the gold wire explode instantly at the melting point, and the explosion products are mixed to obtain composite palladium / gold bimetallic nanoparticles, which are the catalysts required in the process of hydrogen production from formic acid. The preparation process of the formic acid hydrogen production catalyst is relatively simple and has high preparation efficiency. After the obtained product is mixed with formic acid, hydrogen is generated, and the hydrogen production process has high hydrogen selectivity, high formic acid conversion rate, and fast hydrogen production rate.

[0031] It should be noted that in the present application, the inert gas may be selected from helium, neon, argon and other inert gases that are not easily involved in the reaction.

[0032] Although the present application provides method operation steps as described in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in this embodiment is only one way of executing the order of many steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order of the method shown in this embodiment or the accompanying drawings or in parallel.

[0033] In the embodiments of the present application, there are no excessive restrictions on the preparation order of palladium nano-ultrafine powder and gold nano-ultrafine powder.

[0034] According to the actual needs, the technicians in this field can first prepare palladium nano-ultrafine powder, remove the palladium nano-ultrafine powder from the reactor, then prepare gold nano-ultrafine powder, and finally mix the palladium nano-ultrafine powder and the gold nano-ultrafine powder in other containers in proportion to obtain composite palladium / gold bimetallic nanoparticles. Or first prepare palladium nano-ultrafine powder, keep the palladium nano-ultrafine powder in the reactor, and prepare gold nano-ultrafine powder based on the same preparation steps. In the process of preparing gold nano-ultrafine powder, the gold element explodes and collides with the palladium nano-ultrafine powder in the reactor to obtain composite palladium / gold nanoparticles.

[0035] In the present application, the performance of the formic acid hydrogen production catalyst obtained based on the method for preparing the formic acid hydrogen production catalyst mentioned in the embodiments of the present application in the formic acid hydrogen production process will change with the changes in the vacuum degree, the pressurization pressure value, and the voltage of the high voltage, as specifically described in Examples 1 and 2.

[0036] Example 1

[0037] Take a palladium wire with a length of 20 mm and a diameter of 0.4 mm and connect it to both ends of the power line, and put it into the reactor. The reactor is a closed container used to isolate from the outside world, and should have at least one gas port, and the gas port can be closed.

[0038] The reactor was evacuated using a vacuum pump to a vacuum degree of 2 Pa, and argon gas was used to inflate the reactor and pressurize it to 0.5 MPa.

[0039] The voltage applied to the palladium wire is 4×10 4 The high voltage of 10V makes the palladium wire heated under the action of the current, and the palladium wire will melt at a certain point, which is the melting point. At the moment of melting, the two ends of the palladium wire at the melting point begin to discharge, causing the palladium metal at the melting point to explode and obtain palladium vapor. Under the protection of inert gas, the gaseous palladium vapor condenses to obtain palladium nano-ultrafine powder.

[0040] Similarly, the palladium wire is replaced with a gold wire, and the gold wire is subjected to the same operation to obtain gold nano-ultrafine powder.

[0041] The palladium nano-ultrafine powder and the gold nano-ultrafine powder are mixed in a ratio of 1:1 to obtain composite palladium / gold bimetallic nanoparticles.

[0042] 10 mg of composite palladium / gold bimetallic nanoparticles were taken and placed in a gas phase reactor, and the reaction temperature was controlled at 40° C. by a constant temperature water bath.

[0043] 10 μL (265.217 umol) of formic acid was vaporized and added into a gas phase reactor. Formic acid reacted with composite palladium / gold bimetallic nanoparticles to obtain a reaction gas. After measurement, the selectivity of hydrogen was 83.3%, the conversion rate of formic acid was 91.5%, and the generation rate of hydrogen during the reaction was 240 mmol / (g·h).

[0044] Example 2

[0045] Take a palladium wire with a length of 20 mm and a diameter of 0.4 mm and connect it to both sides of the power line, and put it into the reactor.

[0046] The reactor was evacuated using a vacuum pump to a vacuum degree of less than 5 Pa, and argon gas was used to inflate the reactor and pressurize it to 0.3 MPa.

[0047] A voltage of 1×10 5 The high voltage of 10V makes the palladium wire heated under the action of the current, and the palladium wire will melt at a certain point, which is the melting point. At the moment of melting, the two ends of the palladium wire at the melting point begin to discharge, causing the palladium metal at the melting point to explode and obtain palladium vapor. Under the protection of inert gas, the gaseous palladium vapor condenses to obtain palladium nano-ultrafine powder.

[0048] Similarly, the same operation is performed on the gold wire to obtain gold nano-ultrafine powder.

[0049] The palladium nano-ultrafine powder and the gold nano-ultrafine powder are mixed in a palladium ratio of 1:1 to obtain composite palladium / gold bimetallic nanoparticles.

[0050] 10 mg of composite palladium / gold bimetallic nanoparticles were taken and placed in a gas phase reactor, and the reaction temperature was controlled at 40° C. by a constant temperature water bath.

[0051] 10 μL (265.217 umol) of formic acid was vaporized and added into a gas phase reactor. Formic acid reacted with composite palladium / gold bimetallic nanoparticles to obtain a reaction gas. After measurement, the selectivity of hydrogen was 96.3%, the conversion rate of formic acid was 98%, and the generation rate of hydrogen during the reaction was 320 mmol / (g·h).

[0052] Figure 3It is a comparison chart of the selectivity of hydrogen produced by the sample prepared in Example 1 (ie, composite palladium / gold bimetallic nanoparticles) and the sample prepared in Example 2 in the process of producing hydrogen from formic acid.

[0053] exist Figure 3 The vacuum degree of the reaction container reached 2 Pa, and then argon was filled into the reaction container to pressurize it to 0.5 MPa, and a voltage of 4×10 4 V, the selectivity of the hydrogen produced in the process of hydrogen production from formic acid reached 83.3%; the reaction container was evacuated to below 5 Pa, then filled with argon and pressurized to 0.3 MPa, and a voltage of 1×10 5 The sample of Example 2 prepared by a high voltage of 1.5 V has a selectivity of 96.3% for the hydrogen produced in the process of producing hydrogen from formic acid.

[0054] Figure 4 This is a comparison chart of the conversion rates of formic acid in the process of hydrogen production from formic acid between the sample prepared in Example 1 provided in the present application (i.e., composite palladium / gold bimetallic nanoparticles) and the sample prepared in Example 2.

[0055] exist Figure 4 The sample of Example 1 has a formic acid conversion rate of 91.5% in the process of producing hydrogen from formic acid; and the sample of Example 2 has a formic acid conversion rate of 98% in the process of producing hydrogen from formic acid.

[0056] Figure 5 This is a comparison chart of the generation rates of hydrogen generated by the sample prepared in Example 1 (i.e., composite palladium / gold bimetallic nanoparticles) and the sample prepared in Example 2 during the hydrogen production process from formic acid provided in the present application.

[0057] exist Figure 5 In the process of producing hydrogen from formic acid, the sample of Example 1 has a hydrogen production rate of 240 mmol / (g·h), while the sample of Example 2 has a hydrogen production rate of 320 mmol / (g·h).

[0058] The present application illustrates the technical concept of the present application through the above-mentioned embodiments, but the present application is not limited to the above-mentioned embodiments, that is, it does not mean that the present application must rely on the above-mentioned embodiments to be implemented. Technical personnel in the relevant technical field should understand that any improvement of the present application, equivalent replacement of individual raw materials of the product of the present application and addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present application.

[0059] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A formic acid hydrogen production catalyst, characterized in that The formic acid hydrogen production catalyst is a composite palladium / gold bimetallic nanoparticle obtained by mixing palladium nano-ultrafine powder and gold nano-ultrafine powder in a ratio of 1:3 to 3:

1.

2. A method for preparing a formic acid hydrogen production catalyst, characterized in that: include: Step 1: Place a palladium wire and a gold wire into a reactor respectively, and connect the two ends of the palladium wire and the gold wire to the two ends of a power line respectively, evacuate the interior of the reactor, and fill the reactor with an inert gas to pressurize the interior; Step 2: The palladium wire / gold wire is electrically heated until a melting point appears on the palladium wire / gold wire, and the melting point of the palladium wire / gold wire begins to discharge under the action of high voltage electricity, and the palladium element / gold element at the melting point generates palladium vapor / gold vapor during the discharge process, and the palladium vapor / gold vapor is condensed to obtain palladium nano-ultrafine powder / gold nano-ultrafine powder; Step 3: Mix palladium nano-ultrafine powder and gold nano-ultrafine powder to obtain composite palladium / gold bimetallic nanoparticles.

3. The method according to claim 2, characterized in that The length of the palladium wire in step 1 is 20 mm and the diameter is 0.4 mm; The length of the gold wire is 20 mm and the diameter is 0.4 mm.

4. The method according to claim 2, characterized in that: In the step 1, the interior of the reactor is evacuated to a vacuum degree of 2Pa-5Pa.

5. The method according to claim 2, characterized in that: In step 1, an inert gas is charged into the reactor to pressurize it until the internal pressure of the reactor reaches 0.3 MPa-0.5 MPa.

6. The method according to claim 2, characterized in that The voltage of the high voltage in step 2 is 2×10 4 V-2×10 5 V.

7. The method according to claim 2, characterized in that In the step 3, the mixing ratio of palladium nano-ultrafine powder and gold nano-ultrafine powder is palladium nano-ultrafine powder: gold nano-ultrafine powder=1:

1.

8. The formic acid hydrogen production catalyst as claimed in claim 1 is used for decomposing formic acid to produce hydrogen.

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