Preparation method of hydrogen isotope catalytic exchange hydrophilic catalyst
By introducing LiF into the catalyst, the physical adsorption capacity of hydrogen is increased, the problem of low catalyst efficiency at low temperature or high hydrogen flow rates is solved, and efficient hydrogen isotope catalytic exchange is achieved.
Patent Information
- Application Number
- CN202410078771.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-19
- Publication Date
- 2025-07-22
AI Technical Summary
The existing hydrogen isotope catalytic exchange catalysts are inefficient at low temperatures or high hydrogen flow rates and have weak mass transfer processes, which limits their application.
LiF is introduced into the catalyst to increase the physical adsorption capacity of the catalyst to hydrogen and promote the mass transfer process.
The catalytic efficiency of the catalyst at low temperature and high hydrogen flow rate is significantly improved, and efficient hydrogen isotope catalytic exchange is achieved.
Smart Images
Figure CN120346818A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a preparation method of a platinum-based hydrogenophilic catalyst, and also relates to the application of the prepared catalyst in hydrogen isotope catalytic exchange. It belongs to the technical field of the preparation and application of heterogeneous reaction catalysts. Background Art
[0002] The utilization of nuclear energy has great potential in establishing a sustainable energy infrastructure. However, the operation of nuclear power plants will generate a large amount of circulating water containing hydrogen isotopes (deuterium and tritium). Due to its harmful effects on human health and the environment, it is crucial to effectively treat this circulating water. Electrolysis and rectification are the main methods for enriching hydrogen isotopes. However, these methods have obvious disadvantages such as high equipment costs, high energy consumption, and limited separation factors, which greatly limit their practical applications. In this context, hydrogen isotope catalytic exchange is considered a promising method for treating circulating water due to its advantages such as low energy consumption, high safety, simple operation, and high separation coefficient.
[0003] Due to the thermodynamic limitations at low temperatures, low efficiency remains a daunting challenge. At the same time, when the hydrogen flow rate is high, due to the shorter contact time between the reactants and the catalyst, the mass transfer becomes weaker, or the catalytic efficiency drops significantly, which limits the application of hydrogen isotope catalytic exchange. Therefore, it is necessary to develop highly efficient catalysts at low temperatures and high flow rates.
[0004] In hydrogen isotope catalytic exchange, the adsorption and activation of hydrogen on platinum are key steps. Therefore, it is very necessary to improve the adsorption capacity of the catalyst for hydrogen and promote the mass transfer process. Currently, some studies have introduced hydrogenophilic components such as transition metal oxides into the catalyst, but the transition metal oxides have chemical adsorption for hydrogen, which is not conducive to the diffusion of hydrogen on the catalyst surface. Therefore, increasing the physical adsorption capacity of the catalyst for hydrogen is the key to solving these problems. Summary of the Invention
[0005] The technical problem to be solved by the present invention is, aiming at the problem of low efficiency of the catalyst for hydrogen isotope catalytic exchange at low temperatures or high hydrogen flow rates, by introducing LiF into the catalyst to increase the physical adsorption capacity of the catalyst for hydrogen, thereby increasing the concentration of reactants on the catalyst surface and strengthening the mass transfer process of hydrogen, so that the catalytic efficiency has been greatly improved.
[0006] The present invention is realized by the following technical solutions: By introducing LiF into the catalyst, the present invention increases the adsorption capacity of the catalyst for hydrogen, thereby promoting the mass transfer process of hydrogen and greatly improving the catalytic efficiency of the catalyst for hydrogen isotope catalytic exchange at low temperatures and high hydrogen flow rates.
[0007] Preparation method of platinum-based catalyst, preparing the catalyst according to the following steps: S1: Disperse a certain proportion of catalyst support and LiF into a certain amount of methanol, heat and stir in a water bath until the methanol completely volatilizes, obtaining a LiF-doped catalyst support; S2: Disperse the LiF-doped catalyst support into water, then add a certain amount of chloroplatinic acid aqueous solution, and stir to obtain a uniformly dispersed aqueous solution; S3: Place the uniformly dispersed aqueous solution under a mercury lamp for reduction for a period of time, then filter by suction and vacuum dry to obtain the catalyst solid powder.
[0008] Further, the catalyst support in step S1 is carbon, alumina or Ti3AlC2, etc. Further, the mass ratio between LiF and the catalyst support in step S1 is 1 / 200 - 1 / 10.
[0009] Further, in step S1, the dosage of methanol is 20 - 100 ml.
[0010] Further, in step S1, the water bath heating temperature is 50 - 70 °C.
[0011] Further, in step S2, the concentration of the chloroplatinic acid aqueous solution is 0.03 - 0.05 mol / L.
[0012] Further, in step S2, the mass ratio between platinum and the catalyst support containing LiF is 1 / 200 - 1 / 10. The stirring time is 8 h - 24 h.
[0013] Further, in step S3, the reduction time is 2 - 4 h, the vacuum drying time is 8 - 24 h, and the drying temperature is 40 - 80 °C.
[0014] The selected catalyst is applied to hydrogen isotope catalytic exchange.
[0015] Further, the temperature for the catalyst to be applied to hydrogen isotope liquid-phase catalytic exchange is 40 - 400 °C, the hydrogen gas flow rate is 5 - 20 ml / min, and the concentration of HDO is about 4%.
[0016] Advantages and beneficial effects of the present invention: The present invention prepares a catalyst with a high hydrogen adsorption amount, thereby enhancing the mass transfer process of hydrogen from the gas phase main body to the catalyst surface, so that a very high catalytic exchange efficiency can be achieved at low temperatures or high hydrogen gas flow rates.
[0017] The method for preparing the catalyst in the present invention is very simple, and the catalyst support is prepared only by simple physical mixing, which is conducive to large-scale application. Description of the drawings
[0018] Figure 1 It is the XRD pattern of the catalyst prepared in Examples 1-5 of the present invention; Figure 2 It is the TEM pattern of the catalyst prepared in Example 3 of the present invention; Figure 3 It is the catalytic exchange efficiency pattern of the catalysts prepared in Examples 1-5 of the present invention at 40-80 °C with a hydrogen flow rate of 5 ml / min; Figure 4 It is the hydrogen adsorption amount pattern of the catalyst and gas carrier prepared in Example 3 of the present invention at 40 °C; Figure 5 It is the catalytic exchange efficiency pattern of the catalysts prepared in Examples 1-5 of the present invention at 80 °C with a hydrogen flow rate of 5-20 ml / min; Figure 6 It is the stability pattern of the catalysts prepared in Examples 1-5 of the present invention at 40 °C with a hydrogen flow rate of 5 ml / min; Figure 7 It is the catalytic performance pattern of the catalysts prepared in Examples 6-7 of the present invention. Embodiment
[0019] In order to make the objectives, technical solutions and advantages of the present invention more clear and definite, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0020] The following describes the specific implementation of the present invention in detail with reference to specific embodiments.
[0021] A method for preparing a hydrogen isotope catalytic exchange hydrogenophilic catalyst provided by an embodiment of the present invention includes the following steps: S1: Disperse a certain proportion of catalyst carrier and LiF into a certain amount of methanol, heat and stir in a water bath until the methanol completely volatilizes to obtain a LiF-doped catalyst carrier; S2: Disperse the LiF-doped catalyst carrier into water, then add a certain amount of chloroplatinic acid aqueous solution, and stir to obtain a uniformly dispersed aqueous solution; S3: Place the uniformly dispersed aqueous solution under a mercury lamp for reduction for a period of time, then filter by suction and dry in vacuum to obtain a catalyst solid powder.
[0022] As a preferred embodiment of the present invention, the carrier of the catalyst in step S1 is carbon, alumina or Ti3AlC2, etc. As a preferred embodiment of the present invention, the mass ratio between LiF and the catalyst carrier in step S1 is 1 / 200 - 1 / 10.
[0023] As a preferred embodiment of the present invention, in the step S1, the dosage of methanol is 20 - 100 ml.
[0024] As a preferred embodiment of the present invention, in the step S1, the water bath heating temperature is 50 - 70 °C.
[0025] As a preferred embodiment of the present invention, in the step S2, the concentration of the chloroplatinic acid aqueous solution is 0.03 - 0.05 mol / L.
[0026] As a preferred embodiment of the present invention, in the step S2, the mass ratio of platinum to the catalyst support containing LiF is 1 / 200 - 1 / 10. The stirring time is 8 h - 24 h.
[0027] As a preferred embodiment of the present invention, in the step S3, the reduction time is 2 - 4 h, the vacuum drying time is 8 - 24 h, and the drying temperature is 40 - 80 °C.
[0028] The selected catalyst is applied to hydrogen isotope catalytic exchange.
[0029] As a preferred embodiment of the present invention, the temperature for the catalyst to be applied to hydrogen isotope liquid-phase catalytic exchange is 40 - 400 °C, the hydrogen gas flow rate is 5 - 20 ml / min, and the concentration of HDO is about 4%.
[0030] Example 1: Preparation of Pt - 0.5%LiF / Ti3AlC2 catalyst Disperse 100 mg of Ti3AlC2 and 0.5 mg of LiF in 40 ml of methanol, and stir at 70 °C in a water bath until the methanol completely volatilizes to obtain a LiF-doped catalyst support; Disperse 100 mg of the LiF-doped catalyst support in water, then add 0.513 ml of 0.03 mol / L chloroplatinic acid aqueous solution, and stir for 12 h to obtain a uniformly dispersed aqueous solution; Place the uniformly dispersed aqueous solution under a mercury lamp for reduction for 2 h, then filter by suction, and vacuum dry at 60 °C for 12 h to obtain the catalyst solid powder.
[0031] Example 2: Preparation of Pt - 1%LiF / Ti3AlC2 catalyst Disperse 100 mg of Ti3AlC2 and 1 mg of LiF in 40 ml of methanol, and stir at 70 °C in a water bath until the methanol completely volatilizes to obtain a LiF-doped catalyst support; Disperse 100 mg of the LiF-doped catalyst support in water, then add 0.513 ml of 0.03 mol / L chloroplatinic acid aqueous solution, and stir for 12 h to obtain a uniformly dispersed aqueous solution; The uniformly dispersed aqueous solution was placed under a mercury lamp for reduction for 2 h, then filtered by suction, and vacuum dried at 60 °C for 12 h to obtain the catalyst solid powder.
[0032] Example 3: Preparation of Pt-5%LiF / Ti3AlC2 catalyst 100 mg of Ti3AlC2 and 5 mg of LiF were dispersed in 40 ml of methanol, and the mixture was heated and stirred in a water bath at 70 °C until the methanol completely evaporated to obtain a LiF-doped catalyst support. 100 mg of the LiF-doped catalyst support was dispersed in water, and then 0.513 ml of 0.03 mol / L chloroplatinic acid aqueous solution was added, and the mixture was stirred for 12 h to obtain a uniformly dispersed aqueous solution. The uniformly dispersed aqueous solution was placed under a mercury lamp for reduction for 2 h, then filtered by suction, and vacuum dried at 60 °C for 12 h to obtain the catalyst solid powder.
[0033] Example 4: Preparation of Pt-10%LiF / Ti3AlC2 catalyst 100 mg of Ti3AlC2 and 10 mg of LiF were dispersed in 40 ml of methanol, and the mixture was heated and stirred in a water bath at 70 °C until the methanol completely evaporated to obtain a LiF-doped catalyst support. 100 mg of the LiF-doped catalyst support was dispersed in water, and then 0.513 ml of 0.03 mol / L chloroplatinic acid aqueous solution was added, and the mixture was stirred for 12 h to obtain a uniformly dispersed aqueous solution. The uniformly dispersed aqueous solution was placed under a mercury lamp for reduction for 2 h, then filtered by suction, and vacuum dried at 60 °C for 12 h to obtain the catalyst solid powder.
[0034] Example 5: Preparation of Pt-0-LiF / Ti3AlC2 catalyst 100 mg of Ti3AlC2 was dispersed in 40 ml of methanol, and the mixture was heated and stirred in a water bath at 70 °C until the methanol completely evaporated to obtain a LiF-doped catalyst support. 100 mg of the catalyst support was dispersed in water, and then 0.513 ml of 0.03 mol / L chloroplatinic acid aqueous solution was added, and the mixture was stirred for 12 h to obtain a uniformly dispersed aqueous solution. The uniformly dispersed aqueous solution was placed under a mercury lamp for reduction for 2 h, then filtered by suction, and vacuum dried at 60 °C for 12 h to obtain the catalyst solid powder.
[0035] First, the supports and catalysts involved in Examples 1-5 were characterized. Figure 1 The XRD results were given. It can be seen that the addition of LiF significantly increased the diffraction peak at 45°, which was attributed to the (200) crystal plane of LiF.
[0036] Figure 2The TEM image and dark field image of Example 3 are given. It can be seen from them that platinum does not show obvious agglomeration and is relatively evenly distributed.
[0037] Compared with Examples 1-5, the difference lies in the amount of LiF used in each example.
[0038] The exchange performance tests were carried out on Examples 1-5. The tests were carried out in a semi-batch reactor. 60 mg of catalyst powder was taken and evenly coated on the reactor wall through polydimethylsiloxane. 5 g of an HDO aqueous solution with a molar concentration of about 4% was added to the reactor. The hydrogen flow rate was set at 5-20 ml / min, and the temperature was controlled at 40-80 °C. And the catalytic exchange efficiency was used to evaluate the catalyst. Catalytic exchange efficiency = (HD concentration at the reactor outlet - HD concentration at the reactor inlet) / (equilibrium HD concentration at the reactor outlet - HD concentration at the reactor inlet).
[0039] Figure 3 It shows the influence of temperature on the reaction. At 40 °C, the catalytic exchange efficiency of the catalyst prepared in Example 3 can reach 92%, which is far higher than previous studies. Achieving a high catalytic exchange efficiency at low temperatures is beneficial for reducing energy consumption.
[0040] Figure 4 It shows that the addition of LiF greatly improves the hydrogen adsorption capacity of the catalyst.
[0041] Figure 5 It shows the influence of hydrogen flow rate on the reaction. It can be seen that as the gas velocity increases, the catalytic exchange efficiency of the catalyst prepared in Example 3 decreases very little. At low flow rates, the catalytic exchange efficiency of the catalyst prepared in Example 2 is higher than that of the catalyst prepared in Example 4. As the hydrogen flow rate increases, the catalytic exchange efficiency of the catalyst prepared in Example 4 gradually exceeds that of the catalyst prepared in Example 4. This also shows that at high hydrogen flow rates, the hydrogen adsorption capacity of the catalyst is a very crucial factor. Improving the hydrogen adsorption capacity of the catalyst is beneficial for large-scale applications.
[0042] Figure 6 It shows the stability of the catalysts of Examples 1-5. Within 10 hours, the catalysts did not show deactivation. On the one hand, this is because polydimethylsiloxane provides a hydrophobic environment, and on the other hand, it benefits from the fact that this carrier is a non-porous material, eliminating the influence of internal diffusion and capillary condensation of water on the catalyst.
[0043] Example 6: 100 mg of carbon and 1 mg of LiF were dispersed in 40 ml of methanol, and stirred in a 70 °C water bath until the methanol completely evaporated to obtain a LiF-doped catalyst support; Disperse 100 mg of the LiF-doped catalyst support in water, then add 0.513 ml of an aqueous solution of chloroplatinic acid with a concentration of 0.03 mol / L, and stir for 12 h to obtain a uniformly dispersed aqueous solution; Place the uniformly dispersed aqueous solution under a mercury lamp for reduction for 2 h, then perform suction filtration, and dry in vacuum at 60 °C for 12 h to obtain the catalyst solid powder.
[0044] Example 7: Disperse 100 mg of alumina and 1 mg of LiF in 40 ml of methanol, heat and stir in a water bath at 70 °C until the methanol completely evaporates to obtain the LiF-doped catalyst support; Disperse 100 mg of the LiF-doped catalyst support in water, then add 0.513 ml of an aqueous solution of chloroplatinic acid with a concentration of 0.03 mol / L, and stir for 12 h to obtain a uniformly dispersed aqueous solution; Place the uniformly dispersed aqueous solution under a mercury lamp for reduction for 2 h, then perform suction filtration, and dry in vacuum at 60 °C for 12 h to obtain the catalyst solid powder.
[0045] From Figure 7 It can be seen that the change trend of the catalytic exchange efficiency in Examples 6-7 conforms to the conclusion we obtained above, and at the same time, the general applicability of our invention can be determined.
[0046] The above is only the preferred embodiment of the present invention. It should be noted that for those skilled in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent.
Claims
1. A preparation method of a hydrogen isotope catalytic exchange hydrogenophilic catalyst, characterized in that, It includes the following steps: S1: Disperse a certain amount of LiF and catalyst support into methanol, stir until the methanol completely evaporates to obtain solid powder; S2: Disperse the solid powder obtained in S1 into water, add an appropriate amount of chloroplatinic acid aqueous solution and stir to obtain a suspension; S3: Stir and reduce the suspension obtained in S2 under a mercury lamp, filter by suction, and vacuum dry to obtain the hydrogen isotope liquid-phase catalytic exchange catalyst.
2. The preparation method of a hydrogen isotope catalytic exchange hydrogenophilic catalyst according to claim 1, characterized in that, The support of the catalyst is various conventional catalyst supports such as carbon, alumina, or Ti3AlC2.
3. The preparation method of a hydrogen isotope catalytic exchange hydrogenophilic catalyst according to claim 1, characterized in that, The mass ratio of LiF to the support is 1 / 200 - 1 / 10.
4. The preparation method of a hydrogen isotope catalytic exchange hydrogenophilic catalyst according to claim 1, characterized in that, The amount of methanol is 20 - 100 ml.
5. The preparation method of a hydrogen isotope catalytic exchange hydrogenophilic catalyst according to claim 1, characterized in that, The mass percentage of the support in the catalyst is 90% - 99%, and the mass ratio of platinum in the catalyst is 1% - 10%.
6. The liquid-phase catalytic exchange catalyst for hydrogen isotopes according to claim 1, wherein The reduction time of the mercury lamp is 2 - 3 h, the vacuum drying temperature is 60 - 80 °C, and the vacuum drying time is 10 - 24 h.
7. A hydrogen isotope liquid-phase catalytic exchange catalyst prepared by the preparation method of the hydrogen isotope catalytic exchange catalyst according to any one of claims 1.
8. An application of the hydrogen isotope catalytic exchange catalyst according to claim 7 in catalytic exchange.
9. The application according to claim 8, wherein By introducing lithium fluoride into the catalyst, the hydrogen adsorption capacity of the catalyst is increased, thereby enhancing the mass transfer process and solving the problems such as too low efficiency of the hydrogen isotope catalytic exchange reaction at low temperatures.