A catalytic electrode for electrocatalytic preparation of aliphatic compounds from aromatic compounds and its use
By designing a composite structure of a conductive substrate, a carbide support layer, and a metal nanoparticle layer on an electrocatalytic electrode, the problems of insufficient catalytic activity and poor selectivity in existing electrocatalytic technologies are solved, achieving efficient conversion and highly selective generation of aromatic compounds into alicyclic compounds. This technology is applicable to the fields of fine chemicals, pharmaceuticals, and polymer monomer synthesis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI INSTITUTE OF APPLIED PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2026-03-12
- Publication Date
- 2026-06-05
AI Technical Summary
Existing electrocatalytic technologies have insufficient catalytic activity and poor selectivity in the hydrogenation of aromatic compounds to alicyclic compounds. Furthermore, the lack of dedicated electrode design leads to numerous side reactions and low Faraday efficiency, which cannot meet the needs of continuous industrial production.
A catalytic electrode is constructed by sequentially placing a support layer and a layer of metal nanoparticles on a conductive substrate. The support layer is one or more of Cr3C2, WC, W2C, and MoC, and the metal is one or more of Pt, Pd, Au, Ag, and Cu. Through the synergistic effect of carbides and metals, highly selective adsorption of aromatic compounds and rapid desorption of alicyclic products are achieved.
It achieves efficient conversion of aromatic compounds to alicyclic compounds at room temperature and pressure, with a conversion rate exceeding 95%, selectivity exceeding 96%, and current efficiency exceeding 34%. It effectively suppresses side reactions, possesses excellent chemical and mechanical stability, and is suitable for industrial production.
Abstract
Description
Technical Field
[0001] This invention relates to the fields of electrochemical catalysis and organic synthesis, and more specifically to a catalytic electrode for the electrocatalytic preparation of alicyclic compounds from aromatic compounds and its application. Background Technology
[0002] The hydrogenation saturation reaction of aromatic compounds, which transforms structurally stable benzene ring aromatic systems into alicyclic structures through hydrogenation, is a core and crucial step in the fields of fine chemicals, pharmaceuticals, and polymer monomer synthesis. Alicyclic derivatives such as cyclohexene, cyclohexanol, and cyclohexanecarboxylic acid are important intermediates in the production of nylon, plasticizers, fragrances, and pharmaceuticals.
[0003] Currently, the conversion of aromatic compounds to alicyclic compounds in industry and laboratories mainly relies on traditional thermocatalytic hydrogenation technology, which is mainly divided into two routes: heterogeneous catalytic hydrogenation and homogeneous catalytic hydrogenation. Heterogeneous catalytic hydrogenation requires harsh conditions of high temperature (usually >100℃) and high pressure hydrogen gas (usually >1MPa). The supported noble metal catalysts (such as Pt, Pd, Ru) or non-noble metal catalysts (such as Ni) used have insufficient stability, which can easily lead to side reactions such as over-hydrogenation and hydrogenolysis of the target product, significantly reducing product selectivity. Although homogeneous catalytic hydrogenation uses soluble metal complex catalysts and has certain catalytic activity and selectivity, it suffers from drawbacks such as difficulty in separating the catalyst from the product, high preparation and use costs, and the tendency for metal residues to affect product purity.
[0004] Overall, although traditional thermocatalytic hydrogenation technology is relatively mature, it generally has significant shortcomings: On the one hand, the high temperature and high pressure reaction conditions place stringent requirements on the pressure and temperature resistance of the production equipment, which not only increases the investment and maintenance costs of the equipment, but also results in huge energy losses. At the same time, the large-scale storage and use of high-pressure hydrogen poses serious safety hazards. On the other hand, both types of catalysts have their own performance defects, and side reactions are difficult to control, which further limits the production efficiency and product quality of this technology.
[0005] In recent years, electrocatalytic synthesis, as a green and sustainable new strategy for organic synthesis, has received widespread attention and in-depth research in the industry. This technology uses clean electrical energy as the reaction driving force and electrons as a "clean" reducing agent, enabling chemical reactions to occur under mild conditions of ambient temperature and pressure. This fundamentally avoids the use of high-pressure hydrogen and offers significant advantages such as safe operation, low energy consumption, mild reaction conditions, and easy and precise process control. Applying electrocatalysis to the hydrogenation of aromatic rings to prepare alicyclic compounds is considered a highly promising technological route to replace traditional thermocatalytic hydrogenation technology and has become a research hotspot in this field.
[0006] However, current electrocatalysis technology still faces several key technical bottlenecks in the practical application of hydrogenation of aromatic compounds to alicyclic compounds: First, the catalytic activity of existing electrodes is insufficient, failing to efficiently achieve the saturated hydrogenation conversion of aromatic rings; second, the electrodes exhibit poor selectivity for target products, making it difficult to effectively suppress side reactions such as hydrogen evolution, resulting in low Faraday efficiency and limited raw material utilization and product purity; third, the electrode structure design lacks specificity, failing to incorporate the characteristics of aromatic ring hydrogenation reactions for targeted development, resulting in an unreasonable number and distribution of active sites, and failing to achieve synergistic optimization of the adsorption capacity for aromatic ring substrates, the stabilization capacity for reaction intermediates, and the desorption capacity for alicyclic products. Currently, most related studies utilize commercial electrodes or simply modified general-purpose electrodes, lacking dedicated catalytic electrodes specifically designed for aromatic ring hydrogenation reactions. How to construct catalytic electrodes with high conductivity, abundant and stable active sites, and suitable adsorption / desorption capabilities for aromatic ring substrates and intermediates has become a core technical problem urgently needing to be solved in this field.
[0007] In summary, there is an urgent need in this field to develop a novel dedicated electrocatalytic electrode that can efficiently catalyze the hydrogenation reaction of aromatic compounds under mild electrochemical conditions (room temperature and pressure, low overpotential), while effectively suppressing side reactions such as hydrogen evolution, achieving high Faradaic efficiency and high selectivity in the formation of target alicyclic compounds, and possessing excellent chemical and mechanical stability to meet the practical needs of continuous industrial production. Summary of the Invention
[0008] To address the technical problems of harsh reaction conditions, numerous side reactions, and lack of specific design, low activity, and low selectivity of electrocatalytic electrodes in existing thermocatalytic hydrogenation technologies, this invention aims to provide a catalytic electrode for the electrocatalytic preparation of alicyclic compounds from aromatic compounds and its application.
[0009] The catalytic electrode for the electrocatalytic preparation of alicyclic compounds from aromatic compounds according to the present invention comprises a conductive substrate and a support layer and a loaded metal nanoparticle layer sequentially disposed on the surface of the conductive substrate. The support layer is one or more carbides selected from Cr3C2, WC, W2C, MoC, and Mo2C, and the metal of the loaded metal nanoparticle layer is one or more selected from Pt, Pd, Au, Ag, and Cu.
[0010] In a preferred embodiment, the catalytic electrode is one or more of Ag / MoC, Au / WC, Cu / W2C, Pt / Cr3C2, and Pd / Mo2C composite materials.
[0011] In a preferred embodiment, the thickness of the carrier layer is 0.1-2 μm.
[0012] In a preferred embodiment, the size of the metal nanoparticles is 2-5 nm.
[0013] In a preferred embodiment, the load metal content is 0.5wt%-20wt%.
[0014] In a preferred embodiment, the contact angle between the catalytic electrode and benzene is 1-20°, and the contact angle between the catalytic electrode and cyclohexane is 80-150°.
[0015] According to the present invention, the catalytic electrode described above is used in the electrocatalytic preparation of alicyclic compounds from aromatic compounds, wherein the catalytic electrode is a cathode, and the aromatic compound is one or more of benzoic acid, terephthalic acid, phthalic acid, and methyl / ethyl / trifluoromethyl substituted benzoic acid.
[0016] In a preferred embodiment, the substituted benzoic acid is one or more of 2-methylbenzoic acid, 3-methylbenzoic acid, 2-ethylbenzoic acid, 2-(trifluoromethyl)benzoic acid, and 3-(trifluoromethyl)benzoic acid.
[0017] In a preferred embodiment, the operating temperature range of the catalytic electrode is 0-120°C.
[0018] In a preferred embodiment, the conversion rate of aromatic compounds exceeds 95%, the selectivity of the prepared alicyclic compounds exceeds 96%, and the current efficiency exceeds 34%.
[0019] The catalytic electrode of this invention employs a hierarchical structure design consisting of a conductive substrate, a carbide support layer, and a noble metal / non-noble metal nanoparticle layer. Relying on the synergistic effect of the carbide support and the supported metal, it utilizes the strong water dissociation capacity of the carbide to provide a sufficient hydrogen source for the hydrogenation reaction, while simultaneously leveraging the π-complexation ability of the metal to achieve highly selective adsorption of aromatic compounds and rapid desorption of alicyclic products. This effectively solves the technical problems of existing technologies, such as harsh conditions, high equipment requirements, significant safety hazards, insufficient catalyst stability, numerous side reactions, low activity, poor selectivity, and lack of specific structural design in electrocatalytic hydrogenation reactions. It can efficiently electrocatalyze the conversion of aromatic compounds to alicyclic compounds under mild conditions, significantly improving the conversion rate of aromatic compounds and the selectivity of target alicyclic compounds, effectively suppressing side reactions such as hydrogen evolution, reducing reaction energy consumption, and providing a stable electrode structure. The preparation process is simple, diverse, and low-cost, meeting the needs of continuous industrial production and showing broad application prospects in the fields of electrochemical catalysis and organic synthesis. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0021] This invention provides a catalytic electrode for the electrocatalytic preparation of alicyclic compounds from aromatic compounds. The electrode comprises a conductive substrate and a support layer and a layer of supported metal nanoparticles sequentially disposed on the surface of the conductive substrate. The support layer is one or more carbides selected from Cr3C2, WC, W2C, MoC, and Mo2C. The metal in the supported metal nanoparticle layer is one or more selected from Pt, Pd, Au, Ag, and Cu. In a preferred embodiment, the catalytic electrode is one or more composite materials selected from Ag / MoC, Au / WC, Cu / W2C, Pt / Cr3C2, and Pd / Mo2C. In a preferred embodiment, the conductive substrate is any one of graphite, nickel sheet, nickel foam, copper sheet, copper foam, low-carbon steel, or stainless steel, possessing advantages such as good conductivity, excellent mechanical properties, good ductility, and low cost. In a preferred embodiment, the thickness of the support layer is 0.1-2 μm. In a preferred embodiment, the thickness of the support layer is 0.8-1.5 μm. In a preferred embodiment, the thickness of the support layer is 1-1.4 μm. In preferred embodiments, the metal nanoparticle size is 2-5 nm. In preferred embodiments, the metal nanoparticle size is 2.6-4.5 nm. In preferred embodiments, the metal nanoparticle size is 3.5-3.8 nm. In one preferred embodiment, the metal nanoparticle size is 3 nm. In preferred embodiments, the metal loading is 0.5 wt%-20 wt%. In preferred embodiments, the metal loading is 1.6 wt%-8.4 wt%. In preferred embodiments, the metal loading is 2.1 wt%-7 wt%. In one preferred embodiment, the metal loading is 5.6 wt%. In preferred embodiments, the contact angle between the catalytic electrode and benzene is 1-20°, and the contact angle with cyclohexane is 80-150°. In preferred embodiments, the contact angle between the catalytic electrode and benzene is 8-16°, and the contact angle with cyclohexane is 83-101°. In preferred embodiments, the contact angle between the catalytic electrode and benzene is 9-14°, and the contact angle with cyclohexane is 86-96°. In a preferred embodiment, the catalytic electrode has a contact angle of 11° with benzene and a contact angle of 92° with cyclohexane.
[0022] This invention also provides the application of the above-described catalytic electrode in the electrocatalytic preparation of alicyclic compounds from aromatic compounds, wherein the catalytic electrode is a cathode, and the aromatic compound is one or more of benzoic acid, terephthalic acid, phthalic acid, and methyl / ethyl / trifluoromethyl substituted benzoic acid. In a preferred embodiment, the substituted benzoic acid is one or more of 2-methylbenzoic acid, 3-methylbenzoic acid, 2-ethylbenzoic acid, 2-(trifluoromethyl)benzoic acid, and 3-(trifluoromethyl)benzoic acid. In a preferred embodiment, the alicyclic compound is one or more of cyclohexanecarboxylic acid, cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2-methylcyclohexanecarboxylic acid, 3-methylcyclohexanecarboxylic acid, 2-ethylcyclohexanecarboxylic acid, 2-(trifluoromethyl)cyclohexanecarboxylic acid, and 3-(trifluoromethyl)cyclohexanecarboxylic acid. In a preferred embodiment, the operating temperature range of the catalytic electrode is 0-120°C. In a preferred embodiment, the operating temperature range of the catalytic electrode is 0-90°C. In a preferred embodiment, the operating temperature range of the catalytic electrode is 0-80°C. In a preferred embodiment, the temperature is 45°C. In a preferred embodiment, the electrocatalytic reaction system comprises: an aromatic compound dissolved in 0.5M KOH solution as the cathode electrolyte, a 0.5M KOH aqueous solution as the anode electrolyte, and an anion exchange membrane separating the anode and cathode chambers. In a preferred embodiment, nickel foam is used as the anode. In a preferred embodiment, the electrolysis current density is 5-20 mA / cm². 2 In a preferred embodiment, the electrolysis current density is 8-15 mA / cm². 2 In a preferred embodiment, the electrolysis current density is 11 mA / cm². 2 In preferred embodiments, the conversion rate of aromatic compounds exceeds 95%. In preferred embodiments, the selectivity of alicyclic compounds exceeds 96%. In preferred embodiments, the current efficiency exceeds 34%. In preferred embodiments, the conversion rate of aromatic compounds is 95.3%-98.6%, the selectivity of the prepared alicyclic compounds is 96.5%-98.5%, and the current efficiency is 34.5%-42%. In preferred embodiments, the conversion rate of aromatic compounds is 95.8%-98.2%, the selectivity of the prepared alicyclic compounds is 96.7%-98.4%, and the current efficiency is 35.6%-41.5%. In one preferred embodiment, the conversion rate of aromatic compounds is 98.1%, the selectivity of the prepared alicyclic compounds is 98.2%, and the current efficiency is 40.4%. In preferred embodiments, when electrocatalyzing benzoic acid to prepare cyclohexanecarboxylic acid, terephthalic acid to prepare cyclohexanedicarboxylic acid, and phthalic acid to prepare 1,2-cyclohexanedicarboxylic acid, the conversion rate of aromatic compounds exceeds 98%, the selectivity of the prepared alicyclic compounds exceeds 98%, and the current efficiency exceeds 40%.
[0023] Example 1
[0024] A MoC layer was prepared on the surface of nickel foam using thermal spraying as a catalytic electrode support. Subsequently, nano-Ag particles were prepared on the MoC layer surface by electrochemical deposition to obtain an Ag / MoC catalytic electrode on a nickel foam substrate. The MoC layer was 1 μm thick, the Ag particles were approximately 3 nm in size, and the Ag loading was approximately 7 wt%. The contact angle between this Ag / MoC catalytic electrode and benzene was 11°, and the contact angle with cyclohexane was 92°.
[0025] 0.1 g of terephthalic acid was dissolved in 100 mL of 0.5 M KOH solution as the cathode electrolyte, and 0.5 M KOH aqueous solution was used as the anode electrolyte. An anion exchange membrane was used to separate the anode and cathode chambers. An Ag / MoC catalytic electrode was used as the cathode, and nickel foam was used as the anode to construct an electrolytic device. The electrolysis was performed at 45 °C and 5 mA / cm². 2 Electrolysis was carried out continuously for 12 hours at the specified current density. After the electrolysis reaction was completed, a solution containing cyclohexanedicarboxylic acid was obtained in the cathode electrolysis chamber. 100 mL of 0.5 M H₂SO₄ was added to the solution, and the solid precipitated in the liquid was removed to obtain cyclohexanedicarboxylic acid. The calculated conversion rates were: terephthalic acid 98.2%, cyclohexanedicarboxylic acid selectivity 98.5%, and current efficiency 42%.
[0026] Example 2
[0027] A WC layer was prepared on the surface of copper foam as a catalytic electrode support using molten salt electrodeposition. Subsequently, nano-Au particles were prepared on the WC layer surface by impregnation, resulting in an Au / WC catalytic electrode on a copper foam substrate. The WC layer was 1.5 μm thick, the supported Au particles were approximately 2.6 nm in size, and the Au loading was approximately 5.6 wt%. The contact angle between this Au / WC catalytic electrode and benzene was 16°, and the contact angle with cyclohexane was 96°.
[0028] 0.1 g of benzoic acid was dissolved in 100 mL of 0.5 M KOH solution as the cathode electrolyte, and 0.5 M KOH aqueous solution was used as the anode electrolyte. An anion exchange membrane was used to separate the anode and cathode chambers. An Au / WC catalytic electrode was used as the cathode, and nickel foam was used as the anode to construct an electrolytic device. The electrolysis was performed at 45 °C and 8 mA / cm². 2 Electrolysis was carried out continuously for 15 hours at the specified current density. After the electrolysis reaction was completed, a solution containing cyclohexanecarboxylic acid was obtained in the cathode electrolysis chamber. 100 mL of 0.5 M H2SO4 was added to the solution, and the solid precipitated in the liquid was removed to obtain cyclohexanecarboxylic acid. The calculated conversion rates were: benzoic acid 98.6%, cyclohexanecarboxylic acid selectivity 98.4%, and current efficiency 41.5%.
[0029] Example 3
[0030] A W2C layer was prepared on a low-carbon steel surface using physical vapor deposition (PVD) as a catalytic electrode support. Subsequently, nano-Cu particles were deposited on the W2C layer surface via electrodeposition to obtain a Cu / W2C catalytic electrode on a low-carbon steel substrate. The W2C layer was 0.8 μm thick, the supported Cu particles were approximately 4.5 nm in size, and the Cu loading was approximately 8.4 wt%. The contact angle between this Cu / W2C catalytic electrode and benzene was 8°, and the contact angle with cyclohexane was 101°.
[0031] 0.1 g of phthalic acid was dissolved in 100 mL of 0.5 M KOH solution as the cathode electrolyte, and 0.5 M KOH aqueous solution was used as the anode electrolyte. An anion exchange membrane was used to separate the anode and cathode chambers. A Cu / W₂C catalytic electrode was used as the cathode, and nickel foam was used as the anode to construct an electrolytic device. The electrolysis was performed at 45 °C and 11 mA / cm². 2 Electrolysis was carried out continuously for 13 hours at the specified current density. After the electrolysis reaction was completed, a solution containing 1,2-cyclohexanedicarboxylic acid was obtained in the cathode electrolysis chamber. 100 mL of 0.5 M H₂SO₄ was added to the solution, and the solid precipitated in the liquid was removed to obtain 1,2-cyclohexanedicarboxylic acid. The calculated phthalic acid conversion rate was 98.1%, the selectivity for 1,2-cyclohexanedicarboxylic acid was 98.2%, and the current efficiency was 40.4%.
[0032] Example 4
[0033] A Cr3C2 layer was prepared on the surface of 304 stainless steel using chemical vapor deposition as a catalytic electrode support. Subsequently, nano-Pt particles were prepared on the surface of the Cr3C2 layer using a hydrothermal method, resulting in a Pt / Cr3C2 catalytic electrode on a 304 stainless steel substrate. The Cr3C2 layer was 0.8 μm thick, the supported Pt particles were approximately 3.8 nm in size, and the Pt loading was approximately 1.6 wt%. The contact angle between this Pt / Cr3C2 catalytic electrode and benzene was 14°, and the contact angle with cyclohexane was 86°.
[0034] 0.1 g of 2-ethylbenzoic acid was dissolved in 100 mL of 0.5 M KOH solution as the cathode electrolyte, and 0.5 M KOH aqueous solution was used as the anode electrolyte. An anion exchange membrane was used to separate the anode and cathode chambers. A Pt / Cr3C2 catalytic electrode was used as the cathode, and nickel foam was used as the anode to construct an electrolytic device. The electrolysis was performed at 45 °C and 15 mA / cm². 2 Electrolysis was carried out continuously for 15 hours at the specified current density. After the electrolysis reaction was completed, a solution containing 2-ethylcyclohexanecarboxylic acid was obtained in the cathode electrolysis chamber. 100 mL of 0.5 M H₂SO₄ was added to the solution, and the solid precipitated in the liquid was removed to obtain 2-ethylcyclohexanecarboxylic acid. The calculated conversion rate of 2-ethylbenzoic acid was 95.3%, the selectivity of 2-ethylcyclohexanecarboxylic acid was 96.5%, and the current efficiency was 34.5%.
[0035] Example 5
[0036] A Mo2C layer was prepared on the surface of a graphite sheet using chemical vapor deposition (CVD) as a catalytic electrode support. Subsequently, nano-Pd particles were fabricated on the Mo2C layer surface via a hydrothermal method, resulting in a Pd / Mo2C catalytic electrode on a graphite sheet substrate. The Mo2C layer was 1.4 μm thick, the supported Pd particles were approximately 3.5 nm in size, and the Pd loading was approximately 2.1 wt%. This Pd / Mo2C catalytic electrode exhibited a contact angle of 9° with benzene and 83° with cyclohexane.
[0037] 0.1 g of 3-(trifluoromethyl)benzoic acid was dissolved in 100 mL of 0.5 M KOH solution as the cathode electrolyte, and 0.5 M KOH aqueous solution was used as the anode electrolyte. An anion exchange membrane was used to separate the anode and cathode chambers. A Pd / Mo₂C catalytic electrode was used as the cathode, and nickel foam was used as the anode to construct an electrolytic device. The electrolysis was performed at 45 °C and 20 mA / cm². 2 Electrolysis was carried out continuously for 15 hours at the specified current density. After the electrolysis reaction was completed, a solution containing 3-(trifluoromethyl)cyclohexanecarboxylic acid was obtained in the cathode electrolysis chamber. 100 mL of 0.5 M H₂SO₄ was added to the solution, and the solid precipitated in the liquid was removed to obtain 3-(trifluoromethyl)cyclohexanecarboxylic acid. The calculated conversion rates of 3-(trifluoromethyl)benzoic acid were 95.8%, the selectivity of 3-(trifluoromethyl)cyclohexanecarboxylic acid was 96.7%, and the current efficiency was 35.6%.
[0038] Comparative Example 1
[0039] A MoC layer was prepared on the surface of nickel foam by thermal spraying to obtain a MoC catalytic electrode without loaded metal nanoparticles. The thickness of the MoC layer in the prepared MoC catalytic electrode was 1 μm. The contact angle between the MoC catalytic electrode and benzene was 66° and the contact angle with cyclohexane was 71°.
[0040] 0.1 g of terephthalic acid was dissolved in 100 mL of 0.5 M KOH solution as the cathode electrolyte, and 0.5 M KOH aqueous solution was used as the anode electrolyte. An anion exchange membrane was used to separate the anode and cathode chambers. A MoC catalytic electrode was used as the cathode, and nickel foam was used as the anode to construct an electrolytic device. The electrolysis was performed at 45 °C and 5 mA / cm². 2 Electrolysis was carried out continuously for 12 hours at the specified current density. After the electrolysis reaction was completed, a solution containing cyclohexanedicarboxylic acid was obtained in the cathode electrolysis chamber. 100 mL of 0.5 M H₂SO₄ was added to the solution, and the solid precipitated in the liquid was removed to obtain cyclohexanedicarboxylic acid. The calculated conversion rates were: terephthalic acid 38.2%, cyclohexanedicarboxylic acid selectivity 18.5%, and current efficiency 5.2%.
[0041] Comparative Example 2
[0042] A commercially modified Ag / C catalytic electrode was prepared by drop-coating a mixture of commercial Ag / C, binder, and dispersant onto the surface of carbon paper using nickel foam as a substrate. The electrode had a contact angle of 78° with benzene and 83° with cyclohexane.
[0043] 0.1 g of terephthalic acid was dissolved in 100 mL of 0.5 M KOH solution as the cathode electrolyte, and 0.5 M KOH aqueous solution was used as the anode electrolyte. An anion exchange membrane was used to separate the anode and cathode chambers. An Ag / C catalytic electrode was used as the cathode, and nickel foam was used as the anode to construct an electrolytic device. The electrolysis was performed at 45 °C and 5 mA / cm². 2 Electrolysis was carried out continuously for 12 hours at the specified current density. After the electrolysis reaction was completed, a solution containing cyclohexanedicarboxylic acid was obtained in the cathode electrolysis chamber. 100 mL of 0.5 M H₂SO₄ was added to the solution, and the solid precipitated in the liquid was removed to obtain cyclohexanedicarboxylic acid. The calculated conversion rates were: terephthalic acid 31.5%, cyclohexanedicarboxylic acid selectivity 13.5%, and current efficiency 2.4%.
[0044] As can be seen from the results of Examples 1-5 and Comparative Examples 1-2 above, the catalytic electrode of the present invention, through the three-layer composite structure design of "conductive substrate-carbide support layer-metal nanoparticle layer", achieves highly efficient catalysis for the hydrogenation of aromatic compounds to prepare alicyclic compounds. The feed conversion rate exceeds 95% and the product selectivity exceeds 96%, which is far superior to pure carbide electrodes without metal nanoparticles and commercially modified electrodes. In particular, for the catalytic reactions of benzoic acid, terephthalic acid, and phthalic acid, the feed conversion rate exceeds 98%, the product selectivity exceeds 98%, and the current efficiency exceeds 40%. At the same time, it effectively suppresses side reactions such as hydrogen evolution, demonstrating excellent catalytic performance.
[0045] This invention utilizes the strong water dissociation ability of carbides to generate a large amount of H*, while simultaneously leveraging the strong hydrogenation ability of the supported metal to promote the electrocatalytic hydrogenation reaction. When metal nanoparticles with π-complexing ability are loaded onto carbides, a strong interaction occurs between the carbides and the metal, effectively stabilizing these metal nanoparticles. This allows the composite material of the catalytic electrode to maintain a high selective adsorption capacity for aromatic ring compounds containing delocalized large π bonds for a long period, thereby promoting the electrocatalytic hydrogenation reaction of aromatic compounds. At the same time, the interaction with alicyclic compounds without delocalized π bonds is weak, thus enabling the rapid desorption of alicyclic compounds from the electrocatalytic product. That is, it is both benzene-friendly and cyclohexane-repellent, ensuring the efficient and continuous catalytic reaction.
[0046] The catalytic electrode of this invention can efficiently catalyze the hydrogenation reaction of aromatic compounds under mild electrochemical conditions (0-120℃) and effectively suppress side reactions, especially the hydrogen evolution reaction. It features low energy consumption, high efficiency, and good selectivity, achieving high Faradaic efficiency and highly selective product formation, and possesses excellent chemical and mechanical stability. Compared with existing technologies, the catalytic electrode of this invention has strong water dissociation ability and efficient π-complexation ability, realizing the efficient electrocatalytic preparation of alicyclic compounds from aromatic compounds under ambient temperature and pressure conditions. Furthermore, the preparation methods of the catalytic electrode are simple and diverse, including electroplating, electroless plating, molten salt electrochemistry, hydrothermal treatment, impregnation, physical vapor deposition, and chemical vapor deposition, with low preparation costs. Therefore, the catalytic electrode of this invention has broad industrial application prospects in fine chemicals, pharmaceuticals, and polymer monomer synthesis.
[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.
Claims
1. A catalytic electrode for the electrocatalytic preparation of alicyclic compounds from aromatic compounds, characterized in that, The catalytic electrode includes a conductive substrate and a support layer and a layer of loaded metal nanoparticles sequentially disposed on the surface of the conductive substrate. The support layer is one or more carbides selected from Cr3C2, WC, W2C, MoC, and Mo2C, and the metal of the layer of loaded metal nanoparticles is one or more selected from Pt, Pd, Au, Ag, and Cu.
2. The catalytic electrode according to claim 1, characterized in that, The catalytic electrode is one or more of Ag / MoC, Au / WC, Cu / W2C, Pt / Cr3C2, and Pd / Mo2C composite materials.
3. The catalytic electrode according to claim 1, characterized in that, The thickness of the carrier layer is 0.1-2 μm.
4. The catalytic electrode according to claim 1, characterized in that, The size of the metal nanoparticles is 2-5 nm.
5. The catalytic electrode according to claim 1, characterized in that, The load metal content is 0.5wt%-20wt%.
6. The catalytic electrode according to claim 1, characterized in that, The contact angle between the catalytic electrode and benzene is 1-20°, and the contact angle between it and cyclohexane is 80-150°.
7. The application of the catalytic electrode according to any one of claims 1-6 in the electrocatalytic preparation of alicyclic compounds from aromatic compounds, characterized in that, The catalytic electrode is a cathode, and the aromatic compound is one or more of benzoic acid, terephthalic acid, phthalic acid, and methyl / ethyl / trifluoromethyl substituted benzoic acid.
8. The application according to claim 7, characterized in that, The substituted benzoic acid is one or more of 2-methylbenzoic acid, 3-methylbenzoic acid, 2-ethylbenzoic acid, 2-(trifluoromethyl)benzoic acid, and 3-(trifluoromethyl)benzoic acid.
9. The application according to claim 7, characterized in that, The operating temperature range of the catalytic electrode is 0-120℃.
10. The application according to claim 7, characterized in that, The conversion rate of aromatic compounds exceeds 95%, the selectivity of prepared alicyclic compounds exceeds 96%, and the current efficiency exceeds 34%.