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CN-122013224-A - Crown ether substituted nickel phthalocyanine catalyst and compound thereof, preparation method and application thereof in electrocatalytic reduction of carbon dioxide

CN122013224ACN 122013224 ACN122013224 ACN 122013224ACN-122013224-A

Abstract

The invention discloses a crown ether substituted nickel phthalocyanine catalyst, a compound thereof, a preparation method and application thereof in electrocatalytic reduction of carbon dioxide. The catalyst is synthesized by taking 4, 5-dicyanobenzo-18-crown-6 ether and nickel salt as raw materials under specific conditions, and a hybrid catalyst is formed by loading the catalyst on the surface of a carbon nano tube. The invention also discloses application of the catalyst in an acidic Membrane Electrode (MEA) electrolytic cell based on a bipolar membrane (BPM), the electrolytic cell can realize high-efficiency electrocatalytic CO 2 reduction reaction in a wide CO 2 feeding concentration range (CO 2 volume concentration is 10-100%), the selectivity of carbon monoxide is high, and when the CO 2 volume concentration is as low as 10%, the CO selectivity can still reach 77.77%, and no liquid by-product is generated. The invention solves the problems of complex product, unidentified performance under acidic condition and poor adaptability of low-concentration CO 2 in the prior art, and can be widely applied to the fields of capturing and converting low-concentration CO 2 , energy storage systems, extreme environmental carbon management and the like.

Inventors

  • ZHU LEI
  • LI JIAN
  • LIU SHUO

Assignees

  • 杭州市拱墅区工大未来技术研究院

Dates

Publication Date
20260512
Application Date
20260409

Claims (10)

  1. 1. The preparation method of the crown ether substituted nickel phthalocyanine catalyst compound is characterized by comprising the following process steps: s1, synthesizing crown ether substituted nickel phthalocyanine molecular catalyst: s11, mixing 4, 5-dicyanobenzo-18-crown-6 ether with nickel salt in an organic solvent; s12, reacting for 20-28 hours at the temperature of 130-160 ℃ under the protection of inert atmosphere; S13, after the reaction is finished, separating and purifying to obtain the crown ether substituted nickel phthalocyanine molecular catalyst; S2, anchoring of the molecular catalyst: s21, dissolving the crown ether substituted nickel phthalocyanine molecular catalyst and alkali metal salt obtained in the step S1 in a first solvent to form a catalyst precursor solution; s22, mixing a second solvent with carbon nano tubes dispersed therein with the catalyst precursor solution, and carrying out ultrasonic treatment to load a molecular catalyst on the surface of the conductive carrier; S23, separating, washing and drying to obtain a closely anchored molecular catalyst/carbon nano tube hybrid, and obtaining the catalyst compound.
  2. 2. The method for preparing a crown ether substituted nickel phthalocyanine catalyst complex according to claim 1, wherein in the step S1, the nickel salt is Ni (OAc) 2 ·4H 2 O, and the organic solvent is N, N-dimethylethanolamine.
  3. 3. The process for preparing a crown ether substituted nickel phthalocyanine catalyst complex according to claim 1, characterized in that in step S1 the molar ratio of 4, 5-dicyanobenzo-18-crown-6 ether to nickel salt is (3.5-4.5): 1, preferably 4:1.
  4. 4. The method for preparing a crown ether substituted nickel phthalocyanine catalyst complex according to claim 1, wherein in the step S2, the alkali metal salt is potassium hexafluorophosphate in an amount of 10 to 20 times the molar amount of the molecular catalyst, and the first solvent and the second solvent are both N, N-dimethylformamide.
  5. 5. A crown ether substituted nickel phthalocyanine molecular catalyst is prepared by the preparation process of the step S1 in claim 2, and is characterized by comprising the following steps that four 18-crown-6 ether groups are connected to the periphery of a phthalocyanine ring, nickel is used as central metal, and the molecular structural general formula is [ NiPc- (C 12 H 24 O 6 ) 4 ].
  6. 6. The crown ether substituted nickel phthalocyanine catalyst compound is prepared by the preparation method of any one of claims 1-4, and is characterized by comprising the crown ether substituted nickel phthalocyanine molecular catalyst of claim 5 and carbon nanotubes serving as a conductive carrier, wherein the molecular catalyst is supported on the surface of the carbon nanotubes, and the loading amount of the molecular catalyst is 30-70 nmol/mg of the carrier.
  7. 7. Use of the crown ether substituted nickel phthalocyanine catalyst composite of claim 6 in electroreduction of low concentration CO 2 in an acid membrane electrode cell wherein the catalyst composite of claim 6 is employed as a cathode catalyst and carbon dioxide containing gas is passed into a cathode chamber in a bipolar membrane based membrane electrode assembly cell wherein the cathode selectively reduces carbon dioxide to carbon monoxide in an acid environment under reverse bias.
  8. 8. The use of crown ether substituted nickel phthalocyanine catalyst complex according to claim 7 for electroreduction in low concentration CO 2 acid membrane electrode cells, wherein the cathode feed is a carbon dioxide containing gas having a volume concentration of 10% to 40%.
  9. 9. The use of crown ether substituted nickel phthalocyanine catalyst complex according to claim 8 for electroreduction in low concentration CO 2 acid membrane electrode cells, wherein the membrane electrode assembly cells employ bipolar membranes, the electroreduction is carried out under constant current conditions with a current density of 10 to 100 mA/cm 2 , and the faraday efficiency of carbon monoxide is not less than 77% at a carbon dioxide volume concentration of 10% and a current density of 50 mA/cm 2 .
  10. 10. An electro-reduction device for carbon dioxide, comprising a cathode using the catalyst composite of claim 6 as a cathode catalyst.

Description

Crown ether substituted nickel phthalocyanine catalyst and compound thereof, preparation method and application thereof in electrocatalytic reduction of carbon dioxide Technical Field The invention belongs to the technical field of electrochemical catalysis, in particular to a molecular catalyst for electrochemical reduction of carbon dioxide (CO 2 RR), and particularly relates to a nickel phthalocyanine catalyst with tetracrown ether substituent, a preparation method thereof, an electrode containing the catalyst and high-efficiency electroreduction application of the electrode under the condition of low-concentration carbon dioxide. Background With the increasing severity of global climate change, technologies for capturing, utilizing and sequestering CO 2 are receiving great attention. The CO 2 electrocatalytic reduction technology can convert CO 2 into valuable chemicals or fuels such as carbon monoxide, methanol and ethylene, and has a wide application prospect. Currently, catalysts for electrocatalytic reduction of CO 2 mainly include metals (e.g., au, ag), metal oxides, and molecular catalysts (e.g., metal phthalocyanines). Among them, molecular catalysts are receiving a great deal of attention due to their well-defined active center structure and controllable electronic properties. Studies have shown that functional modification of the periphery of phthalocyanine, in particular, introduction of crown ether groups with ion recognition capability, can significantly improve the solubility and dispersibility of the catalyst and the stabilization of the reaction intermediate, thereby improving the catalytic performance. In the prior art, a typical scheme is to load tetra crown ether substituted cobalt phthalocyanine (CoPc-CE) on a multi-wall Carbon Nano Tube (CNTs), and realize single-molecular-level dispersion of a catalyst on a carrier through interaction of crown ether and a host guest of K + ions. The catalyst can realize the CO Faraday Efficiency (FE) of more than 96% and the CO partial current density of 38 mA/cm <2 > under the RHE potential of-0.680V vs in the neutral KHCO 3 electrolyte of an H-type electrolytic cell. However, the technology has three key defects, which severely restrict the industrial application: (1) The product selectivity is limited by the fact that under the condition that the current density of a catalyst taking cobalt as a central metal is higher or the potential of the catalyst is lower, side reactions such as Hydrogen Evolution Reaction (HER) and the like are aggravated, the product distribution is complex (such as H 2、CH3 OH and the like), and the cost of subsequent separation and purification is increased. (2) The lack of acid environmental adaptation the existing studies were all conducted in neutral H-type cells and the performance was not verified in the more industrially promising acid membrane electrode cells (ACIDIC MEA Electrolyzer). The acidic MEA system can fundamentally avoid the formation of carbonate/bicarbonate, thereby greatly improving the single-pass conversion efficiency of CO 2 and being the development direction of the next-generation CO 2 electrolysis technology. (3) The adaptability of low-concentration CO 2 is poor, all performance data are obtained based on saturated CO 2 (100%), and the catalytic activity and stability of the low-concentration CO 2 under the condition of simulating low-concentration CO 2 such as real industrial flue gas (generally containing 10-20% CO 2) are not examined. Low concentrations of CO 2 can lead to severe mass transfer limitations and intense HER competition, resulting in dramatic performance decay. Therefore, the CO 2 electroreduction catalyst which can solve the defects, stably works under the acidic condition, has high adaptability to low-concentration CO 2 and single product selectivity is developed, and has important practical significance and application value. Disclosure of Invention Aiming at the problems, the invention provides a novel crown ether substituted nickel phthalocyanine catalyst, and a preparation method and application thereof. The catalyst shows excellent electrocatalytic reduction performance for a wide concentration range, particularly low concentration CO 2 in an acidic Membrane Electrode (MEA) electrolytic cell based on a bipolar membrane, and can generate carbon monoxide with high selectivity, and the invention aims to solve the following technical problems: 1. Aiming at the problems of complex product and high separation cost of the cobalt phthalocyanine catalyst under high potential, the selective generation of single high-value product (carbon monoxide) is realized by adopting nickel as central metal and introducing tetra crown ether substituent groups, so as to inhibit the generation of byproducts such as hydrogen, methanol and the like. 2. Aiming at the limitation that the prior art only verifies in a neutral H-type electrolytic cell and lacks performance data under an acidic condition,