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CN-121976233-A - NiO/Cu rich in selenium vacancy2Se heterostructure catalyst and preparation method and application thereof

CN121976233ACN 121976233 ACN121976233 ACN 121976233ACN-121976233-A

Abstract

The invention relates to the technical field of electrocatalytic materials, and mainly discloses a NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies, a preparation method and application thereof, wherein the catalyst comprises a NiO phase and a Cu2Se phase to form a heterojunction structure, and the selenium vacancies are introduced into a Cu 2 Se crystal lattice, and the chemical general formula is represented as NiO/Cu2Se-V Se . In the electrolyte system of 0.5M KOH+50 mM NH 3 .H2O, the initial potential is as low as 1.35V, which is obviously superior to a NiO/CuO control sample without introducing selenium vacancy, and is also superior to most of reported non-noble metal-based AOR catalysts, in addition, the catalyst can efficiently and highly selectively directionally convert ammonia into nitrite, the catalyst can still maintain excellent catalytic performance after 96 hours of continuous operation, firstly, selenate species formed on the surface stabilize nickel active sites in a proper oxidation state, excessive generation of NiOOH and structural dissolution caused by NiOOH are effectively inhibited, and meanwhile, the stable heterostructure is used as a firm framework, so that aggregation and loss of active components in long-term operation are prevented.

Inventors

  • HU WEI
  • DU HEBAO
  • PENG MIN
  • ZHAO XI
  • HE WEI
  • PENG LIXIONG
  • ZHAO YUXUAN

Assignees

  • 上海澳思净科技有限公司

Dates

Publication Date
20260505
Application Date
20251230

Claims (9)

  1. 1. The NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies is characterized in that the catalyst comprises a heterojunction structure formed by a NiO phase and a Cu 2 Se phase, and the selenium vacancies are introduced into a Cu 2 Se crystal lattice, wherein the chemical general formula of the catalyst is NiO/Cu 2 Se-V Se ; the atomic ratio of Ni element to Cu element in the catalyst is 0.5:1-2:1.
  2. 2. A catalyst of NiO/Cu 2 Se heterostructure rich in selenium vacancies as claimed in claim 1, wherein the atomic ratio of Ni to Cu is 1:1.
  3. 3. A method for preparing the NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies according to claim 1, comprising the steps of: s1, dissolving soluble nickel salt, soluble copper salt and a structure directing agent in deionized water, and stirring to form a uniform solution; S2, carrying out solvothermal reaction on the solution, wherein the reaction temperature is 80-120 ℃, the reaction time is 6-12 hours, collecting a precipitate after natural cooling, and washing and drying to obtain a Ni (OH) 2 /Cu(OH) 2 nano rod precursor; s3, calcining the precursor for 2-4 hours at 450-550 ℃ under the protection of argon gas to convert the precursor into a NiO/CuO nanoflower structure with a rough surface; S4, placing the NiO/CuO and selenium powder in different temperature areas of a tube furnace, and carrying out selenizing reaction for 1-3 hours at 450-550 ℃ in argon gas flow to promote the conversion of copper oxide into selenide, so as to form stacked NiO/Cu 2 Se nanospheres; S5, annealing the NiO/Cu 2 Se composite in argon at 400-500 ℃ for 20-60 minutes to form selenium vacancies in Cu 2 Se crystal lattice, and obtaining the NiO/Cu 2 Se-V Se catalyst.
  4. 4. The method for preparing a selenium vacancy-rich NiO/Cu 2 Se heterostructure catalyst according to claim 3, wherein in the step S1, the soluble nickel salt is nickel nitrate, the soluble copper salt is copper nitrate, and the structure directing agent is hexamethylenetetramine.
  5. 5. The method for preparing a NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies according to claim 4, wherein the amounts of the substances of the nickel salt and the copper salt in the step S1 are 2.5: 2.5 mmol, the structure directing agent is 10: 10 mmol, and the deionized water is 40: 40 mL.
  6. 6. The method for preparing the NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies according to claim 5, wherein the solvothermal reaction temperature in the step S2 is 100 ℃, the reaction time is 10 hours, the calcination temperature in the step S3 is 500 ℃ and the time is 3 hours, the selenization temperature in the step S4 is 500 ℃ and the time is 2 hours, and the annealing temperature in the step S5 is 450 ℃ and the time is 30 minutes.
  7. 7. The use of the NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies in an electroammoxidation reaction as set forth in claim 1, wherein the catalyst is used as an anodic electrocatalyst for electrochemically oxidizing NH 3 in an aqueous ammonia solution to nitrite ions [ ] )。
  8. 8. The use of a selenium vacancy-rich NiO/Cu 2 Se heterostructure catalyst according to claim 7, wherein the ammonia-containing aqueous solution is a 0.1-1.0M KOH alkaline electrolyte containing 50 mM NH 3 ·H 2 O.
  9. 9. The use of a selenium vacancy-rich NiO/Cu 2 Se heterostructure catalyst according to claim 7, wherein the operating potential of the ammoxidation reaction is in the range of 1.35 to 1.70V.

Description

NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancy, preparation method and application thereof Technical Field The invention relates to the technical field of electrocatalytic materials, in particular to a NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies, a preparation method and application thereof. Background Ammonia (NH 3) is one of the key pollution sources for water eutrophication, and is widely used in agricultural wastewater, industrial wastewater and municipal sewage. Aiming at the control and recycling requirements of ammonia nitrogen pollution, the ammonia electrooxidation reaction (AOR) is widely paid attention as a green electrochemical technology. The reaction can efficiently convert ammonia in the wastewater into high-added-value nitrogen chemicals such as nitrite and the like under the condition of normal temperature and normal pressure, is coupled with cathodic Hydrogen Evolution Reaction (HER), synchronously realizes pollutant removal and clean energy (H 2) production, and has environmental benefit and resource recovery potential. However, this technology still faces a key bottleneck in the development of high performance catalysts in practical popularization. Currently, research and applications in this area are faced with a number of challenges. First, noble metal catalysts (e.g., pt, ir, etc.) have excellent intrinsic activity for ammoxidation, but their high cost and resource scarcity severely limit their large-scale applications. More importantly, the catalyst is easy to be strongly adsorbed by a reaction intermediate (such as N 2Hx) in the operation process, so that active sites are poisoned, and the stability is obviously reduced. To reduce material costs, researchers have turned to non-noble metal systems where nickel-based catalysts are considered potential candidates due to their strong adsorption capacity for NH 3. However, although the NiOOH phase generated in situ under alkaline conditions can catalyze AOR, it is also a high active site for Oxygen Evolution Reaction (OER), so that severe OER competition occurs in a high potential region, and current efficiency and nitrite selectivity are greatly reduced. On the other hand, the copper-based catalyst has moderate adsorption energy on the nitrogen-containing intermediate, is favorable for N species desorption, but has weaker adsorption capacity on NH 3 and slow proton transfer kinetics, so that the overall AOR activity and reaction rate are difficult to meet the actual demands. This reveals that a single metal component is difficult to optimize at the same time in multiple links such as reactant adsorption, intermediate conversion, and product desorption. The problem is that most of the existing catalysts lack an effective mechanism for accurately regulating and controlling the reaction path, so that the OER competition problem cannot be fundamentally solved, and the reaction cannot be actively guided to be carried out towards the direction of generating specific products (such as nitrite). Therefore, developing a non-noble metal AOR catalyst which can simultaneously achieve high activity, high selectivity, excellent stability and low cost, and can inhibit side reactions and directionally regulate and control reaction paths through precise design of the electronic structure and surface properties of the catalyst has become a core key and urgent need for promoting the technology to go to practical application. For the problems in the related art, no effective solution has been proposed at present. Disclosure of Invention The invention aims to provide a NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies, a preparation method and application thereof, so as to solve the problems in the background technology. In order to achieve the above purpose, the present invention provides the following technical solutions: The catalyst comprises a heterojunction structure formed by a NiO phase and a Cu 2 Se phase, wherein selenium vacancies are introduced into a Cu 2 Se crystal lattice, and the chemical formula is represented as NiO/Cu 2Se-VSe; the atomic ratio of Ni element to Cu element in the catalyst is 0.5:1-2:1. Further, the atomic ratio of Ni to Cu is 1:1. The preparation method of the NiO/Cu 2 Se heterostructure catalyst rich in selenium vacancies specifically comprises the following steps: s1, dissolving soluble nickel salt, soluble copper salt and a structure directing agent in deionized water, and stirring to form a uniform solution; S2, carrying out solvothermal reaction on the solution, wherein the reaction temperature is 80-120 ℃, the reaction time is 6-12 hours, collecting a precipitate after natural cooling, and washing and drying to obtain a Ni (OH) 2/Cu(OH)2 nano rod precursor; s3, calcining the precursor for 2-4 hours at 450-550 ℃ under the protection of argon gas to convert the precursor into a NiO/CuO nanoflower structure with a rough surface; S4, placing the NiO/CuO and selenium powder