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CN-121974446-A - TiO2-NTs/Ti4O7-NTs/Ce-Sb-SnO2Composite electrode and preparation method and application thereof

CN121974446ACN 121974446 ACN121974446 ACN 121974446ACN-121974446-A

Abstract

The invention belongs to the technical field of electrochemical water treatment, and particularly relates to a TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode and a preparation method and application thereof, wherein the composite electrode comprises a TiO 2 -NTs substrate, a Ti 4 O 7 -NTs middle layer which grows in situ on the surface of the TiO 2 -NTs substrate and a Ce-Sb co-doped SnO 2 active layer which is coated on the Ti 4 O 7 -NTs middle layer, wherein the molar ratio of Sn to Ce to Sb in the Ce-Sb co-doped SnO 2 active layer is (8-9.4): (0.5-1.5): (0.1-0.5), the composite electrode has a hierarchical structure, the Ti 4 O 7 -NTs middle layer is combined through an enhanced interface of an anchoring effect, and the conductivity and the catalytic activity are synergistically optimized by Ce-Sb double doping, when the composite electrode is used as an anode to be applied to salt-containing organic wastewater degradation, an electrolytic system is constructed to regulate the conductivity, the degradation rate of rhodamine B exceeds 95% in 90min after the electrolytic system is applied to 1-10V direct voltage, the COD removal rate reaches 92%, the continuous service life is ultra-300 h, the salt-resistant energy consumption is low, and the composite electrode is suitable for high-efficient dye-printing and dyeing industry and high-efficiency waste water treatment.

Inventors

  • Xia Qianrou
  • LI CHUN
  • FENG WEIKE
  • ZHANG YUNFEI
  • ZHANG DAN

Assignees

  • 新疆维吾尔自治区环境保护科学研究院

Dates

Publication Date
20260505
Application Date
20260317

Claims (10)

  1. 1. A TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode is characterized by comprising a TiO 2 -NTs substrate, a Ti 4 O 7 -NTs intermediate layer and a Ce-Sb co-doped SnO 2 active layer, wherein the Ti 4 O 7 -NTs intermediate layer is grown on the surface of the TiO 2 -NTs substrate in situ, and the Ce-Sb co-doped SnO 2 active layer is coated on the Ti 4 O 7 -NTs intermediate layer, and the molar ratio of Sn, ce and Sb in the Ce-Sb co-doped SnO 2 active layer is (8-9.4): (0.5-1.5): (0.1-0.5).
  2. 2. The TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode according to claim 1, wherein the continuous service life of the composite electrode in 5000 mg/L NaCl solution is not less than 300 h.
  3. 3. A method for preparing a TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode, which is characterized by comprising the following steps: S1, preparing a TiO 2 -NTs substrate, namely oxidizing titanium foam serving as an anode in glycol electrolyte to enable an ordered TiO 2 nanotube array to grow on the surface of the titanium foam in situ to obtain the TiO 2 -NTs substrate; Preparing a cathode reduction electrolyte, namely performing cathode electrolysis reduction on a TiO 2 -NTs substrate inactive area serving as a cathode in a constant current mode to enable TiO 2 -NTs to grow into Ti 4 O 7 -NTs in situ, and washing and drying to obtain the Ti 4 O 7 -NTs intermediate layer; Preparing a precursor solution according to the molar ratio in claim 1, carrying out sol and gel, uniformly coating the precursor solution on the surface of the Ti 4 O 7 -NTs intermediate layer, then placing the intermediate layer into a muffle furnace for calcining to form a Ce-Sb co-doped SnO 2 active layer, and cooling the intermediate layer to room temperature along with the furnace to obtain the TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode.
  4. 4. The method for preparing a TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode according to claim 3, wherein in step S1, the ethylene glycol electrolyte contains 0.1-1.5wt% NH 4 F and 1-5vol% H 2 O, and the anodic oxidation is carried out for 1-3 hours under a constant pressure of 40-60V.
  5. 5. The method for preparing a TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode according to claim 3, wherein in step S2, the anode is Pt mesh in the cathode electrolytic reduction process, and the cathode reduction electrolyte is prepared from 0.5-2M (NH 4 ) 2 SO 4 and NH 3 Composition is prepared.
  6. 6. The method according to claim 3, wherein in the step S2, the current density is 10-30 mA/cm 2 and the electrolysis time is 1-3 h in the cathode electrolytic reduction process.
  7. 7. The method for preparing a TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode according to claim 3, wherein in the step S3, in the process of preparing the precursor solution, a Sn-containing compound, a Sb-containing compound and a Ce-containing compound are dissolved in an organic solvent, a complexing agent is added, and the mixture is stirred uniformly to form a uniform and transparent precursor solution, wherein the molar ratio of Sn, ce and Sb is (8-9.4): 0.5-1.5): 0.1-0.5.
  8. 8. A method for preparing a TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode according to claim 3, wherein in step S3, during the sol and gel process, the precursor solution is placed in a constant temperature water bath environment at 30 ℃ to 60 ℃, stirred for 2 h to 6h to form a sol, placed in a closed container, and aged at room temperature for 12 h to 24h to form a gel.
  9. 9. The method for preparing a TiO 2 -NTs/Ti 4 O 7 -NTs/Ce-Sb-SnO 2 composite electrode according to claim 3, wherein in step S3, in the coating process, dip-coating method or spin-coating method is used to repeat coating 5-10 times, and after each coating, the coating is placed in a 60 ℃ to 120 ℃ oven to dry 0.5 h to 2 h; In the calcination process, the heating temperature is 450-550 ℃ and the heat preservation time is 1-3 h.
  10. 10. Use of the composite electrode of claim 1 or the composite electrode prepared by claim 3 for degrading salt-containing organic wastewater.

Description

TiO 2-NTs/Ti4O7-NTs/Ce-Sb-SnO2 composite electrode and preparation method and application thereof Technical Field The invention belongs to the technical field of electrochemical water treatment, and particularly relates to a TiO 2-NTs/Ti4O7-NTs/Ce-Sb-SnO2 composite electrode and a preparation method and application thereof. Background The organic wastewater containing salt is widely derived from industrial production processes of printing and dyeing, chemical industry, medicine, pesticide and the like, and is characterized by high salt concentration (total dissolved solid TDS is always more than or equal to 3.5 percent), stable organic pollutant structure (containing more benzene rings, azo bonds and other rigid groups), and poor biodegradability (BOD 5/COD ratio is always lower than 0.3). In the traditional treatment technology, the biological treatment method is easy to be inhibited by a high-salt environment to cause microorganism inactivation, the physical adsorption method only realizes pollutant phase transfer and can not thoroughly mineralize, and the chemical oxidation method has the defects of large dosage of the medicament and high operation cost, so that the industrial advanced treatment requirement is difficult to meet. The electrochemical oxidation method has the technical advantages of strong oxidizing capability, mild reaction condition, no secondary pollution and the like, and becomes a core technical path for treating the salt-containing refractory organic wastewater, and the performance of the electrode material serving as a core carrier of the technology directly determines the degradation efficiency and the operation economy. The SnO 2 -based electrode has high oxygen evolution overpotential (about 1.7V vs SCE), good chemical stability and cost advantage, and is widely focused in the field of electrocatalysis. However, the pure SnO 2 electrode has the inherent defects that the room temperature resistivity is as high asPoor conductivity and low density of surface active sites, severely limiting the practical performance. Doping modification is a key technical means for optimizing the performance of the SnO 2 electrode, wherein Sb is used as a classical n-type doping element, the resistivity of the electrode can be obviously reduced by introducing free carriers, and the optimal doping amount is usually controlled to be 5-10at%. However, a single Sb-doped electrode still has a bottleneck in terms of the number of active sites and long-term operation stability, and is difficult to adapt to the working condition requirements of long-term continuous treatment of high-salt wastewater. The interfacial bonding strength of the electrode substrate and the active layer is a central factor affecting the useful life of the electrode. The active coating of the traditional titanium-based SnO 2 electrode is mostly physically attached to the substrate, and is easy to fall off due to stress in the electrolysis process, so that active components are lost. Ti 4O7 as a novel conductive ceramic material with high conductivity (resistivity)) Compared with chemical inertness, the preparation of Ti 4O7 in the prior art mostly adopts a high-temperature gas reduction or solid carbon source reduction method, and the method has the problems of high energy consumption, severe equipment requirements, difficulty in accurately controlling the structural integrity of the nanotube array and the like. Meanwhile, researches on Ce-Sb double-doped SnO 2 electrodes are mostly based on planar titanium-based or carbon-based carriers, and the problems of low active layer loading capacity, long electron transmission path, high interface impedance and the like exist, and long-term stability data in a high-salt environment do not reach industrial application standards yet. Particularly, aiming at typical refractory pollutants such as phenol, aniline and the like, the mineralization efficiency (TOC removal rate is more lower than 65%) and the energy consumption index (the unit COD treatment energy consumption is more than or equal to 4.5 kWh/kg) of the existing electrode still have a large optimization space. Therefore, the Ce-Sb doped SnO 2 composite electrode for preparing the Ti 4O7 -NTs intermediate layer based on the cathode reduction method is developed, and has important practical significance for breaking through the bottleneck of the prior art. Disclosure of Invention Aiming at the technical problems of high energy consumption, weak binding force between a Ce-Sb doped SnO 2 electrode substrate and an active layer, limited specific surface area, insufficient stability in a high-salt environment, low mineralization efficiency on refractory pollutants such as phenol, aniline and the like in the conventional Ti 4O7 preparation method, the invention provides a TiO 2-NTs/Ti4O7-NTs/Ce-Sb-SnO2 composite electrode and a preparation method thereof, wherein a Ti 4O7 -NTs intermediate layer is prepared by a cathode reduction method (adop