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CN-121990608-A - Bi (Bi)2MoO6/TiO2Composite photo-anode material and preparation method and application thereof

CN121990608ACN 121990608 ACN121990608 ACN 121990608ACN-121990608-A

Abstract

The invention provides a Bi 2 MoO 6 /TiO 2 composite photo-anode material, a preparation method and application thereof, belonging to the technical field of metal corrosion and protection. The Bi 2 MoO 6 is deposited on the surface of the TiO 2 nanotube array through one-step hydrothermal reaction by adopting a heterojunction engineering strategy to prepare the Bi 2 MoO 6 /TiO 2 composite photo-anode with the S-shaped heterojunction structure, and the material is formed by compositing the bottom TiO 2 nanotube array and the top Bi 2 MoO 6 nano-particles, and has the advantages of excellent light absorption utilization rate and photoelectric conversion efficiency, remarkable improvement of photo-generated carrier separation and migration efficiency and stronger long-term stability. The novel photo-anode material is applied to photoelectrochemical cathode protection of metals/alloys, can realize rapid and efficient protection of nickel-plated magnesium alloys, effectively inhibits metal corrosion, and provides a novel photo-anode material with excellent performance for the field of metal corrosion prevention.

Inventors

  • XIE ZHIHUI
  • WEN YU
  • YONG QIWEN
  • PU DONGMEI
  • LIU YUE

Assignees

  • 西华师范大学

Dates

Publication Date
20260508
Application Date
20260210

Claims (10)

  1. 1. The hydrothermal preparation method of the Bi 2 MoO 6 /TiO 2 composite photo-anode material is characterized by comprising the following steps of: Step 1), polishing the Ti foil, taking the Ti foil as a working electrode, connecting a direct current power supply to a platinum electrode as a counter electrode, performing anodic oxidation in a constant potential mode, and sequentially washing, drying and annealing the obtained TiO 2 to obtain a TiO 2 nanotube array; Step 2), mixing a molybdenum source, a bismuth source and water, dispersing, and regulating the pH value of the system to obtain a mixed solution; And 3) mixing the mixed solution with the platy TiO 2 nanotube array, then carrying out reaction, and then washing and drying sequentially to obtain the Bi 2 MoO 6 /TiO 2 photo-anode.
  2. 2. The method for preparing Bi 2 MoO 6 /TiO 2 composite photoanode material according to claim 1, wherein in step 1), the chemical polishing solution used for polishing includes NH 4 F、H 2 O 2 、H 2 O and HNO 3 ; Wherein, the ratio of NH 4 F、H 2 O 2 、H 2 O to HNO 3 1.5-2 g, 20-30 mL, 8-15 mL, 20-30 mL; The polishing time is 60-120 s.
  3. 3. The hydrothermal preparation method of the Bi 2 MoO 6 /TiO 2 composite photo-anode material according to claim 1 or 2, wherein in the step 1), the constant potential mode voltage is 50-60V, and the anodic oxidation time is 50-70 min; The anodic oxidation is carried out in an anodic oxidation electrolyte, the anodic oxidation electrolyte comprises NH 4 F、H 2 O and ethylene glycol, and the dosage ratio of NH 4 F、H 2 O to ethylene glycol is 0.2~0.3 g:2~5mL:35~40mL.
  4. 4. The hydrothermal preparation method of the Bi 2 MoO 6 /TiO 2 composite photo-anode material according to claim 3, wherein in the step 1), the drying temperature is 50-70 ℃, the annealing temperature is 400-500 ℃, and the annealing time is 1.5-3 hours; the annealing is performed in an air atmosphere, and the temperature rising rate from room temperature to the annealing temperature is 3-6 ℃ per minute.
  5. 5. The method for hydrothermal preparation of Bi 2 MoO 6 /TiO 2 composite photoanode material according to claim 1 or 4, wherein in step 2), the molybdenum source comprises Na 2 MoO 4 2H 2 O, bismuth source including Bi (NO 3 ) 3 5H 2 O; The dosage ratio of the molybdenum in the molybdenum source to the bismuth in the bismuth source to the water is 1mmol to 2mmol to 50-80 mL according to the mass of the molybdenum and the bismuth; The dispersion is carried out under the ultrasonic condition, and the ultrasonic time is 20-40 min.
  6. 6. The hydrothermal preparation method of the Bi 2 MoO 6 /TiO 2 composite photoanode material according to claim 5, wherein in the step 2), the pH of the system is 6.0-10.0, and NH is adopted 3 H 2 O regulates the pH of the system.
  7. 7. The hydrothermal preparation method of the Bi 2 MoO 6 /TiO 2 composite photo-anode material according to claim 1, 4 or 6, wherein in the step 3), the reaction temperature is 150-180 ℃, and the reaction time is 10-14 h; the drying temperature is 50-70 ℃, and the drying time is 8-10 h.
  8. 8. The Bi 2 MoO 6 /TiO 2 composite photo-anode material prepared by the preparation method of claim 1-7.
  9. 9. The use of Bi 2 MoO 6 /TiO 2 composite photoanode material as claimed in claim 8 for protecting metals/alloys, characterized in that Bi 2 MoO 6 /TiO 2 composite photoanode material is used as anode and protected metals/alloys are used as cathode, and the photo-generated cathodic protection of metals/alloys is achieved under irradiation of sunlight.
  10. 10. The use of Bi 2 MoO 6 /TiO 2 composite photoanode material as claimed in claim 9, wherein the alloy comprises nickel-plated magnesium alloy.

Description

Bi 2MoO6/TiO2 composite photo-anode material and preparation method and application thereof Technical Field The invention relates to the technical field of metal corrosion and protection, in particular to a Bi 2MoO6/TiO2 composite photo-anode material, a preparation method and application thereof. Background The photo-generated cathodic protection technique (PECCP) has received much attention as an almost "zero energy consumption" corrosion protection technique. The photo-generated cathode protection technology has great application value in severe service scenes such as ocean cross-sea bridges, aviation spacecraft electronic equipment shells and the like, and has high requirements on the light absorption utilization rate, carrier separation and transmission efficiency and long-term stability of the photo-anode in the technology field. Anatase type TiO 2 is a hot spot material in the PECCP field, is used as a wide forbidden band semiconductor (Eg > 3.0 eV), has low photoelectric conversion efficiency due to ultraviolet light response characteristic (only accounting for 4% of solar spectrum) and high carrier recombination rate, and is difficult to meet the high-efficiency protection requirement of special components such as nickel-plated magnesium alloy, and therefore, the photoelectrochemical property of the anatase type TiO 2 needs to be optimized through precise modification. Bismuth molybdate (Bi 2MoO6) is an inorganic semiconductor material formed by alternately stacking [ Bi 2O2]2+ layers and perovskite [ MoO 4]2- layers), has a unique Aurivillius structure, shows good visible light response, proper band gap (2.7 eV) and excellent chemical stability, and is one of preferred materials for TiO 2 modification. At present, a small amount of researches try to construct a composite system by adopting Bi 2MoO6 to modify TiO 2, but the existing Bi 2MoO6/TiO2 composite material has two general defects that firstly Bi 2MoO6 is in a form of a block, sheet or disordered agglomerated particles, the interface combination of the Bi 2MoO6 and a TiO 2 nanotube array is not tight, so that the charge transfer resistance is large, secondly the Bi 2MoO6 energy band structure is not precisely regulated and controlled, the matching degree of the Bi 2MoO6 energy band structure and the energy band offset of TiO 2 is insufficient, most of the composite materials form a traditional II type heterojunction after being compounded, the high-efficiency separation of photo-generated electron-hole pairs cannot be realized, and therefore, the problem of slow carrier migration dynamics cannot be fundamentally solved, and the high-performance requirement of a PECCP technology on a photo-anode is difficult to adapt. The magnesium alloy has the characteristics of small density, high specific strength and the like, has wide application prospect in the fields of aerospace, transportation, 3C electronics, military industry and the like, and is known as a green engineering material in the 21 st century. However, the susceptibility to corrosion is one of the important factors limiting the application of magnesium alloys. Electroless nickel plating is a common surface treatment method for magnesium alloy, and simultaneously gives the member advantages of good wear resistance, high hardness and the like, but has obvious disadvantages of easy occurrence of galvanic corrosion. Chinese patent (202110428189.4) proposed to delay the occurrence of galvanic corrosion of nickel-plated magnesium alloy by PECCP technique. However, the Cu 2 O modified TiO 2 photoanode employed in this patent has limited photoelectrochemical properties and limited effect of inhibiting galvanic corrosion. Aiming at the current situation, the Bi 2MoO6/TiO2 composite photo-anode with an S-type charge transfer mechanism is successfully constructed by adopting high-pressure hydrothermal reaction and optimizing and controlling the morphology and the energy band structure of Bi 2MoO6. Compared with the existing Bi 2MoO6/TiO2 composite material, the Bi 2MoO6 in the application presents the morphology of directionally agglomerated nano particles, can form tight interface contact with the TiO 2 nanotube array, and greatly reduces the interface charge transfer resistance. Meanwhile, by changing the pH value of the hydrothermal reaction system, the precise regulation and control of the Bi 2MoO6 energy band position deviation is realized, so that an adaptive energy band structure is formed by the Bi 2MoO6 energy band position deviation and the TiO 2, and the limitation of the traditional II type heterojunction is broken through. The Bi 2MoO6/TiO2 composite material can not only efficiently separate photogenerated electron-hole pairs and inhibit carrier recombination, but also maintain the strong reducibility of photogenerated electrons and the strong oxidability of holes through an S-type charge transfer mechanism, thereby remarkably improving the photoelectrochemical property of the