阅读说明：本技术 一种氧化铈纳米棒阵列/石墨烯复合材料的制备方法及其在光阴极保护中的应用 (Preparation method of cerium oxide nanorod array/graphene composite material and application of cerium oxide nanorod array/graphene composite material in photocathode protection ) 是由 姚超 左士祥 严向玉 李霞章 刘文杰 王灿 叶里祥 吴红叶 于 2020-04-29 设计创作，主要内容包括：本发明涉及一种氧化铈纳米棒阵列/石墨烯复合材料的制备方法及其在光阴极保护中的应用,本发明以导电基质为衬底,通过电沉积法在衬底上生长CeO<Sub>2</Sub>纳米棒阵列。然后以SnCl<Sub>2</Sub>乙醇溶液活化CeO<Sub>2</Sub>纳米棒阵列,将Sn<Sup>2+</Sup>沉积于CeO<Sub>2</Sub>纳米棒阵列上,浸入GO溶液中,通过Sn<Sup>2+</Sup>将GO还原成rGO,同时Sn<Sup>2+</Sup>与rGO静电吸附,使得CeO<Sub>2</Sub>纳米棒阵列连接在石墨烯上片,构建氧化铈纳米棒阵列/石墨烯复合材料。氧化铈纳米棒阵列结构不仅能够提高光吸收率,在光照下能有效促进电子-空穴的分离和载流子的定向传输效率,将片状材料的物理阻隔和传统光阴极防腐相结合,发挥了两者的协同作用,进一步提高了防腐性能。(The invention relates to a preparation method of a cerium oxide nanorod array/graphene composite material and application thereof in photocathode protection 2 A nanorod array. Then SnCl 2 Ethanol solution activation of CeO 2 Nanorod array of Sn 2+ Deposited on CeO 2 On nanorod arrays, immersed in GO solution, through Sn 2+ Reduction of GO to rGO, with Sn 2+ Electrostatically adsorb with rGO to make CeO 2 Nano-rodThe array is connected with the graphene upper sheet to construct the cerium oxide nanorod array/graphene composite material. The cerium oxide nanorod array structure can improve light absorption rate, effectively promote electron-hole separation and directional carrier transmission efficiency under illumination, combine physical barrier of a sheet material with traditional photocathode corrosion prevention, exert synergistic effect of the two and further improve corrosion prevention performance.)

1. A preparation method of a cerium oxide nanorod array/graphene composite material is characterized by comprising the following steps:

(1) using a conductive substrate as a substrate, a cerium salt solution as an electrolyte, potassium chloride as an auxiliary electrolyte and ammonium salt as a stabilizer, and performing electrodeposition at 50-90 ℃ and 0.5-5.5 mA/cm²Is subjected to potential deposition for 80-160 min at the current density of CeO₂Nucleation on seed layer to grow CeO₂The nanorod array is directly subjected to the next operation without removing the substrate after the deposition is finished;

(2) using GO as raw material and SnCl₂Activating CeO with ethanol solution as activator₂Nano rod array prepared from Sn²⁺Deposited on CeO₂Immersing the nano-rods on the nano-rod array into GO aqueous solution, stirring for 0.5-3.5 h at 50-90 ℃, and passing through Sn²⁺Reduction of GO to rGO, with Sn²⁺Electrostatically adsorb with rGO to make CeO₂The nanorod array is connected to the graphene upper sheet and is coated with Na₂SO₄And washing with deionized water, and drying in vacuum at 50-90 ℃ to obtain the cerium oxide nanorod array/graphene composite material.

2. The method for preparing the cerium oxide nanorod array/graphene composite material according to claim 1, wherein the method comprises the following steps: the substrate is one of Ti, ITO conductive glass and FTO conductive glass.

3. The method for preparing the cerium oxide nanorod array/graphene composite material according to claim 1, wherein the method comprises the following steps: the cerium salt is one of cerium nitrate, ammonium cerium nitrate and cerium chloride; the stabilizer is one of ammonium chloride, ammonium nitrate, ammonium acetate and hexamethylenetetramine solution.

4. The method for preparing the cerium oxide nanorod array/graphene composite material according to claim 1, wherein the method comprises the following steps: the amount ratio of the electrolyte to the stabilizer is 1: 2-1: 0.5.

5. The cerium oxide nanorod array/graphene composite material prepared by the method according to any one of claims 1-4, and application of the cerium oxide nanorod array/graphene composite material in photocathode protection.

Technical Field

The invention belongs to the technical field of photocathode protection materials, and relates to a preparation method of a cerium oxide nanorod array/graphene composite material and application of the cerium oxide nanorod array/graphene composite material in photocathode protection.

Background

The metal corrosion means that the metal material is damaged by the action of surrounding media, the problems caused by the metal material are caused in various industries, and resource waste caused by the metal material brings huge loss to national economy. The traditional anticorrosion technology mainly comprises the following steps: the corrosion inhibitor adding method, the anticorrosive coating method and the electrochemical protection method still have the problems of relatively complex process, high cost, short service life or single anticorrosive performance and the like, and compared with the traditional external current cathode and sacrificial anode method anticorrosive technology, the photoelectrochemical cathode protection technology has the advantages of no need of electric energy consumption, recyclable photoanode material, low price, environmental protection, no pollution and the like. The selection of the photocathode protection material is particularly important.

Cerium oxide (CeO)₂) Is a narrow bandgap n-type semiconductor material commonly used in the field of metal photocathode protection, the Conduction Band (CB) potential is more negative than the self-corrosion potential (ESS ═ 0.33eV) of some metals such as 304 stainless steel, photo-generated electrons can be conducted across the energy barrier to the protected metal, and the Valence Band (VB) potential is higher than H₂The oxidation potential of O is corrected, and the generated holes can be changed by OH^-Trapping to inhibit recombination of self-electrons and holes, and the ability to store electrons in photocathode protectionIn addition, cerium oxide is excellent in stability (corrosion resistance) and Ce (iv) -Ce (iii) redox cycle. However, the problem that the photo-generated electron hole is easy to recombine exists in the cerium oxide, and the problem is mainly solved by constructing a heterojunction structure and compounding a graphite phase carbon material at present. Reduced graphene oxide (rGO) is a novel two-dimensional nano-sheet-like carbon nanomaterial, has a large specific surface area, excellent physical barrier property, high chemical stability and high electron mobility, and is widely applied to the field of anticorrosive coatings.

Cerium oxide in the existing cerium oxide/graphene composite material is generally granular, cerium oxide nanoparticles cannot rapidly and effectively conduct electrons, and the constructed cerium oxide nanorod array can effectively conduct electrons.

Disclosure of Invention

The invention aims to provide a preparation method of a cerium oxide nanorod array/graphene composite material and an application of the cerium oxide nanorod array/graphene composite material in photocathode protection, and aims to solve the technical problems that proper raw materials and a preparation process flow of the cerium oxide nanorod array/graphene composite material are selected, and on one hand, an ordered one-dimensional cerium oxide nanorod array structure can improve light absorption rate, effectively promote separation of electrons and holes and directional transmission efficiency of carriers under illumination, release stored electrons in the dark to protect protected metal, and effectively reduce curling and stacking of graphene. On the other hand, due to the excellent conductivity of the graphene, photo-generated electrons can be quickly transferred to 304 stainless steel, the photo-generated electrons and holes are effectively prevented from being compounded, and the sheet structure has physical barrier and can reduce permeation of corrosion factors.

The invention also provides a preparation method of the cerium oxide nanorod array/graphene composite material, which comprises the following steps:

the invention relates to a cerium oxide nanorod array/graphene composite material, which is a composite material (CeO) obtained by forming a cerium oxide nanorod array on graphene by taking flaky graphene as a carrier₂NRA/rGO) and use of the composite in photocathode protection.

The method comprises the following specific steps

(1) Using a conductive substrate as a substrate, 0.01-0.05 mol/L cerium salt solution as an electrolyte, 0.05-0.35 mol/L potassium chloride as an auxiliary electrolyte, 0.1-0.5 mol/L ammonium salt as a stabilizer, and performing electrodeposition at 50-90 ℃ and 0.5-5.5 mA/cm²Is subjected to potential deposition for 80-160 min at the current density of CeO₂Nucleation on seed layer to grow CeO₂A nanorod array. And (3) directly carrying out the next operation without removing the substrate after the operation of the step (1) is finished.

Wherein the substrate is one of Ti, ITO conductive glass and FTO conductive glass; the cerium salt is one of cerium nitrate, ammonium cerium nitrate and cerium chloride; the stabilizer is one of ammonium chloride, ammonium nitrate, ammonium acetate and hexamethylenetetramine solution. The ratio of the amount of the electrolyte to the stabilizer substance is 1:2 to 1:0.5, and the ratio of the amount of the electrolyte to the amount of the auxiliary electrolyte substance is 1:0.1 to 1: 10.

(2) Graphite Oxide (GO) is prepared from natural graphite by a modified Hummers method, the GO is used as a raw material, and 50-150 mL0.025-0.075 mol/L of SnCl₂Activating CeO with ethanol solution as activator₂Nanorod array of Sn²⁺Deposited on CeO₂Immersing the nano-rods on the nano-rod array into GO aqueous solution, stirring for 0.5-3.5 h at 50-90 ℃, and passing Sn²⁺Reduction of GO to rGO, with Sn²⁺Electrostatically adsorb with-OH, -COOH on rGO to make CeO₂The nanorod array is attached to a graphene sheet with Na₂SO₄And washing with deionized water to remove SnO₂And (3) drying the particles at 50-90 ℃ in vacuum to obtain the cerium oxide nanorod array/graphene composite material.

The invention has the beneficial effects that:

1. the cerium oxide nanorod array is prepared by an electrodeposition method, the cerium oxide nanorod array is uniformly dispersed due to the ordered nanorod array, and the cerium oxide nanorod array/graphene is obtained by an electrostatic adsorption method, wherein the cerium oxide nanorod array can effectively inhibit the graphene sheets from curling and stacking, and meanwhile, the preparation method is simple and raw materials are easy to obtain.

2. The one-dimensional cerium oxide nanorod array can effectively improve the light absorption rate in the photocathode protection, can promote the separation of electron-hole and the directional transmission of carriers under the illumination, and can release the stored electrons in the dark to provide protection for the protected metal. In addition, the graphene can improve the transmission rate of electrons, promote the separation of electrons and holes, and can obstruct and slow down the permeation of corrosion factors such as oxygen, water and ions. The physical barrier of the sheet material is combined with the traditional photocathode corrosion prevention, the synergistic effect of the sheet material and the traditional photocathode corrosion prevention is exerted, and the corrosion prevention performance is further improved.

Drawings

FIG. 1 is a scanning electron micrograph of a composite prepared in example 1;

FIG. 2 is a plot of Tafel polarization in dark and light for example 1, comparative example 2, and bare 304 SS;

as can be seen from FIG. 2, in example 1, the potential is the largest, the current density is the largest, and the photocathode protection effect is better.

FIG. 3 is a graph of photocurrent versus time for example 1, comparative example 1, and comparative example 2;

as can be seen from fig. 3, in the case of light irradiation, example 1 has more excellent photoresponse capability and electron-hole separation efficiency, the surface-obtained structure is more favorable for obtaining higher photoelectric conversion efficiency, and then the xenon lamp is turned off, and example 1, comparative example 1 and comparative example 2 can still release electrons in the dark, so that the photocurrent density is slowly reduced.

Detailed Description