CN102485968A - Preparation method of zinc-doped titania nanotube array - Google Patents

Abstract

The invention belongs to the technical field of photoelectric materials and specially, relates to a preparation method of a zinc-doped titanium dioxide nano-tube array. The preparation method comprises the following steps that 1, an electrolyte of a HF aqueous solution having HF content of 0.3 to 1.0 wt%, an anode of pure titanium foil subjected to surface pretreatment and a cathode of a Pt sheet undergo an electrochemical anodization reaction under direct voltage of 10 to 50V to produce a titanium dioxide nano-tube array; and the titanium dioxide nano-tube array as a cathode, an anode of a platinum sheet and an electrolyte of a Zn(NO3) solution having concentration of 0.1 to 0.5mol/L undergo an electrochemical deposition reaction under direct voltage of 0.3 to 1.0V so that zinc is added into titanium dioxide nano-tube layers and the zinc-doped titanium dioxide nano-tube array is obtained. The preparation method provided by the invention has the advantages that ion implantation time is short; and doped ions Zn<2+> can enter into a titanium dioxide nano-tube under a electric field force and capillary action so that the zinc-doped titanium dioxide nano-tube array having good photoelectric properties and a light absorption range widen to a visible light range is prepared.

Description

Preparation method of zinc-doped titania nanotube array

technical field

The invention belongs to the technical field of optoelectronic materials, and in particular relates to a method for preparing a zinc-doped titanium dioxide nanotube array by using an anodic oxidation method, in particular to a zinc-doped titanium dioxide nanotube array with good photoelectric performance prepared by a subsequent electrochemical deposition method. Tube array method.

Background technique

Titanium dioxide is an important inorganic functional material. It has broad application prospects in the storage and utilization of solar energy, photoelectric conversion, photochromism and photocatalytic degradation of pollutants in the atmosphere and water, because of its rich raw material resources and low price. , and non-toxic, it is a research hotspot in the world in recent years. Titanium dioxide mainly has three crystal forms: anatase, rutile and unstable brookite. Due to different crystal forms, the band gap of titanium dioxide is distributed around 3.0-3.2, and it can only absorb 3-5% of the solar spectrum. Ultraviolet part, but almost no absorption of visible light. The ordered titanium dioxide nanotube array has obvious quantum confinement effect, highly ordered orientation structure and large specific surface area, which can effectively improve the interface separation of electrons and holes and the directional transport efficiency of carriers, making it in Dye-sensitized cells, photo(electric) catalytic degradation of pollutants, sensors and other technical fields have important application prospects.

At present, the main methods used to prepare doped titania nanotube arrays include electrolytic modification method, impregnation method and so on. Among these methods, the electrolytic solution modification method changes the charge migration velocity in the electrolyte due to the addition of metal ions, increases the current, and the complexation reaction between some ions and F ^- reduces the F ^- concentration in the electrolyte, It is not conducive to the reaction, so it is not universal; in the impregnation modification, the main driving force of ion implantation is capillary action, this method takes a long time, and the ions are not easy to enter the titanium dioxide nanotubes. Therefore, the present invention proposes a new ion implantation method to dope and modify titanium dioxide nanotubes, that is, the subsequent electrochemical deposition method, so that ions are effectively injected into the titanium dioxide nanotubes under the dual effects of capillary and electric field force, The doping amount and the existence of doping ions can be controlled by adjusting the concentration of doping ions and the deposition voltage, which is an effective doping modification method.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing a zinc-doped titanium dioxide nanotube array with good photoelectric performance. The tube size and tube diameter are uniform and controllable, thermal stability and photoelectric performance are good, and can be widely used in the field of photoelectric materials.

In order to solve the above-mentioned technical problems, the invention provides a method for preparing a zinc-doped titanium dioxide nanotube array with good photoelectric properties, comprising the following steps:

(1) Polish the pure titanium foil until there is no scratch on the surface, clean it and set aside;

(2) Preparation of electrolyte: the electrolyte is a mixed solution prepared by hydrofluoric acid hydrofluoric acid and deionized water with a HF content of 40wt%, and the content of HF in the electrolyte is 0.3wt%-1.0wt%;

(3) The surface-treated pure titanium foil is used as the anode, the platinum sheet is used as the cathode, connected to a DC stabilized power supply, and electrochemically anodized in the HF electrolyte, keeping the distance between the two electrodes at 20-50mm, and the anodizing voltage 10-50V, the oxidation time is 1-4h, and the amorphous titanium dioxide nanotube array is prepared;

(4) Preparation of zinc-doped titania nanotube array: use amorphous titania nanotube array as cathode, platinum sheet as anode, and 0.1-0.5mol/L Zn(NO ₃ ) ₂ solution as electrolyte. Electrochemical deposition is carried out at a DC voltage of 1.0V for 20-60min, and Zn ²⁺ enters the titanium dioxide nanotubes under the action of electric field force and capillary action;

(5) Put the electrochemically deposited titanium dioxide nanotube array into a muffle furnace, and anneal at a constant temperature of 450-600° C. for 2-4 hours to obtain the zinc-doped titanium dioxide nanotube array.

The optimum DC voltage for the anodic oxidation is 20-40V.

The optimum DC voltage of the electrochemical deposition is 0.4-0.7V, and the optimum concentration of Zn(NO ₃ ) ₂ in the electrolyte is 0.1-0.3mol/L.

The invention provides a method for preparing a zinc-doped titanium dioxide nanotube array. When the voltage is low and the oxidation time is short, the nanotubes are arranged neatly and the pore size distribution is uniform; when the deposition voltage is low and the deposition time is short, it can be Zinc-doped titanium dioxide nanotubes with high photoelectric activity are obtained; the lower the calcination temperature, the more uniform the pore size distribution of the formed zinc-doped titanium dioxide nanotubes and good surface morphology.

Main advantage of the present invention:

Compared with the existing method for preparing metal-doped titanium dioxide nanotube arrays, the present invention adopts a new doping method, that is, the titanium dioxide nanotube arrays are doped and modified by the subsequent electrochemical deposition method, which can make Zn ²⁺ enters into the interior of titanium dioxide nanotubes under the dual effects of capillary action and electric field force; the amount of Zn ²⁺ doped and its existence in the nanotubes can be realized by adjusting the DC voltage during the electrochemical deposition process. Controllable; the prepared titanium dioxide nanotubes are evenly distributed and arranged neatly, and are directly connected to the metal titanium substrate, and the combination is firm; the titanium dioxide nanotube array has an ordered structure and high quantum effect; the prepared sample is modified with the electrolyte Compared with the prepared zinc-doped titanium dioxide nanotube array, it has better photoelectric performance and can be widely used in the fields of photoelectrocatalysis and dye-sensitized solar cells.

Description of drawings

Figure 1 is a scanning electron microscope image of a zinc-doped titania nanotube array

The scanning electron microscope figure of the zinc-doped titanium dioxide nanotube array of the present invention adopts a JEOL JSM-6700F scanning electron microscope, and the accelerating voltage is 3.0KV, and the magnification is 30000 times (a) and 150000 times (b) under the condition of shooting .

Figure 2 is the X-ray diffraction pattern of titanium dioxide nanotube arrays

The X-ray diffraction pattern of the zinc-doped titanium dioxide nanotube array of the present invention adopts a SEMENS D5000 X-ray diffractometer, and the test conditions: the target material is Cu, the tube voltage is 35KV, the tube current is 30mA, and the scanning range is 10° to 80°. The step size is 0.02°, and the integration time is 0.2s. Fig. 2(a) is an X-ray diffraction pattern of a pure titania nanotube array, and Fig. 2(b) is an X-ray diffraction pattern of a zinc-doped titania nanoarray tube.

Detailed ways

The preparation method of the zinc-doped titanium dioxide nanotube array will be further illustrated below through specific examples.

Example 1:

(1) Polish the pure titanium foil until there is no scratch on the surface, clean it and set aside;

(2) prepare electrolyte: electrolyte is the mixed solution that is the hydrofluoric acid of 40wt% and deionized water preparation by HF content, and the content of HF is 0.3wt% in the electrolyte;

(3) Under 20V DC voltage, with pure titanium foil as the anode and platinum sheet as the cathode, keeping the distance between the two electrodes at 30mm, anodic oxidation is carried out in the electrolyte, and the oxidation time is 4h, and the amorphous titanium dioxide nanotube array is prepared ;

(4) Preparation of zinc-doped titania nanotube arrays: use the titania nanotube arrays prepared above as cathode, platinum sheet as anode, and 0.1mol/L Zn(NO ₃ ) ₂ solution as electrolyte. Electrochemical deposition was carried out under DC voltage for 60 minutes;

(5) Put the electrochemically deposited titanium dioxide nanotube array into a muffle furnace, and anneal at a constant temperature of 450° C. for 2 hours to obtain a zinc-doped titanium dioxide nanotube array.

Example 2:

(1) Polish the pure titanium foil until there is no scratch on the surface, clean it and set aside;

(2) prepare electrolyte: electrolyte is the mixed solution that is the hydrofluoric acid of 40wt% and deionized water preparation by HF content, and the content of HF is 0.5wt% in the electrolyte;

(3) Under 30V DC voltage, using pure titanium foil as the anode and platinum sheet as the cathode, keeping the distance between the two electrodes at 40mm, anodizing in the electrolyte, the oxidation time is 3h, and the amorphous titanium dioxide nanotube array is prepared ;

(4) Preparation of zinc-doped titania nanotube arrays: use the titania nanotube arrays prepared above as cathode, platinum sheet as anode, and 0.2mol/L Zn(NO ₃ ) ₂ solution as electrolyte. Perform electrochemical deposition under DC voltage for 30 minutes;

(5) Put the electrochemically deposited titanium dioxide nanotube array into a muffle furnace, and anneal at a constant temperature of 450° C. for 2 hours to obtain a zinc-doped titanium dioxide nanotube array.

Example 3:

(1) Polish the pure titanium foil until there is no scratch on the surface, clean it and set aside;

(2) prepare electrolyte: electrolyte is the mixed solution that is the hydrofluoric acid of 40wt% and deionized water preparation by HF content, and the content of HF is 0.7wt% in the electrolyte;

(3) Under 40V DC voltage, with pure titanium foil as the anode and platinum sheet as the cathode, keeping the distance between the two electrodes at 50 mm, anodic oxidation is carried out in the electrolyte, and the oxidation time is 2 hours, and the amorphous titanium dioxide nanotube array is prepared ;

(4) Preparation of zinc-doped titania nanotube arrays: use the above-prepared titania nanotube arrays as cathode, platinum sheet as anode, and 0.3mol/L Zn(NO ₃ ) ₂ solution as electrolyte. Electrochemical deposition was carried out under DC voltage for 60 minutes;

(5) Put the electrochemically deposited titanium dioxide nanotube array into a muffle furnace, and anneal at a constant temperature of 600° C. for 2 hours to obtain a zinc-doped titanium dioxide nanotube array.

Example 4:

(1) Polish the pure titanium foil until there is no scratch on the surface, clean it and set aside;

(2) prepare electrolyte: electrolyte is the mixed solution that is the hydrofluoric acid of 40wt% and deionized water preparation by HF content, and the content of HF is 1.0wt% in the electrolyte;

(3) Under 50V DC voltage, with pure titanium foil as anode, platinum sheet as cathode, keep the distance between the two poles as 40mm to carry out anodic oxidation in electrolyte, oxidation time is 2h, make amorphous titania nanotube array;

(4) Preparation of zinc-doped titania nanotube arrays: use the titania nanotube arrays prepared above as cathode, platinum sheet as anode, and 0.5mol/L Zn(NO ₃ ) ₂ solution as electrolyte. Perform electrochemical deposition under DC voltage for 30 minutes;

(5) Put the electrochemically deposited titanium dioxide nanotube array into a muffle furnace, and anneal at a constant temperature of 450° C. for 3 hours to obtain a zinc-doped titanium dioxide nanotube array.

Example 5:

(1) Polish the pure titanium foil until there is no scratch on the surface, clean it and set aside;

(2) prepare electrolyte: electrolyte is the mixed solution that is the hydrofluoric acid of 40wt% and deionized water preparation by HF content, and the content of HF is 0.5wt% in the electrolyte;

(3) Under 20V DC voltage, with pure titanium foil as anode, platinum sheet as cathode, keep the distance between the two poles as 30mm to carry out anodic oxidation in electrolyte, oxidation time is 2h, make amorphous titanium dioxide nanotube array;

(4) Preparation of zinc-doped titania nanotube arrays: use the titania nanotube arrays prepared above as cathode, platinum sheet as anode, and 0.3mol/L Zn(NO ₃ ) ₂ solution as electrolyte. Electrochemical deposition was carried out under DC voltage for 60 minutes;

(5) Put the electrochemically deposited titanium dioxide nanotube array into a muffle furnace, and anneal at a constant temperature of 600° C. for 4 hours to obtain a zinc-doped titanium dioxide nanotube array.

Claims (3)

1. an anonizing prepares the method for zinc doping Nano tube array of titanium dioxide, it is characterized in that following step:

(1) pure titanium foil is polished to surperficial no marking, clean up subsequent use;

(2) preparing electrolyte: electrolytic solution is to be hydrofluoric acid and the formulated mixing solutions of deionized water of 40wt% by HF content, and the content of HF is 0.3wt%-1.0wt% in the electrolytic solution;

(3) under the 10-50V volts DS, be anode with the pure titanium foil, platinized platinum is a negative electrode, and keeping the spacing between the two poles of the earth is 20-50mm, in electrolytic solution, carries out anodic oxidation reactions, and reaction 1-4h makes unformed Nano tube array of titanium dioxide;

(4) preparation of zinc doping Nano tube array of titanium dioxide: the Nano tube array of titanium dioxide with above preparation is done negative electrode, and platinized platinum is an anode, with the Zn (NO of 0.1-0.5mol/L ₃) ₂Solution is electrolytic solution, under the volts DS of 0.3-1.0V, carries out electrochemical deposition 20-60min, Zn ²⁺Under electrical forces and wicking action, enter into the titania nanotube internal layer;

(5) in retort furnace with 450-600 ℃ of cycle annealing 2-4h, promptly get the zinc doping Nano tube array of titanium dioxide.

2. method according to claim 1 is characterized in that described anodic oxidation voltage is 10-50V.

3. method according to claim 1 is characterized in that being 0.3-1.0V with titania nanotube that makes and the exchange of titanium sheet anode and cathode at volts DS, and concentration is the Zn (NO of 0.1-0.5mol/L ₃) ₂Carry out electrochemical deposition in the solution.

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