Preparation method of doped rutile titanium dioxide with selective exposure of {101} and {110} crystal faces and low defect concentration

Abstract

The invention relates to the field of titanium dioxide photocatalytic water decomposition, in particular to a preparation method of doped rutile titanium dioxide with selective exposure of {101} and {110} crystal faces and low defect concentration. The preparation method comprises the following steps: by taking a titanium elementary substance or a titanium-containing compound as a precursor, adding a heterogeneous metal element compound of which the valence state is lower than positive tetravalence as a morphology control agent and a defect inhibitor, fully mixing with an ionic compound serving as a molten salt medium, carrying out one-step high-temperature heat treatment in an oxidizing or reducing atmosphere, cooling, and washing off the molten salt medium, thereby obtaining the titanium-containing composite material. The rutile-doped titanium dioxide nano or micron particles with specific crystal face selective exposure and low defect concentration are obtained. According to the invention, a specific heterogeneously doped metal element compound is used as a morphology regulating agent and a defect inhibitor, so that the synergistic regulation and control of the microstructure and surface and bulk phase defects of rutile titanium dioxide are realized. Therefore, the separation efficiency of rutile titanium dioxide bulk phase photo-generated charges and the activity of photocatalytic decomposition of water to produce hydrogen are greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of titanium dioxide photocatalytic water decomposition, and specifically to a method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, wherein the titanium dioxide is recrystallized by a molten salt heat treatment process, and the surface energy of different crystal planes of the rutile titanium dioxide is regulated by introducing a heterogeneous metal element with a valence lower than that of positive tetravalent titanium, and oxygen vacancies, Ti ions on the surface and in the bulk of the material are inhibited. 3+ And other defects. Background Art

[0002] Rutile titanium dioxide has the characteristics of simple preparation method, low cost, stable structure and band structure that meets the requirements of photocatalytic water decomposition, and is considered to be an ideal photocatalytic material. In order to increase the photogenerated charge separation efficiency of rutile titanium dioxide materials and improve their photocatalytic activity, in recent years, the development of rutile titanium dioxide with specific crystal face exposure has become a research frontier and hotspot in the field and has received widespread attention [Reference 1: Liu G, Yang HG, Pan J, et al. Titanium dioxide crystals with tailored facets [J]. Chemical reviews, 2014, 114 (19): 9559-9612.]. At present, the conventional preparation method for selectively exposing rutile titanium dioxide with specific crystal faces is the hydrothermal method. During the preparation process, anionic morphology control agents such as fluorine elements need to be introduced to reduce the surface energy of the high-energy crystal faces of rutile titanium dioxide, thereby achieving selective exposure of specific crystal faces. However, the reaction temperature of this method is relatively low, resulting in low crystallinity of the obtained rutile titanium dioxide and oxygen vacancies, Ti 3+There are many defects such as MgO2 and TiO2, and the photogenerated charge bulk phase recombination is serious [Reference 2: Li R, Weng Y, Zhou X, et al. Achieving overall water splitting using titanium dioxide-based photocatalysts of different phases [J]. Energy & Environmental Science, 2015, 8 (8): 2377-2382.]. In order to reduce bulk defects, high-temperature solid-phase reaction is a commonly used preparation method. However, due to the harsh reaction conditions and the lack of specific morphology control methods, it is usually difficult to achieve selective exposure of specific crystal planes [Reference 3: Wang J, Liu K, Zhang B, et al. Doping Rh into TiO2 as a visible-light-responsive photocatalyst: The difference between rutile and anatase [J]. Applied Physics Letters, 2021, 119 (21).]. Therefore, it is difficult to achieve coordinated regulation of selective exposure of crystal faces and defect concentration in existing rutile titanium dioxide, resulting in serious recombination of photogenerated charge phases, making it difficult to carry out efficient photocatalytic reactions, and limiting the application of such materials in the field of photocatalysis. Summary of the invention

[0003] The present invention aims to provide a method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, so as to solve the technical problem that it is difficult to simultaneously achieve coordinated regulation of specific crystal plane exposure and defect concentration in existing preparation methods, so as to promote the rapid separation of photogenerated charges in the bulk phase of rutile titanium dioxide material and improve its photocatalytic water decomposition activity.

[0004] The technical solution of the present invention:

[0005] A method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, using titanium or a titanium-containing compound as a precursor, adding a titanium oxide having a valence state lower than that of Ti 4+ A low-valent heterogeneous metal element compound is used as a morphology controller and defect inhibitor, which is fully mixed with an ionic compound as a molten salt medium, and then subjected to a one-step high-temperature heat treatment in an oxidizing or reducing atmosphere. After cooling, the molten salt medium is washed away with deionized water, acid or alkali solution to obtain doped rutile titanium dioxide nano- or micron-particles with selective exposure of {101} and {110} crystal planes and low defect concentration.

[0006] The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, the titanium element is metal titanium powder; the chemical formula of the titanium-containing compound is Ti m X n A compound wherein: X = Cl, Br, I, O, S, N, P, C, Si, B, NO3, SO4, PO4; <m,n≤5。

[0007] The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, the low-valent heterogeneous metal element compound is a compound composed of metal elements with a valence lower than that of positive tetravalent titanium; wherein: the metal element is an alkali metal, alkaline earth metal, IIIA and IIIB group metal elements, and a mixture of one or more of Ce, Pb and Bi, and the amount ratio of the added metal element to the added titanium element is 0.001 to 1.

[0008] The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, the molten salt medium contains one or a mixture of two or more ionic compounds composed of cations and anions; wherein: the cation is Li + , Na + , K + , Rb + , Cs + ,Mg 2+ , Ca 2+ , Sr. 2+ , Ba 2+ , Zn 2+ , Al 3+ , La 3+ , Pb 2+ ,Bi 3+ ; Anion is Cl - Br - , I - , NO3 - , ClO3 - , BrO3 - , IO3 - , NO2 - , SO4 2- ,CO3 2- ,PO4 3- The amount of molten salt medium added is calculated according to the ratio of the amount of metal elements to the amount of titanium element added therein, and the range is 0.001 to 100.

[0009] In the method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, the oxidizing or reducing atmosphere comprises one or a mixed gas of two or more of air, oxygen, nitrogen, argon, ammonia, hydrogen, water vapor, hydrogen sulfide, methane, acetylene, carbon monoxide, carbon dioxide or a vacuum.

[0010] The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration has the following process parameters for the high-temperature heat treatment process: the treatment temperature is 100-1600°C, the treatment time is 0s-240h, and the heating rate and cooling rate are 0.1-50°C / min.

[0011] The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, the acid solution comprises one or a mixed liquid of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, formic acid, acetic acid, and oxalic acid, and the alkali solution comprises one or a mixed liquid of two or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, sodium phosphate, potassium phosphate, rubidium phosphate, and cesium phosphate.

[0012] The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration obtains doped rutile titanium dioxide single crystal particles with {101} and {110} crystal planes, with a particle size of 50nm to 10μm, preferably 100nm to 1μm.

[0013] The design ideas of the present invention are as follows:

[0014] The present invention proposes to use heterogeneous metal doping as a micro-morphology regulator and bulk defect inhibitor to construct doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration. Specifically, in a high-temperature molten salt medium, the target heterogeneous metal element is introduced into the titanium dioxide bulk phase by solid phase diffusion, and the titanium atoms on different crystal planes of rutile are replaced by the heterogeneous element to regulate the surface energy of the crystal plane, effectively reduce the surface energy of the high-energy crystal plane, and achieve selective exposure of specific crystal planes by regulating the type and content of the heterogeneous element; on the other hand, after the heterogeneous element with a valence state lower than positive tetravalent enters the bulk phase of the material, a heterogeneous metal-oxygen vacancy composite pair is formed in the rutile titanium dioxide bulk phase, which effectively inhibits Ti 3+ The generation of ions and the elimination of related defect energy levels formed by charged oxygen vacancies, combining the two strategies is expected to promote the separation of bulk photogenerated charges and develop rutile titanium dioxide photocatalytic materials with efficient charge separation characteristics.

[0015] The present invention uses high-temperature molten salt as a mass transfer medium. In the process of recrystallization treatment of various titanium oxides and their compounds, by introducing heterogeneous metal elements with a valence lower than positive tetravalence, the surface energy of specific crystal faces of rutile titanium dioxide is controllably adjusted under high temperature conditions, and Ti 3+ The generation of ions and the defect energy levels brought about by oxygen vacancies enable the exposure of rutile titanium dioxide crystal faces and the controllable regulation of defect concentration from the surface to the bulk, thereby obtaining rutile titanium dioxide with selective exposure of {101} and {110} crystal faces and low defect concentration, promoting the efficient separation of photogenerated charges and improving its photocatalytic activity.

[0016] Compared with traditional rutile titanium dioxide, the present invention has the following advantages and beneficial effects:

[0017] 1. Highly active surface and high crystallinity: The rutile titanium dioxide prepared by the present invention has {101} and {110} crystal planes exposed, providing a more active surface and a higher crystallinity.

[0018] 2. Fewer defect energy levels: The introduction of low-valent heterogeneous elements effectively inhibits the formation of defect energy levels from the surface to the bulk.

[0019] 3. Stronger photogenerated charge separation ability: The charge separation driving force between {101} and {110} crystal planes works synergistically with the low defect concentration to promote the photogenerated charge separation, thereby improving the photocatalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 .Scanning electron micrograph (SEM) of rutile titanium dioxide without heterogeneous metal doping. The scale bar is indicated in the figure.

[0021] Figure 2 .Scanning electron micrograph (SEM) of scandium-doped rutile titanium dioxide prepared under non-molten salt conditions, with the scale as shown in the figure.

[0022] Figure 3 .Scanning electron micrograph (SEM) of aluminum-doped rutile titanium dioxide prepared under molten salt conditions, with the scale as shown in the figure.

[0023] Figure 4 .X-ray diffraction pattern (XRD) of aluminum-doped rutile titanium dioxide prepared under molten salt conditions.

[0024] Figure 5 .Raman scattering spectrum (Raman) of aluminum-doped rutile titanium dioxide prepared under molten salt conditions.

[0025] Figure 6 .X-ray photoelectron spectroscopy (XPS) of aluminum-doped rutile titanium dioxide prepared under molten salt conditions.

[0026] Figure 7 . UV-Vis absorption spectrum of aluminum-doped rutile titanium dioxide prepared under molten salt conditions.

[0027] Figure 8 . Photocatalytic water splitting activity diagram of aluminum-doped rutile titanium oxide prepared under molten salt conditions.

[0028] Fig. 9 . Scanning electron microscope photograph (SEM) of scandium-doped rutile titanium dioxide prepared under molten salt conditions, with the scale bar as shown in the figure.

[0029] Fig.10 . X-ray photoelectron spectroscopy (XPS) of scandium-doped rutile titanium dioxide prepared under molten salt conditions.

[0030] Fig.11 . Scanning electron microscope photograph (SEM) of gallium-doped rutile titanium dioxide prepared under molten salt conditions, with the scale bar as shown in the figure.

[0031] Fig.12 . X-ray photoelectron spectroscopy (XPS) of gallium-doped rutile titanium dioxide prepared under molten salt conditions. Detailed implementation manners

[0032] In the specific implementation process, the present invention provides a method for preparing rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and a low defect concentration. Using titanium metal or a titanium-containing compound as a precursor, adding a certain amount of a low-valence hetero-metal element compound with a valence lower than +4 (Ti 4+ ) as a morphology control agent and defect inhibitor, after充分 mixing with an ionic compound as a molten salt medium, performing a one-step high-temperature heat treatment in an oxidative or reducing atmosphere, and washing away the molten salt medium with deionized water, an acid solution or an alkali solution after cooling, to obtain doped rutile titanium dioxide nano- or micro-particles with specific crystal plane selective exposure and a low defect concentration. Among them, the specific characteristics are as follows:

[0033] 1. The titanium metal or titanium-containing compound is: titanium metal powder, with the chemical formula Ti m X n (X = Cl, Br, I, O, S, N, P, C, Si, B, NO3, SO4, PO4; 0 < m, n ≤ 5) compounds. The dosage is 1 mg to 1 kg (preferably 0.5 g to 5 g).

[0034] 2. Low-valent heterogeneous metal element compounds (dopants) are compounds containing metal elements with a valence lower than that of tetravalent titanium. The metal elements are alkali metals, alkaline earth metals, IIIA and IIIB metal elements, and a mixture of one or more of Ce, Pb and Bi. The ratio of the amount of the added metal element to the amount of the added titanium element is 0.001 to 1 (preferably 0.01 to 0.2).

[0035] 3. The molten salt medium contains one or a mixture of two or more ionic compounds composed of cations and anions. Among them, the cations include Li + , Na + , K + , Rb + , Cs + ,Mg 2+ , Ca 2+ , Sr. 2+ , Ba 2+ , Zn 2+ , Al 3+ , La 3+ , Pb 2+ ,Bi 3+ One or more than two; anions include Cl - Br - , I - , NO3 - , ClO3 - , BrO3 - , IO3 - , NO2 - , SO4 2- ,CO3 2- ,PO4 3- The amount of the added molten salt is calculated according to the ratio of the amount of the metal element to the amount of the added titanium element, and the range is 0.001 to 100 (preferably 1 to 40).

[0036] 4. Oxidizing or reducing atmospheres include one or a mixture of two or more of air, oxygen, nitrogen, argon, ammonia, hydrogen, water vapor, hydrogen sulfide, methane, acetylene, carbon monoxide, carbon dioxide, and vacuum.

[0037] 5. The process parameters of the high temperature heat treatment process are as follows: treatment temperature is 100-1600°C (preferably 600-1000°C), treatment time is 0s-240h (preferably 1-48h), heating rate and cooling rate are 0.1-50°C / min (preferably 1°C / min-10°C / min).

[0038] 6. The acid used includes one of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, formic acid, acetic acid, oxalic acid, or a mixture of two or more thereof; the alkali used includes one of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, sodium phosphate, potassium phosphate, rubidium phosphate, cesium phosphate, or a mixture of two or more thereof.

[0039] The present invention is described in detail below with reference to embodiments.

[0040] Example 1

[0041] Weigh 7.32g of sodium chloride as the molten salt medium and 1g of rutile titanium dioxide as the precursor without adding any dopant. Grind the two in a mortar for 30 minutes and then heat treat them at 900℃ in a muffle furnace for 2 hours at a heating rate of 10℃ / min. Wash the sample cooled to room temperature with a large amount of deionized water several times until no white precipitate is produced after adding silver nitrate to the upper clear liquid after washing. Collect the white precipitate at the bottom and dry it in an oven at 80℃ for 24 hours.

[0042] The microscopic morphology of the samples prepared in the above examples was observed using a scanning electron microscope, Verios G4 UC. Figure 1 As shown in the figure, without adding dopants, the titanium dioxide nanoparticles obtained after molten salt treatment can only grow and develop to obtain the {110} crystal plane with lower surface energy. The {101} crystal plane with higher surface energy cannot exist stably in the molten salt medium due to the absence of low-valent element doping, which proves the necessity of doping elements in the crystal development process.

[0043] Example 2

[0044] Weigh 1g of rutile titanium dioxide as a precursor, and add 0.034g of scandium trioxide as a dopant. Grind the two in a mortar for 30 minutes, then heat treat at 900℃ in a muffle furnace for 2 hours at a heating rate of 10℃ / min. After cooling to room temperature in the furnace, the target sample can be taken out. In this embodiment, no molten salt medium is added, so no cleaning process is required.

[0045] The microscopic morphology of the samples prepared in the above examples was observed using a scanning electron microscope, Verios G4 UC. Figure 2 As shown in the figure, due to the lack of molten salt medium, it is difficult to incorporate dopants into the bulk phase of rutile titanium dioxide only through solid phase reaction at high temperature. And due to the lack of recrystallization process in molten salt medium, the crystallinity of the grains obtained by high temperature solid phase reaction is also worse than that obtained by molten salt method, so there is no exposure of specific crystal planes.

[0046] Example 3

[0047] Weigh 40g of anhydrous potassium chloride as the molten salt medium, 2g of commercial rutile titanium dioxide as the precursor, and add 0.1g of aluminum oxide as a dopant. Grind the three in a mortar for 30 minutes and then heat treat them at 750℃ in a muffle furnace for 12 hours, with a heating rate of 3℃ / min. The sample cooled to room temperature with the furnace was first washed with hydrochloric acid to clean the aluminum oxide, and then washed with a large amount of deionized water for several times until no white precipitate was produced after adding silver nitrate to the upper clear liquid after cleaning. Collect the white precipitate at the bottom and put it in an oven at 80℃ to dry for 24 hours.

[0048] The microscopic morphology of the samples prepared in the above examples was observed using a scanning electron microscope, Verios G4 UC. Figure 3 As shown in the figure, according to the crystal symmetry of rutile titanium dioxide, the titanium dioxide single crystal obtained after molten salt treatment has developed {101} and {110} crystal planes, and the particle size is about 300nm, indicating that aluminum doping can effectively reduce the crystal plane energy of the {101} crystal plane of rutile titanium dioxide. Compared with the commercial rutile titanium dioxide used as the precursor, the particle size of the sample after molten salt treatment has not increased.

[0049] X-ray diffractometer and Raman spectrometer are used to study the phase and structure of the samples. The equipment model of X-ray diffractometer is D8 Advance, and the equipment model of Raman spectrometer is LabRAM Odyssey. Figure 4-Figure 5 The X-ray diffraction spectrum and Raman spectrum results show that the titanium dioxide product obtained is rutile phase and has high crystallinity. The presence of doping elements is confirmed by X-ray photoelectron spectroscopy, and the equipment model is: ESCALAB 250Xi. Figure 6 The X-ray photoelectron spectroscopy results in the 2000 Å can confirm the presence of the doping element aluminum. Figure 7 From the UV-visible absorption spectrum in FIG, it can be seen that compared with commercial rutile titanium dioxide, the background absorption of the visible light part after 420nm of the rutile titanium dioxide treated by this method is lower. This partial absorption usually comes from the light absorption of the bulk defects of the material, indicating that aluminum doping effectively reduces the bulk defect concentration of the material.

[0050] Example 4

[0051] According to the conditions in Example 3, an experiment was conducted to obtain rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration. After depositing a common co-catalyst for photocatalytic water splitting, the photocatalytic water splitting performance of the sample was studied.

[0052] Photocatalytic water splitting test conditions: 100 mg sample and 100 ml deionized water were added to the reaction solution; the reaction device was a quartz reactor connected to a gas chromatograph; a xenon lamp was used as the reaction light source; the gas chromatograph was an Agilent 7890A, using a capillary column and a TCD thermal conductivity cell detector. Figure 8 As shown, compared with commercial rutile titanium dioxide, the photocatalytic water splitting performance of rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration obtained by this method is improved by dozens of times. This shows that this method increases the driving force for photogenerated charge separation, inhibits the defect recombination of photogenerated charges, and greatly improves the utilization efficiency of photogenerated charges.

[0053] Example 5

[0054] Weigh 26.8g of anhydrous sodium sulfate as the molten salt medium, 0.5g of commercial rutile titanium dioxide as the precursor, and add 0.034g of scandium trioxide as the doping element. Grind the three in a mortar for 30 minutes and then heat treat them at 1000℃ in a muffle furnace for 2 hours at a heating rate of 20℃ / min. Use hydrochloric acid to clean the scandium oxide in the sample cooled to room temperature, and then use a large amount of deionized water to clean it several times until no white precipitate is produced after adding barium chloride to the upper clear liquid after cleaning. Collect the white precipitate at the bottom and put it in an oven at 80℃ to dry for 24 hours.

[0055] like Fig. 9 As shown in the figure, according to the crystal symmetry of rutile titanium dioxide, the titanium oxide single crystal obtained after molten salt treatment has developed {101} and {110} crystal planes, and the particle size is about 5μm, indicating that scandium doping can effectively reduce the crystal plane energy of the {101} crystal plane of rutile titanium oxide. The presence of doping elements was confirmed by X-ray photoelectron spectroscopy, and the equipment model was: ESCALAB 250Xi. Fig.10 The X-ray photoelectron spectroscopy results in the samples can confirm the presence of the doping element scandium.

[0056] Example 6

[0057] Weigh 5.84g of sodium chloride and 9.5g of anhydrous magnesium chloride as eutectic molten salt medium, 0.8g of nano titanium nitride as precursor, and add 0.02g of gallium trioxide as dopant. Grind the three in a mortar for 30 minutes and then heat treat them at 850℃ in a muffle furnace for 48 hours, with a heating rate of 10℃ / min. Wash the sample cooled to room temperature with a large amount of deionized water several times until no white precipitate is produced after adding silver nitrate to the upper clear liquid after washing. Collect the white precipitate at the bottom and put it in an oven at 80℃ for 24 hours.

[0058] like Fig.11As shown in the figure, according to the crystal symmetry of rutile titanium dioxide, the rutile titanium dioxide single crystal particles obtained after molten salt treatment have developed {101} and {110} crystal planes, and the particle size is about 400nm, indicating that gallium doping can effectively reduce the crystal plane energy of the {101} crystal plane of rutile titanium dioxide. The presence of doping elements was confirmed by X-ray photoelectron spectroscopy, and the equipment model was: ESCALAB 250Xi. Fig.12 The X-ray photoelectron spectroscopy results in the sample can confirm the presence of the doping element gallium.

[0059] The implementation results show that the present invention uses a specific heterogeneous doped metal element compound as a morphology regulator and defect inhibitor to achieve coordinated regulation of the microscopic morphology and surface and bulk defects of rutile titanium dioxide. As a result, the separation efficiency of bulk photogenerated charges of rutile titanium dioxide and the photocatalytic decomposition of water to produce hydrogen are greatly improved.

Claims

1. A method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration, characterized in that: Titanium or titanium-containing compounds are used as precursors, and a valence lower than Ti is added. 4+ A low-valent heterogeneous metal element compound is used as a morphology controller and defect inhibitor, which is fully mixed with an ionic compound as a molten salt medium, and then subjected to a one-step high-temperature heat treatment in an oxidizing or reducing atmosphere. After cooling, the molten salt medium is washed away with deionized water, acid or alkali solution to obtain doped rutile titanium dioxide nano- or micron-particles with selective exposure of {101} and {110} crystal planes and low defect concentration.

2. The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration according to claim 1, characterized in that: Titanium is metallic titanium powder; the chemical formula of titanium-containing compounds is Ti m X n Compounds wherein: X = Cl, Br, I, O, S, N, P, C, Si, B, NO3, SO4, PO4; <m,n≤5。 3. The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration according to claim 1, characterized in that: The low-valent heterogeneous metal element compound is a compound containing a metal element with a valence lower than that of positive tetravalent titanium; wherein: the metal element is an alkali metal, an alkaline earth metal, a IIIA and IIIB group metal element, and a mixture of one or more of Ce, Pb and Bi, and the ratio of the amount of the added metal element to the added titanium element is 0.001 to 1.

4. The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration according to claim 1, characterized in that: The molten salt medium contains one or a mixture of two or more ionic compounds composed of cations and anions; wherein: the cation is Li + , Na + , K + , Rb + , Cs + ,Mg 2+ , Ca 2+ , Sr. 2+ , Ba 2+ , Zn 2+ , Al 3+ , La 3+ , Pb 2+ ,Bi 3+ ; Anion is Cl - ,Br - , I - , NO3 - , ClO3 - , BrO3 - , IO3 - , NO2 - , SO4 2- ,CO3 2- ,PO4 3- The amount of molten salt medium added is calculated according to the ratio of the amount of metal elements to the amount of titanium element added therein, and the range is 0.001 to 100.

5. The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration according to claim 1, characterized in that: The oxidizing or reducing atmosphere includes one or a mixture of two or more of air, oxygen, nitrogen, argon, ammonia, hydrogen, water vapor, hydrogen sulfide, methane, acetylene, carbon monoxide, carbon dioxide, or a vacuum.

6. The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration according to claim 1, characterized in that: The process parameters of the high temperature heat treatment process are as follows: the treatment temperature is 100-1600°C, the treatment time is 0s-240h, and the heating rate and cooling rate are 0.1-50°C / min.

7. The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration according to claim 1, characterized in that: The acid solution includes one or a mixed liquid of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, formic acid, acetic acid, and oxalic acid; and the alkali solution includes one or a mixed liquid of two or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, sodium phosphate, potassium phosphate, rubidium phosphate, and cesium phosphate.

8. The method for preparing doped rutile titanium dioxide with selective exposure of {101} and {110} crystal planes and low defect concentration according to claim 1, characterized in that: The method obtains doped rutile titanium dioxide single crystal particles with {101} and {110} crystal planes, and the particle size is 50nm-10μm, preferably 100nm-1μm.

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