Preparation method of doped titanium trioxide acid-resistant photoelectric catalytic carrier
By optimizing the preparation process through sol-gel and calcination methods, doped titanium trioxide with small and controllable particle size was prepared, solving the stability and conductivity problems of titanium trioxide in acidic environments and realizing the efficient application of photoelectrophotocatalyst support.
Patent Information
- Application Number
- CN202311482970.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-08
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2043-11-08
AI Technical Summary
Existing technologies make it difficult to prepare titanium trioxide with small and controllable particle size, which limits its application as a photoelectrocatalyst support, and also results in insufficient stability and conductivity in acidic environments.
By combining the sol-gel method with calcination, and by optimizing the composition of the gel precursor and sintering conditions, doped titanium trioxide with small and controllable particle size was prepared. Transition metal doping was then used to improve its conductivity and photoelectric response performance.
The large-scale production of titanium trioxide has been achieved, which has excellent conductivity, stability and photocurrent response performance, and is suitable for photoelectric co-catalytic water splitting to produce hydrogen, reducing energy consumption and cost.
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Figure CN117504844B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of catalytic materials, and particularly relates to a preparation method of a doped titania trioxide acid-resistant photoelectric catalytic carrier. BACKGROUND
[0002] Hydrogen energy has the advantages of high calorific value and cleanness, and is one of the most potential renewable energies. Hydrogen production is an important part of the field of hydrogen energy application, and water splitting is an important way of hydrogen production. Compared with water splitting in alkaline conditions, water splitting in acidic conditions produces hydrogen with higher purity and higher efficiency, so water splitting in acidic conditions is a research direction with great application potential. However, the anode catalyst for water splitting in acidic conditions has poor stability and poor acid resistance, and the catalyst contains a large amount of noble metal, and the energy consumption of pure water splitting is large. The above bottleneck problems hinder the wide application of water splitting in acidic conditions, and the development of non-noble metal catalysts with acid stability and photoelectric catalytic activity or low-noble metal load acid water splitting catalysts is an important solution to the above bottleneck problems.
[0003] The support of the supported catalyst has high requirements. First, the support has a small particle size, which means that it has a larger specific surface area and can load more active substances; second, the support has good electrical conductivity; third, the support itself needs to have good stability; and finally, the good catalyst support itself needs to have certain photoelectric current response performance. The particle size of titanium dioxide is large, and the electrical conductivity and photoelectric current response performance are poor, which seriously limits its application as a photoelectric catalyst carrier.
[0004] Titanium trioxide has an extremely narrow band gap (about 0.09 eV), which endows it with excellent photocatalytic performance and electrical conductivity far superior to that of titanium dioxide. In addition, titanium trioxide has good acid stability and can be used as a good carrier for acid electrolytic water splitting catalysts. Therefore, using titanium trioxide as a catalyst carrier is expected to prepare an acid-resistant, low-cost, high-activity and low-energy photoelectric synergistic catalytic water splitting catalyst.
[0005] However, titanium trioxide is metastable and rare, and is difficult to be stably prepared, not to mention mass production. In addition, the particle size of the titanium trioxide prepared at present is large, and it is difficult to control the particle size, so its application is seriously limited. SUMMARY
[0006] In view of the above defects of the prior art, the technical problem to be solved by the application is how to optimize the preparation process to prepare doped titanium trioxide with small and controllable particle size, excellent electrical conductivity, stability and photoelectric current response, as an acid-resistant photoelectric catalyst carrier.
[0007] To achieve the above object, in a first aspect, the present application provides a preparation method of doped titanium trioxide, comprising:
[0008] S1: gel precursor preparation: after stirring the tetrabutyl titanate, isopropyl alcohol and acetylacetone in a reaction container uniformly, polyethylene glycol (PEG) is added to the system, and the system is heated and stirred at 40-80℃ for 5-30min until it is uniformly dispersed; then, under the condition of heating and stirring, ethylenediamine is added and stirred for 3-20min, and after the sol system is uniformly stirred, the stirring is stopped, and the sol is aged to form a uniformly distributed gel; the gel is vacuum dried to form a dry gel;
[0009] S2: sintering: the dry gel obtained in step S1 is placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the sintering temperature is 950-1200℃, and doped titanium trioxide is prepared.
[0010] In a preferred embodiment, in S1, the volume ratio of tetrabutyl titanate, isopropyl alcohol and acetylacetone is (1-9):(1-4):(1-4).
[0011] In a preferred embodiment, in S1, the volume-to-mass ratio of tetrabutyl titanate, polyethylene glycol and ethylenediamine is (1-9ml):(0.1-1g):(0.5-5ml).
[0012] In a preferred embodiment, in S1, the transition metal (TM) nitrate is added to the reaction container in a ratio of Ti:TM molar ratio = 10:1-20:1 together with tetrabutyl titanate to prepare transition metal-doped titanium trioxide.
[0013] In a preferred embodiment, the transition metal is selected from Co and Ni.
[0014] In a preferred embodiment, in S1, the PEG has a degree of polymerization of 100-1000.
[0015] In a preferred embodiment, in S1, the aging treatment is to place the sol in an environment of 40-80℃ for 0.5-10h.
[0016] In a preferred embodiment, in S1, the gel is vacuum dried for 24-72h.
[0017] In a preferred embodiment, in S2, the hydrogen concentration in the hydrogen-argon mixed gas is 3%-10%.
[0018] In a preferred embodiment, in S2, the sintering time is 0.5-4h.
[0019] In a second aspect, the present application provides the doped titanium trioxide obtained by the above preparation method.
[0020] In a preferred embodiment, the doped titanium trioxide has a particle size of 10-500 nm, preferably 10-100 nm.
[0021] In a third aspect, the present application provides the use of the doped titanium trioxide as an acid-resistant photoelectrocatalyst carrier.
[0022] In a preferred embodiment, the acid-resistant photoelectrocatalyst is used for catalytic hydrogen production by water splitting.
[0023] Technical effects
[0024] The present application can be prepared simply and on a large scale by a sol-gel method combined with a calcination method. By improving the composition and ratio of the sol precursor, the demand for H2 concentration during the sintering process of the doped titanium trioxide can be reduced, the process safety can be improved, and the industrial scale production and application of the doped titanium trioxide can be facilitated.
[0025] By adjusting the ratio of the precursor solute, the sintering time and the sintering temperature, the particle size of the prepared doped titanium trioxide can be controlled, the particle size of the titanium trioxide can be reduced, and the specific surface area can be increased. The prepared doped titanium trioxide has excellent conductivity, stability and photocurrent response performance, which is beneficial to promote its wide application in fields that have special requirements for particle size and specific surface area, such as catalysis.
[0026] In addition, the preparation method of the present application can realize transition metal doping of titanium trioxide. That is, by screening metal salts, doping can be carried out during the preparation of the sol precursor. After sintering, doped titanium trioxide can be obtained. The doping ions (transition metal ions) are successfully doped into the titanium dioxide lattice instead of forming other oxides, which is beneficial to the modification of titanium trioxide and the expansion of its application field.
[0027] The doped titanium trioxide prepared by the present application has controllable and small particle size, good stability, conductivity and photoelectric response, and can be used as a photoelectrocatalyst carrier. It can be effectively used for photocatalytic assisted electrocatalysis for water splitting, which can effectively reduce the cost and energy consumption of hydrogen production by water splitting, and promote the development of the field of photoelectric synergistic catalytic water splitting for hydrogen production. BRIEF DESCRIPTION OF DRAWINGS
[0028] Figure 1 is a TEM image of the doped titanium trioxide prepared by the preferred embodiment of the present application;
[0029] Figure 2 is an XRD spectrum of the doped titanium trioxide prepared by the preferred embodiment of the present application;
[0030] Figure 3The electrochemical stability test results of the doped titanium trioxide prepared by the present application are shown;
[0031] Figure 4 The photoelectric current test results of the doped titanium trioxide prepared by the present application are shown;
[0032] Figure 5 The XRD spectrum of the titanium oxide prepared by the comparative example 1 of the present application is shown;
[0033] Figure 6 The TEM image of the titanium trioxide prepared by the comparative example 2 of the present application is shown. DETAILED DESCRIPTION
[0034] In the detailed description, the present application provides a preparation method of doped titanium trioxide, which comprises:
[0035] S1: gel precursor preparation: after stirring the tetrabutyl titanate, isopropyl alcohol and acetylacetone in a reaction container uniformly, polyethylene glycol PEG is added to the container, and the system is heated and stirred at 40-80℃ for 5-30min until it is uniformly dispersed; then, under the condition of heating and stirring, ethylenediamine is added and stirred for 3-20min, and after the sol system is uniformly stirred, the stirring is stopped, and the sol is aged to form a uniformly distributed gel; the gel is vacuum dried to form a dry gel;
[0036] S2: sintering: the dry gel obtained in step S1 is placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the sintering temperature is 950-1200℃, and the doped titanium trioxide is prepared. In this step, the sintering temperature is greater than 600℃, and the structure-stable titanium dioxide can be obtained, but the particle size of the titanium dioxide is too large, only micron level, which limits its application as a good carrier of catalyst, and the conductivity of the titanium dioxide is only about 10S / cm, which is one of the main factors limiting its photoelectric catalytic performance. The sintering temperature is increased to more than 950℃, and the metastable titanium trioxide is obtained, and its conductivity can reach 160S / cm, which is better than that of titanium dioxide.
[0037] In the preferred embodiment, in S1, the volume ratio of tetrabutyl titanate, isopropyl alcohol and acetylacetone is (1-9):(1-4):(1-4).
[0038] In the preferred embodiment, in S1, the volume-mass ratio of tetrabutyl titanate, polyethylene glycol and ethylenediamine is (1-9ml):(0.1-1g):(0.5-5ml).
[0039] By optimizing the solute ratio of the gel precursor, the control of the particle size of the doped titanium trioxide is facilitated, and the demand for H2 concentration in the sintering process is reduced.
[0040] In a preferred embodiment, in S1, the transition metal (TM) nitrate is added to the reaction vessel together with tetrabutyl titanate in a Ti:TM molar ratio of 10:1-20:1 to prepare the transition metal-doped titanium trioxide.
[0041] In a preferred embodiment, the transition metal is selected from Co, Ni.
[0042] If the amount of transition metal doping is too large, a uniform gel precursor cannot be successfully formed, and uneven precipitation will occur; if other salts are used, such as non-stable valence transition metal nitrates, or some transition metal chlorides, local precipitation will quickly occur, and a gel precursor cannot be formed.
[0043] In a preferred embodiment, in S1, the PEG has a polymerization degree of 100-1000.
[0044] In a preferred embodiment, in S1, the aging treatment is to place the sol in an environment of 40-80°C for aging for 0.5-10h. The purpose of aging is to make the reaction complete and make the Ti ions and PEG relatively fixedly exist in the gel system; if no aging treatment is performed, only a sol can be formed, and unreacted organic matter can exist in the gel system, the system is unstable and difficult to dry, and sintering cannot be performed.
[0045] In a preferred embodiment, in S1, the gel is vacuum dried for 24-72h.
[0046] In a preferred embodiment, in S2, the hydrogen concentration in the hydrogen-argon mixed gas is 3%-10%.
[0047] In a preferred embodiment, in S2, the sintering time is 0.5-4h.
[0048] In a second aspect, the present application provides the doped titanium trioxide obtained by the above preparation method, which has a particle size of 10nm-500nm, preferably 10nm-100nm.
[0049] The following describes a plurality of preferred embodiments of the present application, so that the technical content is clearer and easier to understand. The present application can be embodied in many different forms of embodiments, and the protection scope of the present application is not limited to the embodiments mentioned in the text.
[0050] Example 1
[0051] Preparation of the doped titanium trioxide includes:
[0052] S1: gel precursor preparation: 5 ml of tetrabutyl titanate, 2 ml of isopropyl alcohol, 2 ml of acetylacetone were added to a reaction container and stirred uniformly, 1 g of polyethylene glycol (PEG, degree of polymerization 400), the system was placed in 50°C heating and stirring for 30 min until uniform dispersion; then under the condition of heating and stirring, 1.5 ml of ethylenediamine was added and stirred for 10 min, and the sol system was uniform, then the stirring was stopped, and the sol was placed in a 60°C environment for aging for 3 h to form a uniformly distributed gel; the gel was vacuum dried for 40 h to form a xerogel;
[0053] S2: sintering: the xerogel obtained in step S1 was placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the hydrogen concentration in the hydrogen-argon mixed gas was 5%, the sintering temperature was 1050°C, and the sintering time was 2 h, to obtain a doped titanium trioxide with a particle size of 100 nm.
[0054] The TEM image of the doped titanium trioxide obtained in this example is shown in Figure 1 It can be seen that a smaller particle size is obtained, which is expected to be a good carrier for photoelectric synergistic catalysis; its XRD spectrum is shown in Figure 2 It can be seen that the metastable titanium trioxide structure is successfully prepared.
[0055] Example 2
[0056] The preparation of the doped titanium trioxide includes:
[0057] S1: gel precursor preparation: 5 ml of tetrabutyl titanate, 2 ml of isopropyl alcohol, 2 ml of acetylacetone were added to a reaction container and stirred uniformly, 1 g of polyethylene glycol (PEG, degree of polymerization 400), the system was placed in 50°C heating and stirring for 30 min until uniform dispersion; then under the condition of heating and stirring, 1.5 ml of ethylenediamine was added and stirred for 10 min, and the sol system was uniform, then the stirring was stopped, and the sol was placed in a 60°C environment for aging for 3 h to form a uniformly distributed gel; the gel was vacuum dried for 40 h to form a xerogel;
[0058] S2: sintering: the xerogel obtained in step S1 was placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the hydrogen concentration in the hydrogen-argon mixed gas was 5%, the sintering temperature was 1050°C, and the sintering time was 2 h, to obtain a doped titanium trioxide with a particle size of 100 nm.
[0059] Example 3
[0060] The preparation of the doped titanium trioxide includes:
[0061] S1: gel precursor preparation: 6 ml of tetrabutyl titanate, 3 ml of isopropyl alcohol, 2 ml of acetylacetone were added into a reaction container and stirred uniformly, 0.5 g of polyethylene glycol (PEG, degree of polymerization 400) was added, the system was heated and stirred at 70°C for 10 min until uniformly dispersed; then 1 ml of ethylenediamine was added under the condition of heating and stirring for 20 min, and the sol system was uniformly stirred and stopped; the sol was placed in a 60°C environment for aging for 4 h to form a uniformly distributed gel; the gel was vacuum dried for 72 h to form a xerogel;
[0062] S2: sintering: the xerogel obtained in step S1 was placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the hydrogen concentration in the hydrogen-argon mixed gas was 10%, the sintering temperature was 1050°C, and the sintering time was 1.5 h, to obtain a doped titanium trioxide with a particle size of 90 nm.
[0063] Example 4
[0064] Preparation of Co-doped titanium trioxide, comprising:
[0065] S1: gel precursor preparation: 0.0005 mol of cobalt nitrate, 6 ml of tetrabutyl titanate, 3 ml of isopropyl alcohol, 2 ml of acetylacetone were added into a reaction container and stirred uniformly, 0.5 g of polyethylene glycol (PEG, degree of polymerization 400) was added, the system was heated and stirred at 70°C for 10 min until uniformly dispersed; then 1 ml of ethylenediamine was added under the condition of heating and stirring for 20 min, and the sol system was uniformly stirred and stopped; the sol was placed in a 60°C environment for aging for 4 h to form a uniformly distributed gel; the gel was vacuum dried for 72 h to form a xerogel;
[0066] S2: sintering: the xerogel obtained in step S1 was placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the hydrogen concentration in the hydrogen-argon mixed gas was 10%, the sintering temperature was 1050°C, and the sintering time was 1.5 h, to obtain a Co-doped titanium trioxide with a particle size of 200 nm.
[0067] Co-doping does not affect the structure of titanium trioxide, and has an optimizing effect on its conductivity and other properties.
[0068] Example 5
[0069] Preparation of Ni-doped titanium trioxide, comprising:
[0070] S1: gel precursor preparation: 0.005 mol of nickel nitrate, 6 ml of tetrabutyl titanate, 3 ml of isopropyl alcohol, 2 ml of acetylacetone were added to a reaction container and stirred uniformly, then 0.5 g of polyethylene glycol (PEG, degree of polymerization 400) was added, and the system was heated and stirred at 70°C for 10 min until it was uniformly dispersed; then 1 ml of ethylenediamine was added under heating and stirring for 20 min, and the sol system was uniformly stirred and stopped, and the sol was placed in a 60°C environment for aging for 4 h to form a uniformly distributed gel; the gel was vacuum dried for 72 h to form a xerogel;
[0071] S2: sintering: the xerogel obtained in step S1 was placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the hydrogen concentration in the hydrogen-argon mixed gas was 10%, the sintering temperature was 1050°C, and the sintering time was 1.5 h, to obtain Ni-doped titanium trioxide with a particle size of 200 nm.
[0072] Ni doping does not affect the structure of titanium trioxide and has an optimizing effect on its conductivity and other properties.
[0073] Experimental Example 1
[0074] The electrochemical stability of the doped titanium trioxide prepared in Example 1 was tested.
[0075] The doped titanium trioxide carrier prepared in Example 1 was uniformly dispersed with an organic solvent and a nafion binder, and then coated on the surface of a rotating disc electrode; a three-electrode system was built, and the system voltage was set to 2.0V (RHE) for stability testing.
[0076] The test results are shown in Table 1. Figure 3 As can be seen, the titanium trioxide carrier can be stably operated for more than 100 h under the condition of 2.0V (RHE), proving that titanium trioxide has excellent electrochemical stability and is an excellent and stable electrochemical carrier.
[0077] Experimental Example 2
[0078] The photoelectric current of the doped titanium trioxide prepared in Example 1 was tested.
[0079] The doped titanium trioxide carrier prepared in Example 1 was dispersed with an organic solvent and coated on ITO glass to make an electrode sheet; a three-electrode system was built, and a constant voltage mode was set with a bias voltage of 0.5V; under the constant voltage of 0.5V, the current of the system under sunlight and without sunlight was tested, respectively, to obtain the response of the system to the photoelectric current.
[0080] The test results are shown in Table 2. Figure 4As shown in the figure, it can be seen that the current value of the doped titania carrier system of the application has obvious steps before and after the sunlight, proving that the catalyst carrier has good light response characteristics.
[0081] Comparative Example 1
[0082] The preparation of titanium oxide includes:
[0083] S1: precursor synthesis: dissolve titanium oxysulfide and polyethylene glycol in pure water to form a mixed solution, the concentration of titanium oxysulfide in the mixed solution is 155 g / L, and the concentration of polyethylene glycol is 250 g / L. After stirring the mixed solution at room temperature for 30 min, the mixed system is heated in an oil bath at 65℃ for 6h to form a yellow sol. The yellow sol is dried at 150℃ under normal pressure for 40h to form a gray-black precursor.
[0084] S2: sintering: the gray-black precursor obtained in step 1) is placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the hydrogen concentration in the hydrogen-argon mixed gas is 5%, the sintering temperature is 700℃, and the sintering time is 1.5h. The XRD spectrum of the titanium oxide obtained after sintering is as shown in Figure 5 As shown in the figure, it can be seen that after reducing the sintering temperature, only titanium dioxide phase can be obtained, and the particle size and conductivity and other performance parameters cannot meet the requirements of the supported catalyst carrier.
[0085] Comparative Example 2
[0086] The preparation of doped titania includes:
[0087] S1: gel precursor preparation: 5ml tetrabutyl titanate, 2ml isopropyl alcohol, 2ml acetylacetone are added to the reaction container and stirred uniformly, 1g polyethylene glycol (PEG, degree of polymerization 400) is added, and the system is heated and stirred at 50℃ for 30min until it is uniformly dispersed; then 1.5ml ethylenediamine is added under heating and stirring for 10min, and the sol system is uniformly stirred and then stopped, and the sol is placed in a 60℃ environment for aging for 3h to form a uniformly distributed gel; the gel is vacuum dried for 40h to form a dry gel;
[0088] S2: sintering: the dry gel obtained in step S1 is placed in a tube furnace and sintered in a hydrogen-argon mixed gas atmosphere, wherein the hydrogen concentration in the hydrogen-argon mixed gas is 5%, the sintering temperature is 1300℃, and the sintering time is 5.5h, to obtain doped titania, and the TEM image is as shown in Figure 6 As shown in the figure, it can be seen that when the sintering temperature is too high and the time is too long, the particle size of the doped titania is too large and agglomeration occurs, which limits its application as a photoelectric synergistic catalyst carrier.
[0089] From the above, it can be seen that by adjusting the feeding ratio of the gel precursor, adjusting the PEG polymerization degree, and adjusting the sintering time and temperature, the particle size of titanium trioxide can be controlled. When the sintering time is too long, the temperature is too high, and the PEG polymerization degree is too large, the particle size of titanium trioxide is too large. The smaller the particle size is, the better the dispersion of the catalyst active site is, and the more excellent the performance of the catalyst with the carrier is.
[0090] The preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations without creative labor based on the concept of the present application. Therefore, any technical solutions obtained by logical analysis, reasoning or limited experiments based on the prior art according to the concept of the present application should be within the protection scope defined by the claims.
Claims
1. A method for preparing doped titanium trioxide, the method comprising: S1: gel precursor preparation: adding tetrabutyl titanate, isopropyl alcohol and acetylacetone into a reaction container and stirring until uniform, then adding polyethylene glycol (PEG) into the container, and placing the system in a 40-80℃ heating and stirring environment for 5-30min until uniformly dispersed; then adding ethylenediamine under heating and stirring conditions and stirring for 3-20min, stopping stirring after the sol system is uniform, and performing aging treatment on the sol to form a uniformly distributed gel; vacuum drying the gel to form a xerogel; the volume ratio of tetrabutyl titanate, isopropyl alcohol and acetylacetone is (1-9) : (1-4) : (1-4) ; S2: sintering: placing the xerogel obtained in step S1 in a tube furnace and sintering in a hydrogen-argon mixed gas atmosphere, wherein the sintering temperature is 950-1200℃, to obtain doped titanium trioxide; In S1, the transition metal nitrate is added into the reaction container in a Ti: transition metal molar ratio of 10:1-20:1 together with the tetrabutyl titanate; the transition metal is selected from Co and Ni; In S2, the hydrogen concentration in the hydrogen-argon mixed gas is 3%-10%.
2. The production method according to claim 1, wherein, In S1, the PEG has a polymerization degree of 100-1000.
3. The production method according to claim 1, wherein, In S1, the aging treatment is aging the sol in a 40-80℃ environment for 0.5-10h. 4.Doped titanium trioxide obtained by the method of any one of claims 1-3.
5. The doppable titania trioxide of claim 4, wherein, The doped titanium trioxide has a particle size of 10nm-500nm. 6.Use of the doped titanium trioxide of claim 4 as an acid-resistant photoelectrocatalyst carrier.
Citation Information
Patent Citations
Electrocatalyst carrier and preparation method thereof
CN115261912A