Titanium dioxide slurry and preparation method of titanium dioxide photo-anode

Abstract

The invention provides a preparation method of titanium dioxide slurry and a preparation method of a titanium dioxide photo-anode, and relates to the technical field of photoelectrochemical sensors, the preparation method of the titanium dioxide slurry comprises the following steps: step 1, stirring a binder, a solvent, an accelerant, a surface additive, a dispersing agent and a defoaming agent which are added under the constant temperature condition of 30-80 DEG C for 0.2-2 hours, a uniformly-fused mixture is obtained; 2, ethyl cellulose is added into the mixing agent, stirring continues to be conducted for 0.2-2 h at the constant temperature of 30-80 DEG C, and a slurry organic phase is obtained; 3, titanium dioxide powder is added into the slurry organic phase, constant-temperature stirring is continuously conducted for 0.5-1 h, and mixed slurry containing titanium dioxide is obtained; and 4, transferring the mixed slurry into a planetary stirrer, stirring for 0.5-4 hours, carrying out primary dispersion to obtain primary dispersed slurry, and grinding the primary dispersed slurry in a three-roller grinder for 2-5 times to obtain the uniformly dispersed titanium dioxide slurry. The adhesion of the titanium dioxide slurry is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of photoelectrochemical biosensors, and in particular to a method for preparing a titanium dioxide slurry and a method for preparing a titanium dioxide photoanode. Background Art

[0002] Photoelectrochemical biosensors are devices that use the photoelectric properties of semiconductor materials to generate light or current to detect the concentration of the analyte in the biochemical reaction related to the current. In the process of detecting the concentration of the analyte, the photoelectrochemical biosensor converts the light signal into an electrical signal, and the whole process is divided into two parts: excitation and detection. Based on this method, it can significantly reduce the interference factors in the actual detection process and reduce the background signal, so it has great advantages in the sensitivity and selectivity of the analysis. In the process of actual application, photoelectrochemical biosensors are widely used in different fields such as environmental monitoring, biomedicine, food safety and industrial production.

[0003] In photoelectrochemical biosensors, the photoanode is a key component, usually made of highly stable, non-toxic, and highly photoactive materials, such as titanium dioxide (TiO2). Currently, titanium dioxide electrodes used in the preparation of photoelectrochemical biosensors are mostly prepared by drop coating in the laboratory, which is not suitable for large-scale production; at the same time, screen printing technology is considered to be a suitable electrode printing technology for large-scale production because it is suitable for printing on substrates of various shapes and sizes and has high repeatability; however, the slurry process used in the preparation of screen-printed electrodes is too complicated, and the adhesion between the slurry and the substrate is poor, which is particularly prominent in aqueous solutions, which seriously affects the stability and accuracy of the sensor, making it difficult to commercialize.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] In view of this, the exemplary embodiments of the present disclosure provide a method for preparing a titanium dioxide slurry and a method for preparing a titanium dioxide photoanode, thereby overcoming the problem of poor adhesion of the slurry due to the limitations and defects of the related art at least to a certain extent.

[0006] According to one aspect of the present disclosure, a method for preparing titanium dioxide slurry is provided, comprising:

[0007] Step 1: Add a binder, a solvent, a promoter, a surfactant, a dispersant and a defoamer into a beaker, and stir the added binder, solvent, promoter, surfactant, dispersant and defoamer at a constant temperature of 30 to 80° C. for 0.2 to 2 hours to obtain a uniformly fused mixture;

[0008] Step 2, adding ethyl cellulose to the mixture, and continuing to stir at a constant temperature of 30 to 80° C. for 0.2 to 2 hours until the ethyl cellulose is completely dissolved, to obtain a slurry organic phase;

[0009] Step 3, adding titanium dioxide powder to the organic phase of the slurry, and continuously stirring at a constant temperature for 0.5 to 1 hour to obtain a mixed slurry including titanium dioxide;

[0010] Step 4: Transfer the mixed slurry including titanium dioxide to a planetary mixer and stir for 0.5 to 4 hours for preliminary dispersion to obtain a preliminary dispersed slurry, and add the preliminary dispersed slurry to a three-roll mill and grind for 2 to 5 times to obtain a uniformly dispersed titanium dioxide slurry.

[0011] In an exemplary embodiment of the present disclosure, in the uniformly dispersed titanium dioxide slurry, the weight percentage of each component is: titanium dioxide powder: 40-85%, ethyl cellulose: 0.1-2%, binder: 3-8%, solvent: 15-35%, promoter: 0-6%, surface additive: 0-2%, dispersant: 0-4%, defoamer: 0-1%.

[0012] In an exemplary embodiment of the present disclosure, the titanium dioxide powder includes at least one of nano titanium dioxide powder, submicron titanium dioxide powder and micron titanium dioxide powder;

[0013] The binder includes at least one of polyurethane resin, epoxy resin and acrylic resin;

[0014] The solvent includes at least one of diethylene glycol butyl ether, diethylene glycol butyl ether acetate, dibasic ester, terpineol, triethanolamine, ethylene glycol ethyl ether acetate and 3-methoxy-3-methylbutyl acetate.

[0015] In an exemplary embodiment of the present disclosure, the accelerator includes at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane;

[0016] The surface additive includes at least one of BYK381, BYK358N and BYK361N.

[0017] In an exemplary embodiment of the present disclosure, the dispersant includes at least one of BYK-111, castor oil, sorbitan trioleate, triolein, and oleylamine.

[0018] In an exemplary embodiment of the present disclosure, the defoaming agent includes at least one of a mineral oil defoaming agent, a polysiloxane defoaming agent, a fatty alcohol defoaming agent and a polyether defoaming agent.

[0019] According to one aspect of the present disclosure, a method for preparing a titanium dioxide photoanode is provided, comprising:

[0020] Step 1: Printing uniformly dispersed titanium dioxide slurry on a conductive substrate through a 300-500 mesh screen plate; wherein the uniformly dispersed titanium dioxide slurry is prepared by any of the above-mentioned methods for preparing titanium dioxide slurry;

[0021] Step 2: placing the conductive substrate printed with titanium dioxide slurry in a muffle furnace for heating and curing to obtain a titanium dioxide photoanode.

[0022] In an exemplary embodiment of the present disclosure, the conductive substrate includes ITO conductive glass and / or FTO conductive glass.

[0023] In an exemplary embodiment of the present disclosure, in the process of placing the conductive substrate printed with titanium dioxide slurry in a muffle furnace for heating and curing, the heating and curing temperature is 300-500° C., and the heating and curing time is 30-120 min.

[0024] In an exemplary embodiment of the present disclosure, the titanium dioxide photoanode is used to prepare a photoelectrochemical biosensor.

[0025] In a method for preparing a titanium dioxide slurry provided in an exemplary embodiment of the present disclosure, on the one hand, a binder, a solvent, a promoter, a surfactant, a dispersant and a defoamer are added to a beaker, and the added binder, solvent, promoter, surfactant, dispersant and defoamer are stirred for 0.2 to 2 hours at a constant temperature of 30 to 80° C. to obtain a uniformly fused mixture; then ethyl cellulose is added to the mixture, and the mixture is stirred for 0.2 to 2 hours at a constant temperature of 30 to 80° C. until the ethyl cellulose is completely dissolved to obtain a slurry organic phase; and then titanium dioxide powder is added to the slurry organic phase, and the constant temperature stirring is continued. 0.5 to 1 hour to obtain a mixed slurry including titanium dioxide; finally, the mixed slurry including titanium dioxide is transferred to a planetary mixer and stirred for 0.5 to 4 hours for preliminary dispersion to obtain a preliminary dispersed slurry, and the preliminary dispersed slurry is added to a three-roll grinder and ground for 2 to 5 times to obtain a uniformly dispersed titanium dioxide slurry; the complexity of the titanium dioxide slurry preparation process is reduced, thereby improving the preparation efficiency of the titanium dioxide slurry; on the other hand, since a binder, a solvent, a promoter, a surface additive, a dispersant and a defoaming agent are added during the preparation of the titanium dioxide slurry, the adhesion of the titanium dioxide slurry is improved.

[0026] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0028] Figure 1 A scanning electron microscope image of 50 nm titanium dioxide powder added in Example 1 according to an exemplary embodiment of the present disclosure is schematically shown.

[0029] Figure 2 A scanning electron microscope image of 200 nm titanium dioxide powder added in Example 2 according to an exemplary embodiment of the present disclosure is schematically shown.

[0030] Figure 3 A scanning electron microscope image of the surface of a titanium dioxide electrode after sintering in Example 3 according to an exemplary embodiment of the present disclosure is schematically shown.

[0031] Figure 4 The element distribution diagram of the surface of the titanium dioxide electrode after sintering in Example 3 according to an exemplary embodiment of the present disclosure is schematically shown.

[0032] Figure 5 The element distribution diagram of the surface of the titanium dioxide electrode after sintering in another embodiment 3 according to the exemplary embodiment of the present disclosure is schematically shown.

[0033] Figure 6 The IT curve diagram of the titanium dioxide photoanode in Example 3 according to the exemplary embodiment of the present disclosure is schematically shown.

[0034] Figure 7 The JV curve diagram of the titanium dioxide photoanode in Example 3 according to the exemplary embodiment of the present disclosure is schematically shown.

[0035] Figure 8 A schematic diagram schematically shows the detection results of dopamine by a sensor prepared based on the titanium dioxide photoanode in Example 3 according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0037] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0038] In response to the problems existing in the related art, the exemplary embodiments of the present disclosure first provide a method for preparing titanium dioxide slurry; at the same time, on this basis, a method for identifying titanium dioxide photoanode is also provided; based on the method provided by the exemplary embodiments of the present disclosure, the process formula of screen-printed titanium dioxide slurry is improved, thereby improving the adhesion between titanium dioxide powder and the ITO glass substrate, thereby effectively improving the stability and photoelectric performance of the titanium dioxide photoanode for photoelectrochemical biosensors.

[0039] In an exemplary embodiment, the method for preparing the titanium dioxide slurry may include the following steps:

[0040] Step S110. Add a binder, a solvent, a promoter, a surface additive, a dispersant and a defoamer into a beaker, and stir the added binder, solvent, promoter, surface additive, dispersant and defoamer at a constant temperature of 30 to 80° C. for 0.2 to 2 hours to obtain a uniformly fused mixture;

[0041] Step S120. Add ethyl cellulose to the mixture, and continue stirring at a constant temperature of 30 to 80° C. for 0.2 to 2 h until the ethyl cellulose is completely dissolved to obtain a slurry organic phase;

[0042] Step S130. Add titanium dioxide powder to the organic phase of the slurry, and continue to stir at a constant temperature for 0.5 to 1 hour to obtain a mixed slurry including titanium dioxide;

[0043] Step S140. Transfer the mixed slurry including titanium dioxide to a planetary mixer and stir for 0.5 to 4 hours for preliminary dispersion to obtain a preliminary dispersed slurry, and add the preliminary dispersed slurry to a three-roll mill and grind for 2 to 5 times to obtain a uniformly dispersed titanium dioxide slurry.

[0044] In the above-mentioned method for preparing titanium dioxide slurry, on the one hand, a binder, a solvent, a promoter, a surfactant, a dispersant and a defoamer are added to a beaker, and the added binder, solvent, promoter, surfactant, dispersant and defoamer are stirred for 0.2 to 2 hours at a constant temperature of 30 to 80° C. to obtain a uniformly fused mixture; then ethyl cellulose is added to the mixture, and the mixture is stirred for 0.2 to 2 hours at a constant temperature of 30 to 80° C. until the ethyl cellulose is completely dissolved to obtain a slurry organic phase; and then titanium dioxide powder is added to the slurry organic phase, and the constant temperature stirring is continued for 0.5 to 1 hour. , obtaining a mixed slurry including titanium dioxide; finally, transferring the mixed slurry including titanium dioxide to a planetary mixer and stirring for 0.5 to 4 hours for preliminary dispersion to obtain a preliminary dispersed slurry, and adding the preliminary dispersed slurry to a three-roll grinder and grinding for 2 to 5 times to obtain a uniformly dispersed titanium dioxide slurry; reducing the complexity of the titanium dioxide slurry preparation process, thereby improving the preparation efficiency of the titanium dioxide slurry; on the other hand, since a binder, a solvent, a promoter, a surface additive, a dispersant and a defoaming agent are added during the preparation of the titanium dioxide slurry, the adhesion of the titanium dioxide slurry is improved.

[0045] Hereinafter, the specific steps involved in the preparation method of titanium dioxide slurry and the various components used will be explained and illustrated in detail.

[0046] In an exemplary embodiment, in the uniformly dispersed titanium dioxide slurry described above, the weight percentage of each component is: titanium dioxide powder: 40-85%, ethyl cellulose: 0.1-2%, binder: 3-8%, solvent: 15-35%, promoter: 0-6%, surface additive: 0-2%, dispersant: 0-4%, defoamer: 0-1%; that is, in the actual process of preparing titanium dioxide slurry, 40-85% titanium dioxide powder, 0.1-2% ethyl cellulose, 3-8% binder, 15-35% solvent, 0-6% promoter, 0-2% surface additive, 0-4% dispersant and 0-1% defoamer can be weighed in sequence. Meanwhile, the titanium dioxide powders described herein include nano titanium dioxide powders, submicron titanium dioxide powders, micron titanium dioxide powders, and the like; and the reason for selecting titanium dioxide powders of different particle sizes is to improve the bending resistance, adhesion, and fatigue resistance of the obtained titanium dioxide slurry.

[0047] Furthermore, the binder described herein may include but is not limited to polyurethane resin, epoxy resin, acrylic resin, etc.; the solvent described herein may include but is not limited to diethylene glycol butyl ether, diethylene glycol butyl ether acetate, dibasic ester, pinene alcohol, triethanolamine, ethylene glycol ethyl ether acetate, and 3-methoxy-3-methylbutyl acetate, etc.; the accelerator described herein may include but is not limited to γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, Oxysilane and γ-aminopropyltriethoxysilane, etc.; the surface additives recorded here may include but are not limited to BYK381, BYK358N and BYK361N, etc.; the dispersants recorded here may include but are not limited to BYK-111, castor oil, sorbitan trioleate, triolein and oleylamine, etc.; the defoamers recorded here may include but are not limited to mineral oil defoamers, polysiloxane defoamers, fatty alcohol defoamers and polyether defoamers, etc.

[0048] Furthermore, the exemplary embodiments of the present disclosure also provide a method for preparing a titanium dioxide photoanode. Specifically, in the method for preparing a titanium dioxide photoanode, it can be achieved in the following manner: first, a uniformly dispersed titanium dioxide slurry is printed on a conductive substrate through a 300-500 mesh screen plate; wherein the uniformly dispersed titanium dioxide slurry is prepared by any of the above-mentioned methods for preparing titanium dioxide slurry; secondly, the conductive substrate printed with the titanium dioxide slurry is placed in a muffle furnace for heating and curing to obtain a titanium dioxide photoanode; wherein the above-mentioned conductive substrate includes ITO conductive glass and / or FTO conductive glass; and, in the process of placing the conductive substrate printed with the titanium dioxide slurry in a muffle furnace for heating and curing, the heating and curing temperature is 300-500°C, and the heating and curing time is 30-120 minutes.

[0049] Moreover, after obtaining the titanium dioxide photoanode, the titanium dioxide photoanode can be used to prepare a photoelectrochemical biosensor; at the same time, the photoelectrochemical biosensor prepared based on the titanium dioxide photoanode has better adhesion performance and photoelectric performance in aqueous solution.

[0050] The specific preparation method of the titanium dioxide photoanode will be further explained and illustrated in combination with specific embodiments. Specifically, the specific preparation method of the titanium dioxide photoanode may include the following steps:

[0051] S1, weigh a certain amount of organic components such as binder, solvent, accelerator, surfactant, dispersant and defoamer respectively, put them into a beaker, and stir them at a constant temperature of 30-80°C for 0.2-2h until they are evenly mixed;

[0052] S2, then add ethyl cellulose and continue stirring at a constant temperature of 30-80°C for 0.2-2h until the ethyl cellulose is completely dissolved to form a slurry organic phase;

[0053] S3, slowly adding a certain amount of titanium dioxide powder into the above organic phase, stirring at a constant temperature for 0.5 to 1 hour, and then transferring to a planetary mixer and stirring for 0.5 to 4 hours for preliminary dispersion;

[0054] S4, adding the above slurry into a three-roll mill and grinding for 2 to 5 times to finally obtain a uniformly dispersed titanium dioxide slurry;

[0055] S5, printing the uniformly dispersed titanium dioxide slurry on a conductive substrate through a 300-500 mesh screen plate, heating and curing, to form a titanium dioxide photoanode.

[0056] The titanium dioxide photoanode obtained based on the above preparation method has at least the following beneficial effects:

[0057] On the one hand, the photoelectric performance of the photoelectrochemical biosensor photoanode prepared from the titanium dioxide slurry obtained in the exemplary embodiment of the present disclosure reaches an excellent level, showing a broad application prospect; on the other hand, after the titanium dioxide slurry obtained in the exemplary embodiment of the present disclosure is sintered into a film by screen printing, it is immersed in an aqueous solution for a long time and has excellent adhesion on the substrate, thereby effectively improving the stability of the photoelectrochemical biosensor and facilitating its industrial application; on the other hand, the preparation method of the titanium dioxide slurry and the titanium dioxide photoanode recorded in the exemplary embodiment of the present disclosure has a simple process, low production cost, and is easy to realize large-scale production, which is of great significance to the commercialization of photoelectrochemical biosensors.

[0058] Hereinafter, the method for preparing the titanium dioxide slurry and the method for preparing the titanium dioxide photoanode described in the exemplary embodiments of the present disclosure will be explained and illustrated in detail in combination with specific exemplary embodiments. Specifically:

[0059] Embodiment 1:

[0060] S1. Weigh 5% of the total weight of the slurry, acrylic resin, 20% of pinene alcohol, 1% of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.2% of BYK 361N, 1.5% of triolein, 0.2% of polysiloxane defoamer and other organic components into a beaker, and stir at a constant temperature of 40°C for 2h until the mixture is evenly mixed;

[0061] S2. Then 0.25% of the total weight of ethyl cellulose was added to the slurry and stirred at a constant temperature of 40 ° C for 2 h until the ethyl cellulose was completely dissolved to form an organic phase of the slurry;

[0062] S3. 71.85% of the total weight of the slurry 50nm titanium dioxide powder was slowly added to the above organic phase, stirred at constant temperature for 1h, and then transferred to a planetary mixer and stirred at 300 rpm for 3h for preliminary dispersion;

[0063] S4. The slurry was added to a three-roll mill and ground 5 times to obtain a uniformly dispersed titanium dioxide slurry;

[0064] S5. The uniformly dispersed titanium dioxide slurry was printed on a conductive substrate through a 300-mesh screen plate, and placed in a muffle furnace at 350° C. for 90 min to obtain a titanium dioxide photoanode.

[0065] Embodiment 2:

[0066] S1. Weigh 4% of the total weight of the slurry, 12.5% ​​of the dibasic ester, 10% of diethylene glycol butyl ether acetate, 4% of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 1.2% of BYK 358N, 0.15% of triolein, 0.5% of polysiloxane defoamer and other organic components into a beaker, and stir at a constant temperature of 60°C for 1 hour until the mixture is evenly mixed;

[0067] S2. Then 0.1% of the total weight of ethyl cellulose was added to the slurry and stirred at a constant temperature of 60 ° C for 1 h until the ethyl cellulose was completely dissolved to form an organic phase of the slurry;

[0068] S3. 67.55% of the total weight of the slurry 200nm titanium dioxide powder was slowly added to the above organic phase, stirred at constant temperature for 1h, and then transferred to a planetary mixer and stirred at 400 rpm for 3h for preliminary dispersion;

[0069] S4. The slurry was added to a three-roll mill and ground four times to obtain a uniformly dispersed titanium dioxide slurry;

[0070] S5. The uniformly dispersed titanium dioxide slurry is printed on a conductive substrate through a 400-mesh screen plate, and placed in a muffle furnace at 450° C. for 60 min to obtain a titanium dioxide photoanode.

[0071] Embodiment 3:

[0072] S1. Weigh 3% of the total weight of the slurry, epoxy resin, 1.5% of acrylic resin, 10% of dibasic ester, 5% of terpineol, 1.5% of γ-aminopropyl triethoxysilane, 0.25% of BYK 358N, 2% of BYK-111, 0.2% of polysiloxane defoamer and other organic components in a beaker, and stir at a constant temperature of 30°C for 2h until the mixture is uniformly mixed;

[0073] S2. Then 1.5% of the total weight of ethyl cellulose was added to the slurry and stirred at a constant temperature of 30 ° C for 2 h until the ethyl cellulose was completely dissolved to form an organic phase of the slurry;

[0074] S3. 75.05% of the total weight of the slurry 200nm titanium dioxide powder was slowly added to the above organic phase, stirred at constant temperature for 2h, and then transferred to a planetary mixer and stirred at 400 rpm for 4h for preliminary dispersion;

[0075] S4. The slurry was added to a three-roll mill and ground three times to obtain a uniformly dispersed titanium dioxide slurry;

[0076] S5. The uniformly dispersed titanium dioxide slurry was printed on a conductive substrate through a 350-mesh screen plate, and placed in a muffle furnace at 500° C. for 60 min to obtain a titanium dioxide photoanode.

[0077] Example 4

[0078] S1. Weigh 3% of the total weight of the slurry, 2% of the acrylic resin, 20% of the dibasic ester, 1.5% of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 0.2% of BYK 381, 1.5% of BYK-111, 0.35% of the polysiloxane defoamer and other organic components, respectively, and place them in a beaker, and stir at a constant temperature of 60° C. for 0.5 h until the mixture is evenly mixed;

[0079] S2. Then 0.75% of the total weight of ethyl cellulose was added to the slurry and stirred at a constant temperature of 60 ° C for 0.5 h until the ethyl cellulose was completely dissolved to form an organic phase of the slurry;

[0080] S3. 21.2% of the total weight of the slurry 200nm titanium dioxide powder and 49.5% of the 50nm titanium dioxide powder were slowly added to the above organic phase, stirred at a constant temperature for 0.5h, and then transferred to a planetary mixer and stirred at 350 rpm for 4h for preliminary dispersion;

[0081] S4. The slurry was added to a three-roll mill and ground 5 times to obtain a uniformly dispersed titanium dioxide slurry;

[0082] S5. The uniformly dispersed titanium dioxide slurry was printed on a conductive substrate through a 350-mesh screen plate, and placed in a muffle furnace at 400° C. for 60 min to obtain a titanium dioxide photoanode.

[0083] Comparative Example 1:

[0084] S1, weigh 2.2g of terpineol and put it in a glass beaker, stir it magnetically at 60℃ for 30min, then add 0.2g of ethyl cellulose and stir until it is dissolved, then add 0.5g of 50nm titanium dioxide powder, and continue stirring for 2h to obtain a uniformly dispersed titanium dioxide slurry;

[0085] S2, screen-printing the obtained titanium dioxide slurry on a clean FTO glass, placing it in a muffle furnace at 500°C for 50 minutes, and then cooling it with the furnace to obtain the titanium dioxide photoanode.

[0086] Further, the morphology of the titanium dioxide powder used in Example 1 and Example 3 can be characterized by referring to Figure 1 as well as Figure 2As shown; wherein the sizes of the titanium dioxide powders used are 50 nm and 200 nm respectively; at the same time, the morphology of the titanium dioxide photoanode after sintering in Example 3 can be referred to Figure 3 At the same time, the morphology of the titanium dioxide film after sintering in Example 3 can be referred to Figure 4 as well as Figure 5 shown by Figure 4 as well as Figure 5 It can be seen that the sintered titanium dioxide film is a uniformly dispersed porous structure, and no other organic matter remains; further, the electrochemical performance test was carried out in a traditional three-electrode electrolytic cell using an electrochemical workstation, the electrolyte was 0.1M phosphate buffer solution (PBS, pH=7.4), the platinum sheet was used as the counter electrode, and Ag / AgCl was used as the reference electrode. All photocurrent measurements used a high-uniformity integrated xenon lamp as the light source at 100mW / cm 2 under the light of Figure 6 as well as Figure 7 The IT performance and JV performance of the titanium dioxide photoanode in Example 3 are demonstrated, and the current under light is as high as 50 μA / cm 2 , indicating that it has excellent photoelectric properties. The sensor of the titanium dioxide photoanode film was used to detect dopamine: 15μL of aptamer probe solution with a concentration of 30nmol / L for detecting dopamine was sprayed on the photoanode film, kept warm in a constant temperature incubator at 37℃, taken out and washed, and non-specific binding sites were blocked with protein-free blocking solution. The dopamine aptamer nucleic acid sequence is: 5′-(SH)-(CH2)6-GGG AAU UCC GCG UGU GCG CCG CGG AAG AGG GAA UAU AGAGGC CAG CAC AUAGUG AGGCCC UCC UCC C-3′. Figure 8 The detection results of dopamine by the biosensor provided in Example 3 show that the detection range of dopamine is 0.1 pg / mL to 1 ng / mL, and the detection limit is 0.034 pg / mL.

[0087] At the same time, based on the adhesion test results of the titanium dioxide slurry obtained in Examples 1 to 4 and Comparative Example 1, specific reference can be made to the following Table 1:

[0088] Table 1 Results of the test on the adhesion of samples using the cross-cut method according to GB / T 9286 standard

[0089] Example Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Adhesion 3B 4B 4B 3B 2B

[0090] Based on the above-described contents, it can be known that the titanium dioxide slurry and photoanode suitable for photoelectrochemical biosensors prepared in the exemplary embodiments of the present disclosure, by regulating the component ratio and preparation process in the slurry, obtain a titanium dioxide slurry that is extremely easy to screen print, and the printed titanium dioxide photoanode has better adhesion on the substrate after sintering to form a film, which effectively improves the stability of the photoelectrochemical biosensor, obtains excellent photoelectric performance, shows a broad application prospect, and is conducive to its industrial application.

[0091] In addition, the above-mentioned figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present disclosure, and are not intended to be limiting. It is easy to understand that the processes shown in the above-mentioned figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.

[0092] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

[0093] It should be understood that the present disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims. The description and embodiments are to be regarded as exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A method for preparing titanium dioxide slurry, characterized in that: include: Step 1: Add a binder, a solvent, a promoter, a surfactant, a dispersant and a defoamer into a beaker, and stir the added binder, solvent, promoter, surfactant, dispersant and defoamer at a constant temperature of 30 to 80° C. for 0.2 to 2 hours to obtain a uniformly fused mixture; Step 2, adding ethyl cellulose to the mixture, and continuing to stir at a constant temperature of 30 to 80° C. for 0.2 to 2 hours until the ethyl cellulose is completely dissolved, to obtain a slurry organic phase; Step 3, adding titanium dioxide powder to the organic phase of the slurry, and continuously stirring at a constant temperature for 0.5 to 1 hour to obtain a mixed slurry including titanium dioxide; Step 4: Transfer the mixed slurry including titanium dioxide to a planetary mixer and stir for 0.5 to 4 hours for preliminary dispersion to obtain a preliminary dispersed slurry, and add the preliminary dispersed slurry to a three-roll mill and grind for 2 to 5 times to obtain a uniformly dispersed titanium dioxide slurry.

2. The method for preparing titanium dioxide slurry according to claim 1, characterized in that: In the uniformly dispersed titanium dioxide slurry, the weight percentage of each component is: titanium dioxide powder: 40-85%, ethyl cellulose: 0.1-2%, binder: 3-8%, solvent: 15-35%, promoter: 0-6%, surface additive: 0-2%, dispersant: 0-4%, defoamer: 0-1%.

3. The method for preparing titanium dioxide slurry according to claim 1, characterized in that: The titanium dioxide powder includes at least one of nano titanium dioxide powder, submicron titanium dioxide powder and micron titanium dioxide powder; The binder includes at least one of polyurethane resin, epoxy resin and acrylic resin; The solvent includes at least one of diethylene glycol butyl ether, diethylene glycol butyl ether acetate, dibasic ester, terpineol, triethanolamine, ethylene glycol ethyl ether acetate and 3-methoxy-3-methylbutyl acetate.

4. The method for preparing titanium dioxide slurry according to claim 1, characterized in that: The accelerator includes at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane; The surface additive includes at least one of BYK 381, BYK 358N and BYK 361N.

5. The method for preparing titanium dioxide slurry according to claim 1, characterized in that: The dispersant includes at least one of BYK-111, castor oil, sorbitan trioleate, triolein and oleylamine.

6. The method for preparing titanium dioxide slurry according to claim 1, characterized in that: The defoaming agent includes at least one of a mineral oil defoaming agent, a polysiloxane defoaming agent, a fatty alcohol defoaming agent and a polyether defoaming agent.

7. A method for preparing a titanium dioxide photoanode, characterized in that: include: Step 1, printing a uniformly dispersed titanium dioxide slurry on a conductive substrate through a 300-500 mesh screen plate; wherein the uniformly dispersed titanium dioxide slurry is prepared by the method for preparing a titanium dioxide slurry according to any one of claims 1 to 6; Step 2: placing the conductive substrate printed with titanium dioxide slurry in a muffle furnace for heating and curing to obtain a titanium dioxide photoanode.

8. The method for preparing a titanium dioxide photoanode according to claim 7, characterized in that: The conductive substrate includes ITO conductive glass and / or FTO conductive glass.

9. The method for preparing a titanium dioxide photoanode according to claim 7, characterized in that: In the process of placing the conductive substrate printed with titanium dioxide slurry in a muffle furnace for heating and curing, the heating and curing temperature is 300-500° C. and the heating and curing time is 30-120 minutes.

10. The method for preparing a titanium dioxide photoanode according to claim 7, characterized in that: The titanium dioxide photoanode is used to prepare a photoelectrochemical biosensor.

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