Preparation method of antioxidant based on Al-CQDs and Al-CNSsTechnical Field
The invention relates to the field of antioxidation application, in particular to preparation of an antioxidant based on aluminum doped quantum dots (Al-CQDs) and aluminum doped carbon nano-sheets (Al-CNSs), and belongs to the technical field of carbon materials.
Background
The high-efficiency antioxidant can control the concentration of ROS and remove excessive free radicals. Free radicals refer to molecules, atoms, ions or groups having one or more unpaired electrons in the outer orbitals. Reactive Oxygen Species (ROS) are highly reactive free radicals derived from oxygen molecules and some molecules, including singlet oxygen1 O2 ) Hydrogen peroxide (H)2 O2 ) Superoxide radical (O)2 ·- ) Hydroxyl radical (. OH), nitric Oxide (NO), and the like. The ROS can repair or remove damaged cells and prevent the cells from dying due to oxidative stress. However, excessive ROS accumulation is irreversible to human injury and can cause a series of problems such as cell injury and apoptosis, aging, cancer, and DNA damage.
Carbon quantum dots (Carbon quantum dots, CQDs) are novel zero-dimensional carbon-based materials composed of dispersed spheroidal carbon particles with particle diameters less than 10 nm. Carbon quantum dots are widely studied and applied in the fields of fluorescence sensing, biological imaging and sensing, drug delivery, adsorption water purification and the like due to excellent physicochemical properties, such as excellent fluorescence characteristics, low toxicity, biocompatibility, good water solubility and the like. The carbon nano-sheets (Carbon nanosheets, CNSs) are novel two-dimensional nano-carbon materials, have high specific surface area, excellent conductivity, biocompatibility and innocuity, and are expected to be applied to the fields of biomedical, sensing, energy storage and the like. Since carbon quantum dots and carbon nanoplatelets have excellent hydrogen donating ability, electron transfer ability, fluorescent property, and low toxicity, CQDs and CNSs are studied for use as antioxidants to scavenge free radicals.
The doping of metal atoms can endow CQDs and CNSs with unique electronegativity and has excellent oxidation resistance and oxidation-reduction regulation capability. According to the action mechanism of the antioxidant, the more easily the antioxidant loses electrons, the stronger the ability to scavenge free radicals and the higher the antioxidant activity. The electrochemical method mainly uses a large amount of carbon-based materials as a carbon source and as a working electrode to prepare carbon quantum dots and carbon nanoplatelets. The electrochemical method has the advantages of low material cost, mild condition, simple post-treatment and unique advantages in surface structure analysis and luminescence mechanism research.
MAX is lamellar ternary transition metal carbide or nitride, wherein M is transition group metal element, A is main group element, and is mainly distributed in III and IV main groups, X is C or N element, such as: al, ga, si, etc., and several tens of MAX compounds have been found, commonly Ti3 AlC2 、Ti3 SiC2 And Ti is2 AlC, etc. Thus, the invention uses Ti3 AlC2 And the MAX phase is a carbon source, and electrolytic voltage is regulated and controlled by an electrochemical method, so that the Al-doped carbon quantum dots and the Al-doped carbon nano sheets (Al-CQDs and Al-CNSs) are respectively prepared. The scavenging experiments of the hydroxyl radicals prove that the two materials show good oxidation resistance and have great possibility and research value in the aspect of scavenging the free radicals.
Disclosure of Invention
First, the technical problem to be solved
The doping of metal atoms can improve the semiconductor performance of the carbon quantum dots and the carbon nano-sheets. Accordingly, an object of the present invention is to provide a method for producing a titanium alloy by using the same material3 AlC2 The MAX phase is a carbon source, and the preparation method of two materials, namely aluminum doped carbon quantum dots (Al-CQDs) and aluminum doped carbon nano sheets (Al-CNSs), is realized by regulating and controlling the electrolytic voltage. The method is a simple electrochemical method for preparing the aluminum-doped carbon quantum dots and the aluminum-doped carbon nano sheets, which is simple, short in period and environment-friendly. With Ti3 AlC2 MAX phase is used as carbon source, electrochemical workstation is used for regulating electrolytic voltage, aluminum doped carbon quantum dots (Al-CQDs) and aluminum doped carbon nano sheets (Al-CNSs) are prepared in high concentration alkali liquor, oxidation resistance of the carbon quantum dots and the carbon nano sheets is improved, and the oxidation resistance of the carbon quantum dots and the carbon nano sheets is expanded in the oxidation resistance fieldIs used in the application of (a).
Another object of the present invention is to provide a new design of antioxidant material, i.e. using a simple electrochemical method, using Ti3 AlC2 And the MAX phase is a carbon source, and the oxidation resistance of the prepared Al-CQDs and Al-CNSs is evaluated by regulating and controlling the electrolysis voltage. The prepared metal atom doped carbon nanomaterial, namely the antioxidant is Al-CQDs and Al-CNSs.
(II) technical scheme
The aim of the invention is achieved by the following technical scheme:
a process for preparing the antioxidants based on Al-CQDs and Al-CNSs features that electrochemical working stations are used to apply different electrolytic voltages to Ti at a certain scan rate3 AlC2 Respectively electrolyzing the aluminum-doped carbon quantum dots Al-CQDs and the aluminum-doped carbon nano sheets Al-CNSs in electrolyte solution.
Further, the preparation method of the aluminum-doped carbon quantum dots, namely Al-CQDs, is a two-electrode system potentiostatic method, and comprises the following steps:
(1) With Ti3 AlC2 The tabletting is used as a carbon source, namely a working electrode, the working electrode and a counter electrode are inserted into the electrolyte by an electrochemical method, an electrochemical workstation is used, voltage is applied, the scanning rate is controlled, and the product solution is obtained after a certain time of electrolytic reaction;
(2) And collecting a product solution, filtering and dialyzing impurities by using a filter and a dialysis bag to obtain an aluminum-doped carbon quantum dot solution, wherein the solution has oxidation resistance.
Further, the preparation method of the aluminum-doped carbon nano-sheets, namely Al-CNSs, is a two-electrode system potentiostatic method, and comprises the following steps:
(1) With Ti3 AlC2 The tabletting is used as a carbon source, namely a working electrode, the working electrode and a counter electrode are inserted into the electrolyte by an electrochemical method, an electrochemical workstation is used, voltage is applied, the scanning rate is controlled, and the product solution is obtained after a certain time of electrolytic reaction;
(2) Collecting a product solution, and filtering and separating out impurities by using a filter and a dialysis bag to obtain an aluminum-doped carbon nano-sheet solution; the solution has oxidation resistance.
The application of the aluminum-doped carbon quantum dots and the carbon nano-sheets prepared by the method is characterized in that the aluminum-doped carbon quantum dots and the carbon nano-sheets prepared by the electrochemical method are used as antioxidants for removing hydroxyl radicals; the fluorescence emission spectra of the aluminum-doped carbon quantum dots and the carbon nano sheet solution are respectively tested through an antioxidant activity experiment, so that the aluminum-doped carbon quantum dots and the carbon nano sheet solution are proved to have good oxidation resistance.
Further, in the preparation method of the aluminum-doped quantum dot, the electrolyte in the step (1) is 0.1M NaOH standard solution as the electrolyte, a constant potential method is adopted, the specific scanning rate is 0.08-0.12V/s, and the electrolytic voltages are 3-8V respectively; the adopted filter is a 220nm water system polyethersulfone needle type filter, the dialysis bag is a dialysis bag with molecular retention of 8000-14000Da, and deionized water is used for continuous dialysis for 2-4 days.
Further, in the preparation method of the aluminum-doped carbon nano-sheet, the electrolyte in the step (1) is 0.1M NaOH standard solution as the electrolyte, a constant potential method is adopted, the specific scanning rate is 0.08-0.12V/s, and the electrolysis voltages are 9.5-10.5V respectively; the adopted filter is a 220nm water system polyethersulfone needle type filter, the dialysis bag is a dialysis bag with molecular retention of 8000-14000Da, and deionized water is used for continuous dialysis for 2-4 days.
Further, the hydroxyl radical scavenging experiments of the Al-CQDs and Al-CNSs based antioxidants were: with 2mL of a solution containing 25mM PBS,0.5mM terephthalic acid, 50. Mu.g/mL TiO2 And 50 μg/mL of Al-CQDs or Al-CNSs; after 1h of irradiation with 8W,365nm ultraviolet light, the fluorescence emission spectra of the two solutions were tested.
The method for testing the antioxidant activity (scavenging hydroxyl free radicals) of the two antioxidants prepared by the method comprises the following specific testing steps:
(1) Preparing a buffer solution: PBS phosphate buffer solution is used for protecting the reagent, and the concentration is 25mM PBS;
(2) Preparing a hydroxyl radical solution: 0.5mM terephthalic acid and 50. Mu.g/mL TiO were used2 To generate hydroxyl radicals;
(3) Preparing a test solution system: a2 mL solution system was prepared containing 25mM PBS,0.5mM terephthalic acid, 50. Mu.g/mL TiO2 And 50 μg/mL of Al-CQDs or 50 μg/mL of Al-CNSs;
(4) And (3) light treatment: after 1h of ultraviolet irradiation (8W, 365 nm), the test solutions were tested for fluorescence emission spectra (test end result minus fluorescence generated by Al-CQDs or Al-CNSs themselves.)
Step (1) in the preparation method of the aluminum-doped carbon quantum dot and Ti in step (1) in the preparation method of the aluminum-doped carbon nano sheet3 AlC2 The pressed sheet, i.e. working electrode, is preferably of high purity Ti having a diameter of about 1.5cm and a thickness of about 2mm3 AlC2 Tabletting.
The counter electrodes in the step (1) in the preparation method of the aluminum-doped carbon quantum dots and the step (1) in the preparation method of the aluminum-doped carbon nano sheets are platinum wires and platinum sheets, and preferably are platinum wire counter electrodes.
The electrochemical workstation used in the electrochemical method in the step (1) in the preparation method of the aluminum-doped carbon quantum dots and the step (1) in the preparation method of the aluminum-doped carbon nano-sheets is preferably CHI 660D electrochemical workstation.
The electrochemical method in the step (1) in the preparation method of the aluminum-doped carbon quantum dots and the step (1) in the preparation method of the aluminum-doped carbon nano-sheets is preferably a constant-voltage scanning method.
The electrolyte in the step (1) in the preparation method of the aluminum-doped carbon quantum dots and the step (1) in the preparation method of the aluminum-doped carbon nano-sheets is NaOH or KOH, and preferably 0.1M NaOH standard solution is used as the electrolyte.
The scanning rate in the step (1) in the preparation method of the aluminum-doped carbon quantum dots and the step (1) in the preparation method of the aluminum-doped carbon nano-sheets is 0.08-0.12V/s, preferably 0.1V/s.
The electrolysis voltage in the step (1) in the preparation method of the aluminum-doped carbon quantum dots is 3V-8V, preferably 7.5V.
The electrolysis voltage in the step (1) in the preparation method of the aluminum-doped carbon nano-sheet is 9.5V-10.5V, preferably 10V.
The electrolysis time in the step (1) in the preparation method of the aluminum-doped carbon quantum dots and the step (1) in the preparation method of the aluminum-doped carbon nano sheets is 5.5-6.5 h, preferably 6h reaction time.
The step (2) in the preparation method of the aluminum-doped carbon quantum dots and the step (2) in the preparation method of the aluminum-doped carbon nano sheets are used for filtering impurities, and a filter, preferably a 220nm water system polyethersulfone needle type filter, is used for removing residual partial impurities.
In the step (2) of the preparation method of the aluminum-doped carbon quantum dots and in the step (2) of the preparation method of the aluminum-doped carbon nano sheets, the impurities are separated out by using a dialysis bag, and preferably the dialysis bag with the molecular cut-off amount of 8000-14000 Da.
The treatment time for precipitating impurities in the step (2) in the preparation method of the aluminum-doped carbon quantum dots and the step (2) in the preparation method of the aluminum-doped carbon nano-sheets is preferably 2-4 days, and preferably 3 days of dialysis time.
(III) technical key point of the invention
1. The invention uses layered ternary transition metal carbide or nitride Ti3 AlC2 And preparing the carbon quantum dots and the carbon nano-sheets by selecting the doped aluminum as a carbon source. Compared with the prior commonly used carbon quantum dots and carbon nano sheets, the Al is doped with the carbon quantum dots and carbon nano sheets, and has the characteristics of increasing the combination capability of the carbon quantum dots and the carbon nano sheets with free radicals, the charge transfer capability and the surface reaction activation sites, so that the possibility of improving the antioxidant activity of the quantum dots is improved, and the carbon quantum dots have good effect on the aspect of free radical removal.
2. The effect of preparing the carbon quantum dots and the carbon nano sheets by doping aluminum is better than that of undoped carbon quantum dots and carbon nano sheets. Low cost, simple process and short preparation period.
3. To ensure the purity of the aqueous solutions of Al-CQDs and Al-CNSs, the scavenging effect of free radicals is satisfied, and dialysis must be performed after the electrolytic scanning. The molecular weight cut-off and dialysis time of the dialysis bag are necessary quality assurance.
(IV) beneficial effects
(1) The preparation method disclosed by the invention is simple, short in preparation period, low in cost and environment-friendly, and has certain commercial feasibility;
(2) According to the invention, the Al-CQDs and the Al-CNSs prepared by an electrochemical method have excellent oxidation resistance.
Drawings
FIG. 1 is a TEM image of electrochemically stripped CQDs (a) and CNSs (b);
FIG. 2 is an XRD pattern for CQDs (7.5V) and CNSs (10V);
FIG. 3 is an infrared plot of CQDs (7.5V) and CNSs (10V);
FIG. 4 shows XPS total spectra of CQDs (7.5V) and CNSs (10V);
FIG. 5 is an Al 2p spectrum of CQDs (7.5V);
FIG. 6 is an Al 2p spectrum of CNSs (10V);
FIG. 7 is a PL profile of CQDs (7.5V) and CNSs (10V);
FIG. 8 is a CV plot of GCE, GQDs and Al-CQDs.
Detailed Description
The present invention will be described in further detail with reference to the following specific examples and drawings, but the embodiments of the present invention are not limited thereto.
Example 1
(1) Using Ti of high purity3 AlC2 Pressed sheets (about 1.5cm in diameter and about 2mm in thickness, purchased from Kaien ceramic powder Co.) were used as working electrodes, which were washed with absolute ethanol and deionized water for use.
(2) Platinum wires are used as counter electrodes, and the electrodes are carefully polished and then washed with absolute ethyl alcohol and deionized water for later use.
(3) Preparing an electrolyte solution: a NaOH standard solution at a concentration of 0.1M was prepared as an electrolyte.
(4) The working electrode (Ti3 AlC2 Tabletting) and a counter electrode platinum wire are respectively fixed by an electrode clamp, inserted into NaOH electrolyte solution, a CHI 660D electrochemical workstation is used, the technical parameters are constant potential method, the specific applied electrolysis voltage is 3V,the reaction time was 6h.
(5) After the reaction was completed, the solution was taken out, and the impurity was filtered using a 220nm aqueous polyethersulfone needle filter.
(6) Placing the filtered solution into a dialysis bag with molecular weight cut-off of 8000-14000Da, and continuously dialyzing with deionized water for 3 days to remove residual impurities. The aluminum-doped carbon quantum dot with oxidation resistance can be obtained, the concentration is 50 mug/mL, and the carbon quantum dot is preserved for standby.
(7) Preparing a solution for a hydroxyl radical scavenging experiment: a2 mL solution system was prepared containing 25mM PBS,0.5mM terephthalic acid, 50. Mu.g/mL TiO2 And 50 μg/mL of Al-CQDs.
(8) Scavenging test of hydroxyl radical: after the above solution was subjected to ultraviolet irradiation (8W, 365 nm) for 1 hour, the fluorescence emission spectrum of the solution was measured using a fluorescence photometer to evaluate the antioxidant activity of Al-CQDs, i.e., the scavenging ability of hydroxyl radicals (the final test result minus the fluorescence generated by Al-CQDs themselves.)
Example 2
(1) Using Ti of high purity3 AlC2 Pressed sheets (about 1.5cm in diameter and about 2mm in thickness, purchased from Kaien ceramic powder Co.) were used as working electrodes, which were washed with absolute ethanol and deionized water for use.
(2) Platinum wires are used as counter electrodes, and the electrodes are carefully polished and then washed with absolute ethyl alcohol and deionized water for later use.
(3) Preparing an electrolyte solution: a NaOH standard solution at a concentration of 0.1M was prepared as an electrolyte.
(4) The working electrode (Ti3 AlC2 Sheeting) and a counter electrode platinum wire are respectively fixed by electrode clamps, inserted into NaOH electrolyte solution, and a CHI 660D electrochemical workstation is used, wherein the technical parameters are a potentiostatic method, the specific applied electrolysis voltage is 6V, and the reaction time is 6h.
(5) After the reaction was completed, the solution was taken out, and the impurity was filtered using a 220nm aqueous polyethersulfone needle filter.
(6) Placing the filtered solution into a dialysis bag with molecular weight cut-off of 8000-14000Da, and continuously dialyzing with deionized water for 3 days to remove residual impurities. The aluminum-doped carbon quantum dot with oxidation resistance can be obtained, the concentration is 50 mug/mL, and the carbon quantum dot is preserved for standby.
(7) Preparing a solution for a hydroxyl radical scavenging experiment: a2 mL solution system was prepared containing 25mM PBS,0.5mM terephthalic acid, 50. Mu.g/mL TiO2 And 50 μg/mL of Al-CQDs.
(8) Scavenging test of hydroxyl radical: after the above solution was subjected to ultraviolet irradiation (8W, 365 nm) for 1 hour, the fluorescence emission spectrum of the solution was measured using a fluorescence photometer to evaluate the antioxidant activity of Al-CQDs, i.e., the scavenging ability of hydroxyl radicals (the final test result minus the fluorescence generated by Al-CQDs themselves.)
Example 3
(1) Using Ti of high purity3 AlC2 Pressed sheets (about 1.5cm in diameter and about 2mm in thickness, purchased from Kaien ceramic powder Co.) were used as working electrodes, which were washed with absolute ethanol and deionized water for use.
(2) Platinum wires are used as counter electrodes, and the electrodes are carefully polished and then washed with absolute ethyl alcohol and deionized water for later use.
(3) Preparing an electrolyte solution: a NaOH standard solution at a concentration of 0.1M was prepared as an electrolyte.
(4) The working electrode (Ti3 AlC2 Sheeting) and counter electrode platinum wires are respectively fixed by electrode clamps, inserted into NaOH electrolyte solution, and a CHI 660D electrochemical workstation is used, wherein the technical parameters are constant potential method, the specific applied electrolysis voltage is 7.5V, and the reaction time is 6h.
(5) After the reaction was completed, the solution was taken out, and the impurity was filtered using a 220nm aqueous polyethersulfone needle filter.
(6) Placing the filtered solution into a dialysis bag with molecular weight cut-off of 8000-14000Da, and continuously dialyzing with deionized water for 3 days to remove residual impurities. The aluminum-doped carbon quantum dot with oxidation resistance can be obtained, the concentration is 50 mug/mL, and the carbon quantum dot is preserved for standby.
(7) Preparing a solution for a hydroxyl radical scavenging experiment: a2 mL solution system was prepared containing 25mM PBS,0.5mM terephthalic acid,50 μg/mL TiO2 And 50 μg/mL of Al-CQDs.
(8) Scavenging test of hydroxyl radical: after the above solution was subjected to ultraviolet irradiation (8W, 365 nm) for 1 hour, the fluorescence emission spectrum of the solution was measured using a fluorescence photometer to evaluate the antioxidant activity of Al-CQDs, i.e., the scavenging ability of hydroxyl radicals (the final test result minus the fluorescence generated by Al-CQDs themselves.)
(9) The morphology characterization of the carbon quantum dots is shown in fig. 1 (a). The exfoliated carbon quantum dots were seen at an electrolysis voltage of 7.5V, were small in size, and were not significantly aggregated.
(10) Product structure and composition characterization: (1) XRD: as shown in FIG. 2, the prepared carbon quantum dots do not exhibit typical Ti3 C2 Is not seen with the original Ti3 AlC2 Characteristic peaks of the phases are typical amorphous signals, and the products are confirmed to be amorphous; (2) FT-IR: as shown in figure 3, the prepared carbon quantum dot is 3200-3500 cm-1 Is stretching vibration of-OH at 1667cm-1 Stretching vibration with position C=O between 1260 cm and 1410cm-1 The positions are due to the in-plane bending of-OH, indicating that a large number of oxygen-containing groups are present on the surface of the carbon quantum dots prepared by electrochemical stripping. At 500-725 cm-1 Characteristic peaks with insignificant positions, considered to be caused by stretching vibration of Al-O/Ti-O, indicate electrochemical stripping of Ti3 AlC2 The obtained carbon quantum dots form a certain amount of metal residues, and are aluminum-doped carbon quantum dots (Al-CQDs). (3) XPS: as shown in fig. 4, the carbon quantum dot prepared at 7.5V is composed of three elements of carbon, oxygen and aluminum. On the Al peak at 7.5V (FIG. 5), significant oxide bonding of Al can be seen.
(11) Hydroxyl radical scavenging ability of aluminum-doped carbon quantum dots: tiO under ultraviolet irradiation2 The solution produced OH radicals, and the added terephthalic acid (TPA) captured the OH radicals to form 2-hydroxyterephthalic acid with fluorescent species (emission peak at 430nm under 315nm excitation). As shown in FIG. 7, it was confirmed that the prepared Al-CQDs had good hydroxyl self-reactivity by the intensity change at the specific position of the PL pattern of the Al-CQDs (7.5V)By the radical scavenging ability.
(12) The excellent hydroxyl radical scavenging ability of Al-CQDs can be demonstrated by studying its electron transfer ability. See FIG. 8, which shows CV plots for GCE, GQDs and Al-CQDs. The redox curve measured by cyclic voltammetry shows that the peak value of the current of the exposed GCE electrode is lower than that of the quantum dot coated with graphene and Al-CQDs, so that the quantum dot prepared by the method has excellent charge transmission capability, and the excellent semiconductor performance is shown.
Example 4
(1) Using Ti of high purity3 AlC2 Pressed sheets (about 1.5cm in diameter and about 2mm in thickness, purchased from Kaien ceramic powder Co.) were used as working electrodes, which were washed with absolute ethanol and deionized water for use.
(2) Platinum wires are used as counter electrodes, and the electrodes are carefully polished and then washed with absolute ethyl alcohol and deionized water for later use.
(3) Preparing an electrolyte solution: a NaOH standard solution at a concentration of 0.1M was prepared as an electrolyte.
(4) The working electrode (Ti3 AlC2 Sheeting) and a counter electrode platinum wire are respectively fixed by electrode clamps, inserted into NaOH electrolyte solution, and a CHI 660D electrochemical workstation is used, wherein the technical parameters are a potentiostatic method, the specific applied electrolysis voltage is 10V, and the reaction time is 6h.
(5) After the reaction was completed, the solution was taken out, and the impurity was filtered using a 220nm aqueous polyethersulfone needle filter.
(6) Placing the filtered solution into a dialysis bag with molecular weight cut-off of 8000-14000Da, and continuously dialyzing with deionized water for 3 days to remove residual impurities. The aluminum-doped carbon nano-sheet with oxidation resistance can be obtained and stored for standby.
(7) Preparing a solution for a hydroxyl radical scavenging experiment: a2 mL solution system was prepared containing 25mM PBS,0.5mM terephthalic acid, 50. Mu.g/mL TiO2 And 50. Mu.g/mL of Al-CNSs.
(8) Scavenging test of hydroxyl radical: after the above solution was subjected to ultraviolet irradiation (8W, 365 nm) for 1 hour, the fluorescence emission spectrum of the solution was measured using a fluorescence photometer to evaluate the antioxidant activity of Al-CNSs, i.e., the scavenging ability of hydroxyl radicals (the final test result minus the fluorescence generated by Al-CNSs themselves.)
(9) The morphology characterization of the carbon nanoplatelets is shown in fig. 1 (b). At an electrolysis voltage of 10V, the peeling off was clearly seen to obtain carbon nanoplatelets.
(10) Product structure and composition characterization: (1) XRD: as shown in FIG. 2, the prepared carbon nanoplatelets do not exhibit typical Ti3 C2 Is not seen with the original Ti3 AlC2 Characteristic peaks of the phases are typical amorphous signals, and the products are confirmed to be amorphous; (2) FT-IR: as shown in FIG. 3, the prepared carbon nano-sheet is 3200-3500 cm-1 Is stretching vibration of-OH at 1667cm-1 Stretching vibration with position C=O between 1260 cm and 1410cm-1 The position is due to the in-plane bending of-OH, indicating that a large number of oxygen-containing groups are present on the surface of the carbon nanoplatelets prepared by electrochemical exfoliation. At 500-725 cm-1 Characteristic peaks with insignificant positions, considered to be caused by stretching vibration of Al-O/Ti-O, indicate electrochemical stripping of Ti3 AlC2 The resulting carbon nanoplatelets formed a certain amount of metal residues, which were aluminum-doped carbon nanoplatelets (Al-CNSs). (3) XPS: as shown in FIG. 4, the carbon nanoplatelets prepared at 7.5V are composed of three elements of carbon, oxygen and aluminum. On the 10V Al peak (FIG. 6), significant oxide bonding of Al can be seen.
(11) Hydroxyl radical scavenging ability of aluminum-doped carbon nanoplates: tiO under ultraviolet irradiation2 The solution produced OH radicals, and the added terephthalic acid (TPA) captured the OH radicals to form 2-hydroxyterephthalic acid with fluorescent species (emission peak at 430nm under 315nm excitation). As shown in FIG. 7, it was confirmed that the prepared Al-CNSs had good hydroxyl radical scavenging ability by intensity variation at specific positions of the PL profile of the Al-CNSs (7.5V).
Experimental results show that both the Al-CQSs and the Al-CNSs show obvious antioxidant activity.
The invention includes, but is not limited to, the above embodiments, any equivalent or partial modification made under the principle of the spirit of the invention, shall be considered as being within the scope of the invention.