CN111155071B

CN111155071B - Sulfur ion injection nano diamond-graphene composite film electrode and preparation method thereof

Info

Publication number: CN111155071B
Application number: CN201911352014.9A
Authority: CN
Inventors: 胡晓君; 蒋梅燕; 陈成克; 李晓
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2019-12-25
Filing date: 2019-12-25
Publication date: 2022-06-21
Anticipated expiration: 2039-12-25
Also published as: CN111155071A

Abstract

The invention provides a sulfur ion implanted nano diamond-graphene composite film, which is prepared by utilizing hot wire chemical vapor deposition on a monocrystalline silicon substrate, carrying out sulfur ion implantation on the prepared composite film, and carrying out vacuum annealing treatment on the implanted composite film to obtain an SNCD-G composite film.

Description

Sulfur ion injection nano diamond-graphene composite film electrode and preparation method thereof

Technical Field

The invention relates to a sulfur ion implanted nano diamond-graphene composite film electrode and a preparation method thereof.

Background

The diamond film is considered as an ideal material of a high-precision electrochemical detection electrode due to the extremely low background current, the wide potential window and the good electrochemical response characteristic. However, the conventionally grown nano-diamond film (NCD) is composed of nano-diamond grains and amorphous carbon grain boundaries, and amorphous carbon or nano-graphite and the like have good electrical characteristics and can effectively promote the electrochemical response of an electrode, so that the electrochemical response current is increased, and the charge transfer rate is reduced. However, the amorphous carbon phase also greatly increases the background current, reduces the potential window and limits the application of the nano-diamond electrode in the field of high-precision electrochemical detection.

We prepared a series of nanodiamond-graphene composite films (NCD-G) and found that the relative relationship of graphene and diamond grains was different, showing distinct electrochemical behavior. When smaller ordered graphene grains appear in the grain boundary, and the (002) direction of the ordered graphene grains is parallel to the edges of adjacent diamond grains, the film has better electrochemical response characteristics; when graphene disappears in the crystal boundary, the TPA wraps the thin film electrode consisting of the nano-diamond, and the electrochemical response characteristic of the thin film electrode is reduced; when the (002) direction of graphene is positioned between adjacent nanodiamond grains in a bridge form, the non-conductive grains and the smaller graphite grains have poor electron exchange capacity with redox probes in solution, and although electrochemical activity is not shown, the background current is reduced, and the potential window is wider. Therefore, if the conductivity of crystal grains in the film can be improved, it is possible to prepare an electrode with good electrochemical response, small background current and wide potential window, and the method is suitable for high-precision trace electrochemical detection. The results of sulfur ion implantation and annealing of the conventional NCD film show that the sulfur ion implantation improves the conductivity of crystal grains, the electrochemical response characteristic of the NCD film subjected to the sulfur ion implantation after annealing at 900 ℃ is greatly improved, however, the background current is still large, the potential window is still narrow, and the NCD film is difficult to be used in the field of high-precision electrochemical detection.

The NCD-G film is different from the traditional NCD film and consists of nano diamond and graphene, and when sulfur ions are injected into the NCD-G film, the influence of the sulfur ions on the electrical and electrochemical properties of the graphene with different forms and position relations in a crystal boundary is not reported in documents. Meanwhile, the research in the literature is that sulfur is covalently grafted to the surface of graphene and is used as an anchoring metal monoatomic atom or a metal nano ion, and the good conductivity of graphene is utilized to improve the electrochemical catalytic property of an anchoring substance, but the reports of the conductivity and the electrochemical activity of sulfur-doped graphene are not found.

Disclosure of Invention

In the invention, the NCD-G film is subjected to sulfur ion injection and annealing treatment at 800-1000 ℃ to prepare the sulfur-injected NCD-G (SNCD-G) film electrode with extremely low background current, a wider potential window and good electrochemical response characteristics.

According to the invention, a hot wire chemical vapor deposition is utilized to prepare the nano-diamond-graphene composite film on a monocrystalline silicon substrate, sulfur ion implantation is carried out on the prepared composite film, and vacuum annealing treatment is carried out on the implanted composite film, thus obtaining the SNCD-G composite film.

The technical scheme of the invention is as follows:

a sulfur ion-implanted nano-diamond-graphene composite film is prepared by the following method:

(1) mixing diamond powder and glycerol (glycerol), uniformly dispersing to obtain diamond powder grinding paste, grinding a monocrystalline silicon wafer by using the obtained diamond powder grinding paste, cleaning and drying the silicon wafer, and finishing a seed crystal process;

the diamond powder is first-grade diamond powder (the grain diameter is 1 micron);

the volume consumption of the glycerol is 50-100 mL/g based on the mass of the diamond powder;

polishing the monocrystalline silicon piece, namely polishing the monocrystalline silicon piece for 30-60 min by taking diamond powder grinding paste on polishing flannelette;

after polishing, sequentially placing the silicon wafer in acetone and ethanol for ultrasonic cleaning, then drying by blowing with nitrogen, completing a seed crystal process, and wrapping with a piece of lens wiping paper for later use;

(2) putting the monocrystalline silicon wafer after the seeding process into hot filament chemical vapor deposition equipment, taking acetone as a carbon source, and carrying the acetone into a reaction chamber by adopting a hydrogen bubbling mode for film growth, wherein the working parameters of the growth process are as follows: the flow ratio of hydrogen to acetone is 200: growing at the growth power of 2000-2400W by 90sccm, controlling the growth pressure to be 1.0-2.6 kPa, and controlling the film growth time to be 40-80 min, and after the growth is finished, slowly reducing the power to 0 at the rate of 0.5-3V/min in a hydrogen atmosphere to complete the preparation of the nano diamond-graphene composite film;

the hot wire chemical vapor deposition equipment is purchased from Shanghai friend-making diamond coating company and has the model number of JUHFCVD 001;

preferably, in the film growth process, the growth pressure is 2.0-2.2 kPa, the growth power is 2000-2200W, and the growth time is 40-60 min;

(3) firstly, carrying out sulfur ion implantation on the nano diamond-graphene composite film, wherein the implantation dosage is 10¹²cm^-2The implantation energy is 55 keV; then carrying out vacuum annealing treatment on the film subjected to sulfur ion implantation at 800-1000 ℃ for 20-30 min to obtain a finished product;

the ion implantation equipment is a 100keV electromagnetic isotope separator which is the Shanghai applied physics research institute of Chinese academy of sciences.

The invention has the beneficial effects that:

1. the NCD-G composite film is subjected to sulfur ion implantation and annealing treatment with a certain dosage, so that the conductivity and electrochemical properties of crystal grains are improved;

2. the obtained sulfur ion implanted nano diamond-graphene composite film (SNCD-G) has excellent electrochemical activity, extremely low background current and wider potential window;

3. compared with the non-injected NCD-G composite film electrode, the electrochemical active area is improved by more than 6 times, and the charge transfer rate is greatly improved;

4. compared with NCD for sulfur ion implantation, the potential window is widened from 2.82V to 3.79V, the peak potential difference of oxidation reduction is reduced from 0.27V to 0.05V, and the electrochemical active area is 640 mu C/cm²Increased to 780 mu C/cm²The background current is significantly reduced;

5. compared with the traditional boron-doped nano diamond electrode, the background current is obviously reduced, the potential window is wider, and the boron-doped nano diamond electrode is very favorable for being applied to the field of high-precision trace detection.

Drawings

FIG. 1 is a Field Emission Scanning Electron Microscope (FESEM) image of an SNCD-G composite film at a growth pressure of 1.3 kPa;

FIG. 2 is a Raman spectrum of an SNCD-G composite film under 1.3 kPa;

FIG. 3 is a high-resolution Transmission Electron Microscope (TEM) image of the SNCD-G composite film at 1.3 kPa;

FIG. 4 is a graph of potential windows and background current for the SNCD-G composite film, NCD-G film, B-NCD film electrode at 1.3 kPa;

FIG. 5 shows the SNCD-G composite film and NCD-G film, B-NCD film at 1mM Fe (CN) under 1.3kPa₆ ^3-/4-And cyclic voltammograms in 1M KCl solution;

FIG. 6 is a Field Emission Scanning Electron Microscope (FESEM) image of the SNCD-G composite film at a growth pressure of 1.6 kPa;

FIG. 7 is a Raman spectrum of an SNCD-G composite membrane at 1.6 kPa;

FIG. 8 is a high-resolution Transmission Electron Microscope (TEM) image of the SNCD-G composite film at 1.6 kPa;

FIG. 9 is a graph of potential windows and background current for the SNCD-G composite film, NCD-G film, B-NCD film electrode at 1.6 kPa;

FIG. 10 shows the SNCD-G composite film and NCD-G film at 1.6kPa, B-NCD film electrode at 1mM Fe (CN)₆ ^3-/4-And cyclic voltammograms in 1M KCl solution;

FIG. 11 is a Field Emission Scanning Electron Microscope (FESEM) image of an SNCD-G composite film at a growth pressure of 2.2 kPa;

FIG. 12 is a Raman spectrum of an SNCD-G composite film at 2.2 kPa;

FIG. 13 is a high-resolution Transmission Electron Microscope (TEM) image of the SNCD-G composite film at 2.2 kPa;

FIG. 14 is a graph of potential window and background current for the SNCD-G composite film, NCD-G film, B-NCD film electrode at 2.2 kPa;

FIG. 15 shows SNCD-G composite films, NCD-G films, B-NCD films at 1mM Fe (CN) under 2.2kPa₆ ^3-/4-And cyclic voltammograms in 1M KCl solution.

Detailed Description

The present invention is further illustrated by the following specific examples, but the scope of the present invention is not limited thereto.

Example 1

Diamond powder (available from shanghai industries grinding tools, abrasives co., ltd., model w1) and glycerol (glycerin) were mixed at a ratio of 1 g: mixing at a ratio of 100ml, stirring uniformly with a glass rod, placing in an ultrasonic cleaner, and ultrasonically dispersing for 5 minutes to fully and uniformly disperse to form diamond powder grinding paste for later use; taking a proper amount of prepared diamond powder grinding paste on polishing flannelette, and grinding the monocrystalline silicon piece for 30 minutes; after polishing, ultrasonically cleaning the treated silicon wafer in acetone and alcohol solution for 5 minutes; and (4) drying the cleaned silicon wafer by using a nitrogen gun, and wrapping the silicon wafer by using a piece of lens wiping paper for later use.

And putting the monocrystalline silicon substrate after the seed crystal is finished into hot filament chemical vapor deposition equipment, taking acetone as a carbon source, and carrying the acetone into the reaction chamber in a hydrogen bubbling mode. Wherein the flow ratio of hydrogen to acetone is 200: 90sccm, the growth power is 2200W, the growth pressure is controlled to be 1.3kPa, and the growth time is 60 min; after the growth is finished, the power is slowly reduced to 0 at the rate of 1V/min in hydrogen atmosphere, and the film preparation process is finished.

Carrying out sulfur ion implantation on the nano diamond-graphene composite film, wherein the implantation dosage is 10¹²cm^-2The implantation energy is 55 keV; then, the film after the sulfur ion implantation is annealed at 900 ℃ for 30min in a vacuum quartz tube.

Observing the composition of the film by adopting a field emission scanning electron microscope and a high-resolution transmission electron microscope; detecting the components of the diamond-graphene composite film by Raman spectroscopy; the electrochemical performance of the sample was measured using an electrochemical workstation.

FIG. 1 is a field emission scanning electron micrograph of the SNCD-G-1.3 sample, which shows that the particles are small in size and are tightly packed into a film.

FIG. 2 is a Raman spectrum, which is seen at 1350cm^-1And 1580cm^-1Are respectively sp²Defect and characteristic peaks of carbon, no diamond peak, indicating that the film is mainly sp²Carbon is the main component.

FIG. 3 is a high resolution transmission electron micrograph of the SNCD-G-1.3 sample, where a large amount of graphene can be observed, indicating that the film is sp-shaped²Carbon is dominant and diamond grains of smaller grain size are present.

Fig. 4 is a graph of potential window and background current before and after sulfur ion implantation. The film exhibits a wider potential window and a lower background current after annealing by sulfur ion implantation than the intrinsic NCD-G-1.3 film and the B-NCD film.

Fig. 5 is a cyclic voltammetry curve before and after S ion implantation, and it can be seen that the electrochemical active area is significantly increased by sulfur ion implantation annealing treatment, indicating that the sulfur ion implantation can significantly improve the electrochemical performance of the NCD-G film. Compared with a B-NCD electrode, although the SNCD-G electrode has a smaller electrochemical active area, the SNCD-G electrode has a large potential window and a small background current, and has application value in the aspect of high-precision trace detection.

Example 2

Diamond powder (available from shanghai industries grinding tools, abrasives co., ltd., model w1) and glycerol (glycerin) were mixed at a ratio of 1 g: mixing 100ml of the mixture, stirring the mixture evenly by using a glass rod, placing the mixture in an ultrasonic cleaner for ultrasonic dispersion for 5 minutes to fully and evenly disperse the mixture to form diamond powder grinding paste, and taking the diamond powder grinding paste for later use; taking a proper amount of prepared diamond powder grinding paste on polishing flannelette, and grinding the monocrystalline silicon piece for 30 minutes; after polishing, ultrasonically cleaning the treated silicon wafer in acetone and alcohol solution for 5 minutes; and (4) drying the cleaned silicon wafer by using a nitrogen gun, and wrapping the silicon wafer by using a piece of lens wiping paper for later use.

And putting the monocrystalline silicon substrate after the seed crystal is finished into hot filament chemical vapor deposition equipment, taking acetone as a carbon source, and carrying the acetone into the reaction chamber in a hydrogen bubbling mode. Wherein the flow ratio of hydrogen to acetone is 200: and (3) 90sccm, the growth power is 2200W, the growth pressure is controlled to be 1.6kPa, the growth time of the film is 60min, and after the growth is finished, the power is slowly reduced to 0 at the rate of 1V/min in a hydrogen atmosphere, so that the film preparation process is completed.

The prepared NCD-G composite film is subjected to sulfur ion implantation with the implantation dose of 10¹²cm^-2The implantation energy is 55 keV; then, the film after the sulfur ion implantation was annealed at 900 ℃ for 30min in a vacuum quartz tube.

FIG. 6 is a field emission scanning electron micrograph of the SNCD-G1.6 sample showing the predominant formation of smaller size grains.

FIG. 7 is a Raman spectrum at 1350cm^-1And 1580cm^-1Is obviously sp appears²The defect peak and the characteristic peak of the carbon and the diamond peak can not be detected, which indicates that the surface layer of the sample is mainly sp²The carbon phase is the main phase.

FIG. 8 is a high resolution TEM image of the SNCD-G1.6 sample, in which the structure of the diamond grains, which are mainly a bridge of the graphene phase, is observed, and few layers of the graphene phase are distributed among the diamond grains.

Fig. 9 is a potential window and background current curve before and after the sulfur ion implantation, and it can be seen that the potential window is wider and the background current is extremely low after the sulfur ion implantation annealing, and is significantly lower than that of the B-NCD thin film electrode, which is reduced by 75.7% compared with the B-NCD thin film electrode, and the potential window is raised by 0.28V.

Fig. 10 is a cyclic voltammetry curve before and after S ion implantation, and it can be seen that the electrochemical active area of the sample after sulfur ion implantation annealing is increased by more than 6 times compared with that of the sample without NCD-G implantation, which indicates that the electrochemical performance of the NCD-G film is effectively improved by sulfur ion implantation. Compared with B-NCD, the electrochemical response area is slightly reduced, but the SNCD-G film has smaller background current which is obviously reduced, and a wider potential window is more favorable for the application of the SNCD-G film in the aspect of high-precision trace detection.

Example 3

And putting the monocrystalline silicon substrate after the seed crystal is finished into hot filament chemical vapor deposition equipment, taking acetone as a carbon source, and carrying the acetone into the reaction chamber by adopting a hydrogen bubbling mode. Wherein the flow ratio of hydrogen to acetone is 200: 90sccm, 2200W of growth power, 2.2kPa of growth pressure and 60min of growth time. After the growth is finished, the power is slowly reduced to 0 at the rate of 1V/min in the hydrogen atmosphere, and the film preparation process is completed.

Carrying out sulfur ion implantation on the nano diamond-graphene composite film, wherein the implantation dosage is 10¹²cm^-2The implantation energy is 55 keV; then to the warpThe film after the sulfur ion implantation was annealed at 900 ℃ for 30min in a vacuum quartz tube.

FIG. 11 is a field emission scanning electron micrograph of the SNCD-G2.2 sample, which is seen to consist primarily of regular close packing of particles, with a grain size of about 500 nm.

FIG. 12 Raman spectrum at 1332cm^-1A diamond characteristic peak appears at 1350cm^-1And 1580cm^-1Sp occurring and disordered²Defect peak and characteristic peak related to carbon indicate that the film is mainly diamond and sp with a certain content²Carbon composition.

FIG. 13 is a high resolution TEM image of the SNCD-G2.2 sample, showing a small amount of the graphene phase distributed between the diamond grains.

Fig. 14 is a potential window and background current curve before and after the sulfur ion implantation, the potential window and background current change is not obvious after the sulfur ion implantation and the annealing treatment, but the potential window and background current have lower background current compared with the B-NCD thin film electrode, which is reduced by 87.8%, and the potential window is widened by 0.26V.

Fig. 15 is a cyclic voltammetry curve before and after S ion implantation, and the electrochemical active area of the sample subjected to sulfur ion implantation and annealing treatment is significantly increased, which shows that the sulfur ion implantation effectively improves the electrochemical performance of the NCD-G film. Compared with B-NCD, although the electrochemical response area is slightly reduced, the SNCD-G film has smaller background current which is obviously reduced, and a wider potential window is more favorable for the application of the SNCD-G film in the aspect of high-precision trace detection.

Claims

1. The sulfur ion implanted nano-diamond-graphene composite film is characterized by being prepared by the following method:

(1) mixing diamond powder and glycerol, uniformly dispersing to obtain diamond powder grinding paste, grinding the monocrystalline silicon wafer by using the obtained diamond powder grinding paste, cleaning and drying the monocrystalline silicon wafer, and finishing a seed crystal process;

(3) firstly, carrying out sulfur ion implantation on the nano diamond-graphene composite film, wherein the implantation dosage is 10¹²cm^-2The implantation energy is 55 keV; and then carrying out vacuum annealing treatment on the film subjected to sulfur ion implantation at 800-1000 ℃ for 20-30 min to obtain a finished product.

2. The sulfur ion-implanted nanodiamond-graphene composite film according to claim 1, wherein in the step (1), the diamond powder is primary diamond powder.

3. The sulfur ion-implanted nanodiamond-graphene composite film according to claim 1, wherein in the step (1), the volume usage amount of the glycerol is 50-100 mL/g based on the mass of the diamond powder.

4. The sulfur ion-implanted nanodiamond-graphene composite film according to claim 1, wherein in the step (1), the polishing of the single crystal silicon wafer is: and (3) taking diamond powder grinding paste on polishing flannelette, and polishing the monocrystalline silicon wafer for 30-60 min.

5. The sulfur ion-implanted nano-diamond-graphene composite film according to claim 1, wherein in the step (1), after polishing, the silicon wafer is sequentially placed in acetone and ethanol for ultrasonic cleaning, and then is dried by blowing with nitrogen gas, so that a seeding process is completed, and the silicon wafer is wrapped with a piece of mirror wiping paper for later use.

6. The sulfur ion-implanted nanodiamond-graphene composite film according to claim 1, wherein in the step (2), the growth pressure is 2.0-2.2 kPa, the growth power is 2000-2200W, and the growth time is 40-60 min in the film growth process.