CN113042079B - Modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof - Google Patents

Modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof Download PDF

Info

Publication number
CN113042079B
CN113042079B CN202110131044.8A CN202110131044A CN113042079B CN 113042079 B CN113042079 B CN 113042079B CN 202110131044 A CN202110131044 A CN 202110131044A CN 113042079 B CN113042079 B CN 113042079B
Authority
CN
China
Prior art keywords
gqds
cds
catalyst
modified
preparation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110131044.8A
Other languages
Chinese (zh)
Other versions
CN113042079A (en
Inventor
左宁
马莹莹
孙梦
张梦竹
李书珍
王磊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Institute of Technology
Original Assignee
Shanghai Institute of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Institute of Technology filed Critical Shanghai Institute of Technology
Priority to CN202110131044.8A priority Critical patent/CN113042079B/en
Publication of CN113042079A publication Critical patent/CN113042079A/en
Application granted granted Critical
Publication of CN113042079B publication Critical patent/CN113042079B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/24—Nitrogen compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/39—Photocatalytic properties
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/40—Organic compounds containing sulfur
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2305/00—Use of specific compounds during water treatment
    • C02F2305/10—Photocatalysts
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/30—Wastewater or sewage treatment systems using renewable energies
    • Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Catalysts (AREA)

Abstract

The invention relates to a modified N, S-GQDs @ CdS nano catalyst and preparation and application thereof. The preparation method specifically comprises the following steps: (a) Dissolving citric acid and thiourea in water, performing ultrasonic dispersion, transferring to a reactor for hydrothermal reaction, and then sequentially cooling, rotary steaming and drying to obtain N, S-GQDs; (b) Dissolving the N, S-GQDs obtained in the step (a) in water, adding cadmium acetate dihydrate, polyvinylpyrrolidone and thioacetamide, mixing, performing ultrasonic dispersion, transferring to a reactor for hydrothermal reaction, and then sequentially cooling, washing and drying to obtain the N, S-GQDs @ CdS. Compared with the prior art, the photocatalyst can expand the light absorption range, is beneficial to hole-electron separation, can improve the catalytic efficiency, and has good degradation capability on methylene blue under the condition of ultraviolet light.

Description

Modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof
Technical Field
The invention belongs to the technical field of photocatalysis, and particularly relates to a modified N, S-GQDs @ CdS nano-catalyst, and preparation and application thereof.
Background
The catalyst was first discovered by the swedish chemist bei elli usa and has been known for over 100 years. The catalyst has various types and has important and wide application in chemical production. WhereinThe photocatalyst was prepared by Fujishima in 1972 by irradiating with TiO under ultraviolet light 2 The discovery of water degradation has brought about the hot tide of semiconductor photocatalyst research, and the photocatalytic elimination and degradation of pollutants is an active research direction at present. The semiconductor photocatalyst is TiO 2 Silver-based semiconductors, tungsten-based semiconductors, znO, cdS, and other semiconductor materials. The photocatalyst mainly utilizes the fact that the energy of the emission of sunlight and ultraviolet light is larger than the energy gap of a semiconductor material, and valence band electrons in the semiconductor are excited to jump to a high-energy conduction band during illumination, so that electrons and holes are left in the valence band, and a part of photogenerated electrons (e) are generated - ) And a cavity (h) + ) The photocatalyst is diffused to the surface of the photocatalyst and finally has oxidation-reduction reaction with electrons or electron acceptors adsorbed on the surface of the photocatalyst, so that a series of chemical reactions initiated by active groups of the photocatalyst are formed, and the photocatalyst has the advantages of proper energy band potential, high chemical stability, no toxicity, no harm, higher photoelectric conversion efficiency, low cost, high activity and the like, so that the photocatalyst becomes an irreplaceable preferred material in chemical production and is mainly applied to the fields of organic synthesis, catalytic chemistry, environmental management, electrochemistry, biochemistry and the like.
However, the conventional photocatalyst is generally a single photocatalyst, and photo-generated electrons and holes generated in the process of illumination are easily self-recombined, so that the number of the photo-generated electrons and holes is reduced, active sites on the surface of the photocatalyst are lost, the photocatalytic efficiency is reduced, and further development of the photocatalyst is hindered. The modified graphene quantum dot integrates quantum confinement, size effect and edge effect, has the advantages of good water solubility, low biotoxicity, excellent chemical inertness, stable fluorescence, easy surface modification performance, excellent luminescence property, adjustable band gap and the like, and has wide application prospect in the fields related to chemical sensing, biological imaging, medical treatment and energy. Therefore, it is imperative to modify the traditional photocatalyst to prepare a high-efficiency photocatalyst, and how to improve the effective active sites by the mutual combination of the modified photocatalyst or multiple photocatalysts, reduce the recombination rate of the photogenerated electrons and holes generated in the illumination process, and improve the photocatalytic efficiency has become a hotspot of research at present.
Disclosure of Invention
The invention aims to provide a modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof.
The purpose of the invention is realized by the following technical scheme:
a modified N, S-GQDs @ CdS nano-catalyst takes CdS as a core, N, S-GQDs are grown on the surface of the CdS nano-catalyst, namely cadmium sulfide is used as the core, the N, S-GQDs are loaded on the surface of the CdS nano-catalyst, the particle size of the N, S-GQDs is 2-7nm, the particle size of the CdS is 700-905nm, and the CdS are connected through a covalent bond, wherein the GQDs represent Graphene quantum dots (Graphene quantum dot), the N, S-GQDs refer to Graphene quantum dots doped by nitrogen elements and sulfur elements, the specific surface area of the spherical CdS is greatly increased, the transmission rate of photo-generated electrons and holes on the surface of the cadmium sulfide is increased during illumination, and the photocatalysis efficiency is favorably increased.
A preparation method of the modified N, S-GQDs @ CdS nano-catalyst specifically comprises the following steps:
(a) Dissolving citric acid and thiourea in water, performing ultrasonic dispersion, transferring to a reactor for hydrothermal reaction, sequentially cooling, performing rotary evaporation and drying to obtain N, S-GQDs, and emitting blue fluorescence at 365 nm;
(b) Dissolving the N, S-GQDs obtained in the step (a) in water, adding cadmium acetate dihydrate, polyvinylpyrrolidone (PVP for short) and thioacetamide, mixing, ultrasonically dispersing, transferring to a reactor for hydrothermal reaction, and then sequentially cooling, washing and drying to obtain the CdS N, S-GQDs @ wherein the polyvinylpyrrolidone has the function of a cross-linking agent, so that the N, S-GQDs can be better loaded on the cadmium sulfide, and the cadmium acetate dihydrate and the thioacetamide react to obtain the CdS.
In the step (a), the molar ratio of citric acid to thiourea is 1.
In the step (a), the power of the ultrasonic wave is 150W, and the time of the ultrasonic wave is 0.1h, so that the reaction raw materials are uniformly dispersed to fully react.
In the step (a), the temperature of the hydrothermal reaction is 160-200 ℃, preferably 180 ℃, and the time is 4-8h, preferably 6h.
In step (b), the mass ratio of N, S-GQDs, cadmium acetate dihydrate, polyvinylpyrrolidone and thioacetamide is (0.02-0.06): 0.266, (0.751-0.1503) and preferably 0.04.
In step (b), cd in cadmium acetate dihydrate 2+ And S in thioacetamide 2- The molar ratio of (1) to (2) is 1.
In step (b), cd in cadmium acetate dihydrate 2+ And S in thioacetamide 2- Preferably 1.
In the step (b), the power of the ultrasonic is 150W, and the time of the ultrasonic is 0.5h, so that the reaction raw materials are uniformly dispersed to fully react.
In the step (b), the temperature of the hydrothermal reaction is 160-200 ℃, preferably 180 ℃, and the time is 6-18h, preferably 12h.
In step (b), cooling to room temperature, washing with anhydrous ethanol, and drying at 60 deg.C overnight
The application of the N, S-GQDs @ CdS nano-catalyst in the aspect of degrading dye wastewater is disclosed. Under the irradiation of ultraviolet light, the degradation effect of N, S-GQDs @ CdS on methylene blue is very excellent.
The invention provides a N, S-GQDs @ CdS nano catalyst, and the performance of the catalyst is regulated and controlled by controlling the reaction time of hydrothermal reaction, the use amount of a precursor N, S-GQDs and the use amount of sodium thioacetamide, so that the N, S-GQDs can be stably loaded on the surface of CdS under a proper condition, and finally the N, S-GQDs @ CdS catalyst is obtained, and the N, S-GQDs in the catalyst can emit blue fluorescence under 365 nm. The introduction of N, S-GQDs into the CdS surface of the carrier can enlarge the light absorption range, is beneficial to the separation of holes and electrons, and can also improve the catalytic efficiency, and has good degradation capability on methylene blue under the ultraviolet condition. Compared with the traditional single N, S-GQDs and CdS, the N, S-GQDs @ CdS nano-catalyst obtained by the method overcomes the problems of instability of the single catalyst, photo-generated electron and hole recombination and self-light defects of the CdS, remarkably improves the catalytic efficiency, and expands the application of the N, S-GQDs @ CdS nano-catalyst in the aspect of photocatalytic degradation of dye wastewater. According to the invention, through selecting other conditions such as used raw materials, temperature and the like, the obtained final product is used for degrading methylene blue pollutants under a certain illumination condition, and the difference of the treatment effects of different catalysts prepared under different material doping conditions on the pollutants is explored, so that more ideas are provided for degrading dye wastewater.
Drawings
FIG. 1 is an infrared spectrum of N, S-GQDs @ CdS nanocatalyst in example 1;
FIG. 2 is a Raman spectrum of the N, S-GQDs @ CdS nanocatalyst of example 1;
FIG. 3 is SEM electron micrograph of N, S-GQDs @ CdS nanocatalyst of example 1;
FIG. 4 is a graph showing the substantial comparison between the non-fluorescence of N, S-GQDs under natural light irradiation and the blue fluorescence under 365nm light irradiation in example 1;
FIG. 5 is a graph of the efficiency of degrading methylene blue by N, S-GQDs @ CdS nanocatalyst in example 2 as a function of time and illumination conditions;
FIG. 6 is a graph showing the efficiency of degrading methylene blue by the N, S-GQDs nanocatalyst in comparative example 1 as a function of time and light conditions;
FIG. 7 is a graph showing the efficiency of CdS nanocatalyst degrading methylene blue in comparative example 2 as a function of time and light conditions.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
The raw materials used in the invention can be purchased in the market, are all analytically pure, do not need further treatment and can be directly used, wherein, the citric acid, the thiourea, the cadmium acetate dihydrate, the polyvinylpyrrolidone and the thioacetamide are all purchased from chemical reagents of national drug group, inc.
Example 1
A modified N, S-GQDs @ CdS nano-catalyst takes CdS as a core, the particle size of N, S-GQDs, N, S-GQDs is 2-7nm, the CdS is spherical, the particle size of the CdS is 700-905nm, and the N, S-GQDs, the S-GQDs and the CdS are connected through covalent bonds. The compound is prepared by the following preparation method, wherein the raw materials comprise citric acid, thiourea, cadmium acetate dihydrate, polyvinylpyrrolidone and thioacetamide, and 0.21g of citric acid, 0.2283g of thiourea, 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone and 0.1127g of thioacetamide are added. The method comprises the following specific steps:
(1) Weighing 0.21g of citric acid and 0.2283g of thiourea, dissolving in 40mL of deionized water, ultrasonically dispersing for 0.1h at 150W, transferring into a 50mL hydrothermal reaction kettle, placing the reaction kettle into a drying oven, preserving heat for 6h at 180 ℃, cooling, rotary evaporating, drying (according to the experimental parameters and experimental operation steps commonly used in laboratories, the same applies below), preparing N, S-GQDs, placing the N, S-GQDs under natural light for irradiation, wherein the compound does not fluoresce, as shown in the left graph in FIG. 4, and placing the N, S-GQDs under 365nm for irradiation, the compound fluoresces blue, as shown in the right graph in FIG. 4;
(2) 20mg of the N, S-GQDs prepared above was placed in a 80mL beaker containing deionized water, to which was added 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone, and 0.1127g of thioacetamide (Cd, cu, in I) 2+ ：S 2- = 1.5), ultrasonically dispersing for 0.5h at the power of 150W, transferring the mixture into a 100mL hydrothermal reaction kettle, preserving the temperature for 12h at 180 ℃, cooling to the room temperature, washing with absolute ethyl alcohol, and drying overnight at 60 ℃ to prepare N, S-GQDs @ CdS. Of the catalystAn infrared spectrogram and a Raman spectrogram are respectively shown in figures 1 and 2, wherein characteristic peaks 1590C = N double bonds and 1200C-C single bonds in the infrared spectrogram indicate that nitrogen elements are successfully doped into the graphene quantum dots, 1590C = S bonds indicate that the nitrogen-doped graphene quantum dots and cadmium sulfide are connected by C = S covalent bonds, and an electron micrograph of the catalyst is shown in figure 3, and the CdS particles are full and are basically spherical, and the particle size of the CdS particles is 789-905nm.
The catalyst is used for catalyzing methylene blue, and specifically comprises the following components: putting 50mgN, S-GQDs @ CdS nano-catalyst into a 150mL quartz tube, adding 10mg/L methylene blue solution into the quartz tube, adding a rotor into the quartz tube, opening a photocatalytic reactor, stirring for 90min under dark conditions to reach adsorption-desorption balance, opening a water circulation system, performing photocatalytic degradation under the condition of a 500w xenon lamp, taking samples every 10min, filtering by using a 0.22 mu m microporous filter head to remove residual catalyst, and measuring absorbance in an ultraviolet spectrophotometer (the same below). The degradation efficiency calculation formula is as follows: eta = A t /A 0 Eta: degradation efficiency; a. The t : absorbance at a certain time: a. The 0 : initial absorbance (same below). The degradation efficiency and the photocatalytic efficiency are shown in table 1, and according to the degradation efficiency of N, S-GQDs @ CdS nano-catalyst to methylene blue under the ultraviolet light condition, the degradation efficiency of the N, S-GQDs @ CdS nano-catalyst to the methylene blue can be known as follows: when the amount of N, S-GQDs is insufficient, the N, S-GQDs loaded on the surface of CdS are insufficient to provide more effective active sites, so that the efficiency of degrading methylene blue is not high.
Example 2
A modified N, S-GQDs @ CdS nano-catalyst takes CdS as a core, the particle size of N, S-GQDs, N, S-GQDs is 2-7nm, the CdS is spherical, the particle size of the CdS is 700-905nm, and the N, S-GQDs, the S-GQDs and the CdS are connected through covalent bonds. The raw materials comprise 0.21g of citric acid, 0.2283g of thiourea, 40mg of N, S-GQDs, 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone and 0.1127g of thioacetamide. The method comprises the following specific steps:
(1) Weighing 0.21g of citric acid and 0.2283g of thiourea, dissolving in 40mL of deionized water, ultrasonically dispersing for 0.1h at 150W, transferring into a 50mL hydrothermal reaction kettle, putting the reaction kettle into a drying box, preserving heat for 6h at 180 ℃, cooling, rotary steaming and drying to prepare N, S-GQDs;
(2) 40mg of the N, S-GQDs prepared above was placed in a 80mL beaker containing deionized water, to which was added 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone, and 0.1127g of thioacetamide (Cd, cu, in I) 2+ ：S 2- = 1.5), ultrasonically dispersing for 0.5h at 150W, transferring the mixture into a 100mL hydrothermal reaction kettle, preserving the temperature for 12h at 180 ℃, cooling to room temperature, washing with absolute ethyl alcohol, and drying overnight at 60 ℃ to prepare N, S-GQDs @ CdS.
When the catalyst is used for catalyzing methylene blue, the degradation efficiency and the photocatalytic efficiency are specifically shown in table 1, the change condition of the degradation efficiency along with time is shown in fig. 5, and the degradation efficiency of the N, S-GQDs @ CdS nano-catalyst to the methylene blue under the ultraviolet light condition can be known as follows: when the N, S-GQDs are proper, the N, S-GQDs loaded on the surface of CdS can provide enough effective active sites, so that the efficiency of degrading methylene blue is the best.
Example 3
A modified N, S-GQDs @ CdS nano-catalyst takes CdS as a core, the particle size of N, S-GQDs, N, S-GQDs is 2-7nm, the CdS is spherical, the particle size of the CdS is 700-905nm, and the N, S-GQDs, the S-GQDs and the CdS are connected through covalent bonds. The compound is prepared by the following preparation method, and the raw materials comprise 0.21g of citric acid, 0.2283g of thiourea, 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone and 0.1127g of thioacetamide. The method comprises the following specific steps:
(1) Weighing 0.21g of citric acid and 0.2283g of thiourea, dissolving in 40mL of deionized water, ultrasonically dispersing for 0.1h at 150W, transferring into a 50mL hydrothermal reaction kettle, putting the reaction kettle into a drying box, preserving heat for 6h at 180 ℃, cooling, rotary steaming and drying to prepare N, S-GQDs;
(2) 60mg of the N, S-GQDs prepared above was placed in a 80mL beaker containing deionized water, to which was added 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone, and 0.1127g of thioacetyl (Cd) 2+ ：S 2- = 1.5), ultrasonically dispersing for 0.5h at 150W, transferring the mixture into a 100mL hydrothermal reaction kettle, and keeping the temperature at 180 DEG CWarming for 12h, cooling to room temperature, washing with absolute ethyl alcohol, and drying at 60 ℃ overnight to prepare N, S-GQDs @ CdS.
When the catalyst is used for catalyzing methylene blue, the degradation efficiency and the photocatalytic efficiency are specifically shown in table 1, and according to the degradation efficiency of the N, S-GQDs @ CdS nano-catalyst to the methylene blue under the ultraviolet light condition, the catalyst has the following characteristics: when the amount of N, S-GQDs is excessive, agglomeration can occur, and the N, S-GQDs loaded on the surface of CdS are not enough to provide more effective active sites, so that the efficiency on the degradation of methylene blue is not high.
Example 4
A modified N, S-GQDs @ CdS nano-catalyst takes CdS as a core, the particle size of N, S-GQDs, N, S-GQDs is 2-7nm, the CdS is spherical, the particle size of the CdS is 700-905nm, and the N, S-GQDs, the S-GQDs and the CdS are connected through covalent bonds. The compound is prepared by the following preparation method, and the raw materials comprise 0.21g of citric acid, 0.2283g of thiourea, 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone and 0.1127g of thioacetamide. The method comprises the following specific steps:
(1) Weighing 0.21g of citric acid and 0.2283g of thiourea, dissolving in 40mL of deionized water, ultrasonically dispersing for 0.1h at 150W, transferring into a 50mL hydrothermal reaction kettle, putting the reaction kettle into a drying box, preserving heat for 6h at 180 ℃, cooling, rotary steaming and drying to prepare N, S-GQDs;
(2) 40mg of the N, S-GQDs prepared above was placed in a 80mL beaker containing deionized water, to which was added 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone, and 0.1127g of thioacetyl (Cd) 2+ ：S 2- = 1.5), ultrasonically dispersing for 0.5h at 150W, transferring the mixture into a 100mL hydrothermal reaction kettle, preserving the temperature for 6h at 180 ℃, cooling to room temperature, washing with absolute ethyl alcohol, and drying overnight at 60 ℃ to prepare N, S-GQDs @ CdS.
When the catalyst is used for catalyzing methylene blue, the degradation efficiency and the photocatalytic efficiency are specifically shown in table 1, and according to the degradation efficiency of the N, S-GQDs @ CdS nano-catalyst to the methylene blue under the ultraviolet light condition, the catalyst has the following characteristics: when the hydrothermal reaction time is insufficient, the anchoring of N, S-GQDs on the surface of the CdS carrier is unstable, and more effective active sites are not sufficiently provided, so that the efficiency of degrading methylene blue is not high.
Example 5
A modified N, S-GQDs @ CdS nano-catalyst takes CdS as a core, the particle size of N, S-GQDs, N, S-GQDs is 2-7nm, the CdS is spherical, the particle size of the CdS is 700-905nm, and the N, S-GQDs, the S-GQDs and the CdS are connected through covalent bonds. The compound is prepared by the following preparation method, and the raw materials comprise 0.21g of citric acid, 0.2283g of thiourea, 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone and 0.1127g of thioacetamide. The method comprises the following specific steps:
(1) Weighing 0.21g of citric acid and 0.2283g of thiourea, dissolving in 40mL of deionized water, ultrasonically dispersing for 0.1h at 150W, transferring into a 50mL hydrothermal reaction kettle, putting the reaction kettle into a drying oven, preserving heat for 6h at 180 ℃, cooling, rotary steaming and drying to prepare N, S-GQDs;
(2) 40mg of the N, S-GQDs prepared above was placed in a 80mL beaker containing deionized water, to which was added 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone, and 0.1127g of thioacetyl (Cd) 2+ ：S 2- = 1.5), ultrasonically dispersing for 0.5h at the power of 150W, transferring the mixture into a 100mL hydrothermal reaction kettle, preserving heat for 18h at 180 ℃, cooling to the room temperature, washing with absolute ethyl alcohol, and drying overnight at 60 ℃ to prepare N, S-GQDs @ CdS.
When the catalyst is used for catalyzing methylene blue, the degradation efficiency and the photocatalytic efficiency are specifically shown in table 1, and the degradation efficiency of the N, S-GQDs @ CdS nano-catalyst to the methylene blue under the ultraviolet light condition can be known as follows: when the hydrothermal reaction time is too long, the N, S-GQDs are agglomerated on the surface of the CdS carrier, and are not enough to provide more effective active sites, so that the efficiency on the degradation of methylene blue is not high.
Example 6
A modified N, S-GQDs @ CdS nano-catalyst takes CdS as a core, the particle size of N, S-GQDs, N, S-GQDs is 2-7nm, the CdS is spherical, the particle size of the CdS is 700-905nm, and the N, S-GQDs, the S-GQDs and the CdS are connected through covalent bonds. The preparation method comprises the following steps of preparing raw materials including 0.21g of citric acid, 0.2283g of thiourea, 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone and 0.0751g of thioacetamide. The method comprises the following specific steps:
(1) Weighing 0.21g of citric acid and 0.2283g of thiourea, dissolving in 40mL of deionized water, ultrasonically dispersing for 0.1h at 150W, transferring into a 50mL hydrothermal reaction kettle, putting the reaction kettle into a drying box, preserving heat for 6h at 180 ℃, cooling, rotary steaming and drying to prepare N, S-GQDs;
(2) 40mg of the N, S-GQDs prepared above was placed in a 80mL beaker containing deionized water, to which was added 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone, 0.0751g of thioacetyl (Cd) in 2+ ：S 2- = 1), ultrasonically dispersing for 0.5h at 150W, transferring the mixture into a 100mL hydrothermal reaction kettle, preserving the temperature for 12h at 180 ℃, cooling to room temperature, washing with absolute ethyl alcohol, and drying overnight at 60 ℃ to prepare N, S-GQDs @ CdS.
When the catalyst is used for catalyzing methylene blue, the degradation efficiency and the photocatalytic efficiency are specifically shown in table 1, and the degradation efficiency of the N, S-GQDs @ CdS nano-catalyst to the methylene blue under the ultraviolet light condition can be known as follows: when Cd 2+ ：S 2- When the ratio is 1, the combination of N, S-GQDs and the CdS carrier is not complete and is not enough to provide more effective active sites, so that the efficiency of methylene blue degradation is not high.
Example 7
A modified N, S-GQDs @ CdS nano-catalyst takes CdS as a core, the particle size of N, S-GQDs, N, S-GQDs is 2-7nm, the CdS is spherical, the particle size of the CdS is 700-905nm, and the N, S-GQDs, the S-GQDs and the CdS are connected through covalent bonds. The preparation method comprises the following steps of preparing raw materials including 0.21g of citric acid, 0.2283g of thiourea, 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone and 0.1503g of thioacetamide. The method comprises the following specific steps:
(1) Weighing 0.21g of citric acid and 0.2283g of thiourea, dissolving in 40mL of deionized water, performing ultrasonic dispersion, transferring the solution into a 50mL hydrothermal reaction kettle, putting the reaction kettle into a drying box, keeping the temperature at 180 ℃ for 6 hours, cooling, performing rotary evaporation, and drying to prepare N, S-GQDs;
(2) 40mg of the N, S-GQDs prepared above was placed in 80mL of a beaker containing deionized water, and 0.266g of cadmium acetate dihydrate, 0.2g of polyvinylpyrrolidone, and 0.1503g of thioethyl acetate were added to the beakerAcyl (Cd) 2+ ：S 2- = 1), performing ultrasonic dispersion, transferring the mixture into a 100mL hydrothermal reaction kettle, preserving heat at 180 ℃ for 12h, cooling to room temperature, washing with absolute ethyl alcohol, and drying at 60 ℃ overnight to prepare N, S-GQDs @ CdS.
When the catalyst is used for catalyzing methylene blue, the degradation efficiency and the photocatalytic efficiency are shown in Table 1, and the degradation efficiency of the N, S-GQDs @ CdS nano-catalyst to the methylene blue under the ultraviolet light condition can be known as follows: when Cd is 2+ ：S 2- When the CdS carrier is aggregated in a state of being not less than 1, the CdS carrier is aggregated, and N, S-GQDs cannot be completely loaded on CdS and cannot provide more effective active sites, so that the efficiency of degrading methylene blue is not high.
TABLE 1 summary of the efficiency of degrading methylene blue of N, S-GQDs nanocatalysts prepared in each example and two comparative examples
Figure GDA0003856505700000091
In summary, when the molar ratio of citric acid to thiourea is 1, N, S-GQDs, cadmium acetate dihydrate, polyvinylpyrrolidone and thioacetamide is 0.04 2+ And S 2- The molar ratio of the N to the S-GQDs @ CdS nano-catalyst is 1.5, when the hydrothermal reaction temperature in the step (2) is 180 ℃ and the reaction time is 12 hours, the prepared N, S-GQDs @ CdS nano-catalyst has the optimal degradation performance, the effect of degrading methylene blue with the concentration of 10mg/L is very excellent, the degradation efficiency can reach 100% after the catalyst is irradiated for 90min under the illumination condition, the degradation efficiency of the catalyst prepared under other conditions is more than 76% under the illumination condition, and the catalyst is basically superior to the catalytic effect of a single N, S-GQDs catalyst and a single CdS catalyst.
Comparative example 1
50mg of N, S-GQDs catalyst (obtained by the preparation step (1) shown in example 2) was placed in a 150mL quartz tube, 10mg/L of methylene blue solution was added to the quartz tube, a rotor was added to the quartz tube, a photocatalytic reactor was opened, and stirred in the dark for 90min to achieve adsorption-desorption equilibrium, at which time a water circulation system was opened to carry out photocatalytic degradation under a 500w xenon lamp, samples were taken every 10min, and filtered with a 0.22 μm microporous filter to remove the residual catalyst, and then absorbance measurement was carried out in an ultraviolet spectrophotometer, specifically as shown in FIG. 6, the degradation efficiency was 19% for 90min in the dark and 63% for 90min under illumination.
Comparative example 2
Taking 50mg of CdS catalyst (the CdS catalyst is obtained by the same operation as the preparation step (2) shown in the example 2 except that N, S-GQDs and polyvinylpyrrolidone are not added), putting the CdS catalyst into a 150mL quartz tube, adding 10mg/L of methylene blue solution into the quartz tube, adding a rotor into the quartz tube, opening a photocatalytic reactor, stirring for 90min under the dark condition to achieve adsorption-desorption balance, opening a water circulation system at the moment, carrying out photocatalytic degradation under the condition of a 500w xenon lamp, taking a sample every 10min, filtering by using a 0.22 mu m microporous filter head to remove residual catalyst, and then measuring absorbance in an ultraviolet spectrophotometer, wherein the 90min degradation efficiency is 23% under the dark condition and the 90min degradation efficiency is 78% under the illumination condition, as shown in FIG. 7.
Example 8
A modified N, S-GQDs @ CdS nano-catalyst is prepared by the following preparation method, except that the hydrothermal temperature in the step (1) is 160 ℃ and the time is 8 hours, the hydrothermal temperature in the step (2) is 160 ℃ and the time is 18 hours, and the rest is the same as the preparation steps of the example 2.
Example 9
A modified N, S-GQDs @ CdS nano-catalyst is prepared by the following preparation method, wherein except that the hydrothermal temperature in the step (1) is 200 ℃ and the hydrothermal time is 4 hours, the hydrothermal temperature in the step (2) is 200 ℃ and the hydrothermal time is 8 hours, the preparation method is the same as that of the preparation method in the example 2.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make modifications and alterations without departing from the scope of the present invention.

Claims (7)

1. The preparation method of the modified N, S-GQDs @ CdS nano catalyst is characterized in that the catalyst takes CdS as a core, N, S-GQDs grow on the surface of the CdS as well as are connected with each other through a covalent bond, the N, S-GQDs are graphene quantum dots doped with nitrogen elements and sulfur elements, the catalyst is used for catalyzing and degrading methylene blue, and the preparation method specifically comprises the following steps:
(a) Dissolving citric acid and thiourea in water, performing ultrasonic dispersion, transferring to a reactor for hydrothermal reaction, and sequentially cooling, rotary steaming and drying to obtain N, S-GQDs;
(b) Dissolving the N, S-GQDs obtained in the step (a) in water, adding cadmium acetate dihydrate, polyvinylpyrrolidone and thioacetamide, mixing, ultrasonically dispersing, transferring to a reactor for hydrothermal reaction, and then sequentially cooling, washing and drying to obtain N, S-GQDs @ CdS;
in the step (a), the temperature of the hydrothermal reaction is 160-200 ℃ and the time is 4-8h.
2. The preparation method of the modified N, S-GQDs @ CdS nano-catalyst as claimed in claim 1, wherein in step (a), the molar ratio of citric acid to thiourea is 1.
3. The preparation method of the modified N, S-GQDs @ CdS nano-catalyst as claimed in claim 1, wherein in step (b), the mass ratio of N, S-GQDs, cadmium acetate dihydrate, polyvinylpyrrolidone and thioacetamide is (0.02-0.06): 0.266:0.2 (0.751-0.1503).
4. The method for preparing the modified N, S-GQDs @ CdS nano-catalyst as claimed in claim 1, wherein in step (b), cadmium acetate dihydrate is usedCd 2+ And S in thioacetamide 2- The molar ratio of (1) to (2) is 1.
5. The method for preparing the modified N, S-GQDs @ CdS nano-catalyst as claimed in claim 1, wherein in step (b), cd in cadmium acetate dihydrate 2+ And S in thioacetamide 2- Is 1.
6. The preparation method of the modified N, S-GQDs @ CdS nano-catalyst as claimed in claim 1, wherein in step (b), the temperature of hydrothermal reaction is 160-200 ℃ and the time is 6-18h.
7. The method for preparing the modified N, S-GQDs @ CdS nano-catalyst as claimed in claim 1, wherein in step (b), cooling to room temperature, washing with absolute ethanol, and drying at 60 ℃ overnight.
CN202110131044.8A 2021-01-30 2021-01-30 Modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof Active CN113042079B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110131044.8A CN113042079B (en) 2021-01-30 2021-01-30 Modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110131044.8A CN113042079B (en) 2021-01-30 2021-01-30 Modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof

Publications (2)

Publication Number Publication Date
CN113042079A CN113042079A (en) 2021-06-29
CN113042079B true CN113042079B (en) 2022-11-15

Family

ID=76508395

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110131044.8A Active CN113042079B (en) 2021-01-30 2021-01-30 Modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof

Country Status (1)

Country Link
CN (1) CN113042079B (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105567230A (en) * 2016-02-22 2016-05-11 桂林理工大学 Nitrogen and sulfur-codoped graphene quantum dot and preparation method thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106179262B (en) * 2016-07-08 2018-07-20 苏州大学 Composite material and preparation method and purposes with absorption-visible light photocatalytic degradation synergistic effect

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105567230A (en) * 2016-02-22 2016-05-11 桂林理工大学 Nitrogen and sulfur-codoped graphene quantum dot and preparation method thereof

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Highly luminescent S, N co-doped graphene quantum dots with broad visible absorption bands for visible light photocatalysts;Qu Dan等;《Nanoscale》;20131007;第2卷(第24期);第12272-12277页 *
水热法制备聚苯乙烯/CdS核壳结构纳米复合颗粒;孙冠华;《材料工程》;20141231(第4期);第89-94页 *
石墨烯量子点/硫化镉纳米复合物的制备及其光催化性质研究;谢关才;《万方学位论文》;20131031;第45-50页 *

Also Published As

Publication number Publication date
CN113042079A (en) 2021-06-29

Similar Documents

Publication Publication Date Title
Jian et al. Photoelectron directional transfer over a gC 3 N 4/CdS heterojunction modulated with WP for efficient photocatalytic hydrogen evolution
CN107376944B (en) Application of transition metal sulfide loaded Mn-Cd-S solid solution in aspect of photocatalytic hydrogen production
CN112642483A (en) N-GQDs-PS @ CdS core-shell nano-catalyst as well as preparation method and application thereof
CN112076777B (en) For CO2Reduced photocatalyst and preparation method thereof
CN113145138B (en) Thermal response type composite photocatalyst and preparation method and application thereof
CN100395025C (en) Method for preparing high stable, reproducible load type photocatalyst of Nano cadmium sulphide
CN111841576A (en) Bi/BiVO rich in oxygen vacancy4Preparation method of-CdS photocatalyst
CN110624595A (en) Calcium-indium-sulfur/titanium carbide photocatalytic composite material and preparation method thereof
CN112774718A (en) Cuprous oxide/tubular graphite-like phase carbon nitride composite catalyst and preparation method and application thereof
CN114950522A (en) Boron nitride/indium zinc sulfide composite photocatalyst and preparation method and application thereof
CN113893840B (en) Composite photocatalyst, preparation method and application in dye wastewater
CN113209988B (en) Cadmium sulfide/silver nanocluster photocatalyst based on electrostatic self-assembly and preparation method and application thereof
Ghasemzadeh et al. Templated synthesis of ZnO quantum dots via double solvents method inside MOF-801 as emerging photocatalyst for photodegradation of Acid Blue 25 under UV light
CN113042079B (en) Modified N, S-GQDs @ CdS nano-catalyst and preparation and application thereof
CN111939957A (en) Preparation method of photocatalytic nitrogen fixation material porous carbon nitride nanofiber/graphene
Li et al. Chemical etching and phase transformation of Nickel-Cobalt Prussian blue analogs for improved solar-driven water-splitting applications
CN108855222B (en) ZCS @ Ni-MOF nanocomposite and preparation and application thereof
CN113145151B (en) Modified N-GQDs @ CdS nano-catalyst and preparation and application thereof
CN111282572B (en) Composite material with near-infrared light catalysis effect and preparation method and application thereof
CN112108168B (en) Preparation method, product and application of zinc oxide modified gallium nitride silver-loaded nanorod heterojunction photocatalyst
CN110586060B (en) Composite photocatalyst with oxidation-reduction performance and preparation method thereof
CN109174129B (en) Double-sensitized titanium dioxide photocatalyst and preparation method thereof
CN112675892B (en) Hollow N, B-GQDs-CdS @ TiO2Nano catalyst and preparation method and application thereof
CN114644320B (en) Photocatalytic hydrogen production system and application thereof
CN113831349B (en) Preparation method of urotropine

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant