CN108499587A - Ag/g-C3N4The preparation of composite visible light catalyst - Google Patents

Abstract

The present invention relates to a kind of Ag/g C₃N₄The preparation method of composite visible light catalyst.Its step is：(1) with melamine for g C₃N₄Raw material, be put into crucible, 550 DEG C be warming up to the rate of 10 DEG C/min in Muffle furnace, 4h, cooled to room temperature is kept to obtain faint yellow solid.(2) a certain amount of g C are weighed₃N₄, a certain amount of ethyl alcohol or ethylene glycol solvent is added, stirs, ultrasonic 30min.(3) 0.02~0.06mol/L AgNO are added dropwise₃Solution stirs 30min.(4) above-mentioned solution is poured into reaction kettle, 110~140 DEG C of 3~5h of heating are cooled to room temperature, are washed with deionized water and absolute ethyl alcohol, and drying grinding obtains ash gray Ag/g C₃N₄Composite visible light catalyst.The visible light catalyst that the present invention obtains there is stronger visible light photocatalytic degradation activity, the simple easy-regulating of the catalyst preparation process, raw material to be easy to get rhodamine B, and production cost is low.

Description

Preparation of Ag/g-C3N4 Composite Visible Light Catalyst

technical field

The invention relates to the preparation of an Ag/gC ₃ N ₄ composite visible light catalyst with visible light activity. It belongs to the technical field of photocatalysis.

Background technique

With the rapid development of industrial technology, environmental pollution has become one of the serious problems threatening human survival and future development. The application of photocatalytic technology is considered to be an effective way to solve the problems of water and air pollution. As a new type of photocatalyst responding to visible light, gC ₃ N ₄ has a unique electronic structure, a narrow band gap and a suitable energy band position, and has high thermal and chemical stability, but it is not sensitive to visible light. Therefore, the preparation of high-efficiency photocatalysts with visible light response is an important topic in the field of photocatalysis research.

Loading nano-Ag particles on gC ₃ N ₄ carrier by solvothermal method is an effective way to expand the visible light response range of gC ₃ N ₄ . Due to the plasmon resonance absorption of nano-Ag particles, the visible light response of the composite photocatalyst can be greatly broadened, and the separation efficiency of photogenerated carriers can be significantly improved, thereby effectively improving its photocatalytic activity. Therefore, nano-Ag particles can be used to expand the gC Visible light response of ₃ N ₄ . The present invention combines nano-Ag particles with gC ₃ N ₄ layered materials through a simple solvothermal method, and prepares Ag/gC ₃ N ₄ composite visible light catalysts with different mass ratios, so that its absorption spectrum is extended to the visible light region , thereby improving the photocatalytic efficiency.

Patent application CN 104475140A adds silver nitrate solution dropwise to dicyandiamide or melamine dispersion, puts the obtained product into a high-temperature atmosphere furnace, and obtains Ag/gC ₃ N ₄ composite photocatalyst under the protection of nitrogen. It has good photocatalytic degradation effect on organic dye rhodamine B. However, the size of the Ag particles obtained by this method is relatively large, and the preparation process is relatively complicated. This patent uses layered gC ₃ N ₄ as the carrier and nano-Ag particles as the carrier. Ag/gC ₃ N ₄ composite visible light catalysts with different mass ratios are synthesized by a one-step solvothermal method, and the nano-Ag particles are evenly loaded on gC ₃ N On the ₄ -layer carrier, the unique plasmon resonance effect of nano-silver is used to broaden the visible light response range of the composite photocatalyst, improve its photocatalytic performance, and show efficient visible light catalytic degradation of rhodamine B activity.

Contents of the invention

In order to solve the above problems, the present invention adopts the technical scheme as follows: Ag/gC ₃ N ₄ composite photocatalysts with different mass ratios prepared by solvothermal method, according to the content of the claims, it is characterized in that it comprises the following steps:

(1) Using melamine as the gC ₃ N ₄ raw material, put it into a crucible, heat up to 550°C in a muffle furnace at a rate of 10°C/min, keep it for 4h, and naturally cool to room temperature to obtain a light yellow solid;

(2) Weigh a certain amount of gC ₃ N ₄ , add 60-80 mL of solvent, the solvent is ethanol or ethylene glycol, stir, and ultrasonically disperse for 30 minutes;

(3) While stirring the gC ₃ N ₄ solution, add dropwise 0.02-0.06mol/L AgNO ₃ solution, and stir for 30 minutes;

(4) Pour the stirred solution into a reaction kettle, heat at 110-140° C. for 3-5 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

According to the above scheme, the solvent described in step (2) includes ethanol and ethylene glycol, and the addition amount is 60-80 mL.

According to the above scheme, the concentration of the AgNO ₃ solution in step (3) is 0.02-0.06 mol/L, and the m(Ag)/m(gC ₃ N ₄ ) is 5-30.

According to the above scheme, the heating temperature in the reactor described in step (4) is 110-140° C., and the heating time is 3-5 hours.

The photocatalytic activity of the prepared Ag/gC ₃ N ₄ composite photocatalyst under visible light irradiation was evaluated by using rhodamine B as a probe molecule. Weigh 0.1g catalyst sample and add it to 100mL, 0.01g/L RB aqueous solution, ultrasonication for 10min, dark reaction for 30min, light source is 500W xenon lamp, visible light is obtained by filter with cut-off wavelength of 400nm, light intensity is 12mW/ ^cm2 . During the reaction, keep the distance between the light source and the liquid surface in the beaker at 15 cm, take samples every 10 minutes, centrifuge the reaction suspension, and measure the absorbance value of RB at 554 nm with a 752-type ultraviolet-visible spectrophotometer, which is drawn by the Lambert-Beer law Draw the curve C/Co~t of the relative concentration with time.

Advantages of the present invention: gC ₃ N ₄ is prepared as a carrier by a simple thermal polymerization method, and a new Ag/gC ₃ N ₄ composite visible light catalyst is synthesized through a one-step ethanol solvothermal reduction method, which can effectively degrade rhodamine B dye under visible light . Nano-Ag particles are loaded on the gC ₃ N ₄ sheet carrier, which broadens the range of visible light absorption and improves the photocatalytic performance of the composite catalyst, and the performance is good after repeated test evaluations. The preparation process is simple and easy to control, the production cost is low, and it is suitable for mass production.

Description of drawings

Fig. 1 Process flow chart for preparing Ag/gC ₃ N ₄ composite visible light catalyst.

Figure 2Ag/gC ₃ N ₄ composite visible photocatalyst TEM photo,

Fig. 3 Curve of photocatalytic degradation of rhodamine B by Ag/gC ₃ N ₄ composite visible light catalyst.

Detailed ways

The present invention will be described in further detail below in conjunction with examples, but the protection scope of the present invention is not limited to these examples.

Example 1

₅ %Ag/ _gC3N4

(1) Add 1 g of gC ₃ N ₄ into 50 mL of ethanol solvent; sonicate for 30 min.

(2) Add 10 mL of 0.045 mol/L AgNO _solution dropwise, and stir for 30 min;

(3) Pour the prepared solution into a reaction kettle, heat at 120° C. for 3 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray 5% Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

Example 2

10%Ag _{/ gC3N4}

(1) Add 1 g of gC ₃ N ₄ into 50 mL of ethanol solvent; sonicate for 30 min.

(2) Add 20mL of 0.045mol/L _AgNO3 solution dropwise, and stir for 30min;

(3) Pour the prepared solution into a reaction kettle, heat at 120° C. for 3 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray 10% Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

Example 3

15 _% Ag/ _gC3N4

(1) Add 1 g of gC ₃ N ₄ into 50 mL of ethanol solvent; sonicate for 30 min.

(2) Add 30 mL of 0.045 mol/L _AgNO3 solution dropwise, and stir for 30 min;

(3) Pour the prepared solution into a reaction kettle, heat at 120° C. for 3 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray 15% Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

20%Ag _{/ gC3N4}

(1) Add 1 g of gC ₃ N ₄ into 50 mL of ethanol solvent; sonicate for 30 min.

(2) Add 40 mL of 0.045 mol/L AgNO _solution dropwise, and stir for 30 min;

(3) Pour the prepared solution into a reaction kettle, heat at 120° C. for 3 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray 20% Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

Example 5

₂₅ %Ag/ _gC3N4

(1) Add 1 g of gC ₃ N ₄ into 50 mL of ethanol solvent; sonicate for 30 min.

(2) Add 50 mL of 0.045 mol/L AgNO _solution dropwise, and stir for 30 min;

(3) Pour the prepared solution into a reaction kettle, heat at 120° C. for 3 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray 25% Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

Example 6

30%Ag _{/ gC3N4}

(1) Add 1 g of gC ₃ N ₄ into 50 mL of ethanol solvent; sonicate for 30 min.

(2) Add 60mL of 0.045mol/L _AgNO3 solution dropwise, and stir for 30min;

(3) Pour the prepared solution into a reaction kettle, heat at 120° C. for 3 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray 5% Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

Example 7

25%Ag/gC ₃ N ₄ heated at 140°C

(1) Add 1 g of gC ₃ N ₄ into 50 mL of ethanol solvent; sonicate for 30 min.

(2) Add 50 mL of 0.045 mol/L AgNO _solution dropwise, and stir for 30 min;

(3) Pour the prepared solution into a reaction kettle, heat at 140° C. for 3 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray 25% Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

Example 7

25%Ag/gC ₃ N ₄ with heating time of 5h

(1) Add 1 g of gC ₃ N ₄ into 50 mL of ethanol solvent; sonicate for 30 min.

(2) Add 50 mL of 0.045 mol/L AgNO _solution dropwise, and stir for 30 min;

(3) Pour the prepared solution into a reaction kettle, heat at 120° C. for 5 h, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray 25% Ag/gC ₃ N ₄ composite visible light catalyst was obtained.

Claims (6)

1. The preparation of Ag/gC ₃ N ₄ composite visible light catalyst is characterized in that using lamellar gC ₃ N ₄ as a carrier, and nano-Ag as a loading agent, comprising the following steps: (1) Using melamine as the gC ₃ N ₄ raw material, put it into a crucible, heat up to 550°C in a muffle furnace at a rate of 10°C/min, keep it for 4h, and naturally cool to room temperature to obtain a light yellow solid; (2) Weigh a certain amount of gC ₃ N ₄ , add 60-80 mL of solvent, the solvent is ethanol or ethylene glycol, stir, and ultrasonically disperse for 30 minutes; (3) While stirring the gC ₃ N ₄ solution, add dropwise 0.02-0.06mol/L AgNO ₃ solution, and stir for 30 minutes; (4) Pour the stirred solution into a reaction kettle, heat at 110-140° C. for 3-5 hours, cool to room temperature, wash with deionized water and absolute ethanol, dry and grind. A light gray Ag/gC ₃ N ₄ composite visible light catalyst was obtained. 2. The preparation of the Ag/gC ₃ N ₄ composite visible light catalyst according to claim 1, characterized in that: the solvent includes ethanol and ethylene glycol, and the addition amount is 60-80 mL. 3. The preparation of the Ag/gC ₃ N ₄ composite visible light catalyst according to claim 1, characterized in that the concentration of the AgNO ₃ solution added dropwise is 0.02-0.06 mol/L. 4. The preparation of Ag/gC ₃ N ₄ composite visible light catalyst according to claim 1, characterized in that m(Ag)/m(gC ₃ N ₄ ) is 5-30. 5. The preparation of Ag/gC ₃ N ₄ composite visible light catalyst according to claim 1, characterized in that: the heating temperature in the reactor is 110-140°C. 6. The preparation of the Ag/gC ₃ N ₄ composite visible light catalyst according to claim 1, characterized in that: the heating time in the reactor is 3-5 hours.