CN104722324A

CN104722324A - Method for preparing Ag-g-C3N4/TiO2 ternary complex by three-step method

Info

Publication number: CN104722324A
Application number: CN201510042379.7A
Authority: CN
Inventors: 吴小琴; 柳泽斌; 夏冬冬; 陈天泽
Original assignee: Nanchang Hangkong University
Current assignee: Nanchang Hangkong University
Priority date: 2015-04-02
Filing date: 2015-04-02
Publication date: 2015-06-24

Abstract

The invention discloses a method for preparing an Ag-g-C3N4/TiO2 ternary complex by a three-step method. The method is characterized by comprising the following steps: firstly, heating a reagent (melamine) to 540 DEG C, and cracking the reagent into graphite-like carbonized nitrogen (g-C3N4); further performing ultrasonic mixing to enable P25 to load g-C3N4; and finally, doping silver with an immobilized sol process and synthesizing a target product. A composite photocatalyst with the structure has high visible-light activity so as to become an important sewage treating agent with potential research value. The method disclosed by the invention has the advantages of simple reaction condition, moderate and stable reaction and easy large-scale production.

Description

Three-step approach produces Ag-g-C 3n 4/ TiO 2the method of ternary complex

Technical field

The present invention relates to a kind of preparation method of ternary complex, particularly relate to a kind of three-step approach and produce Ag-g-C ₃n ₄ /tiO ₂the method of ternary complex.

Background technology

Ag-g-C ₃n ₄ /tiO ₂ternary can compound be a kind of visible-light photocatalyst, because of this Three-element composite photocatalyst tool visible light activity, thus becomes a kind of important sewage-treating agent with potential researching value.More to the research of binary composite photo-catalyst both at home and abroad, but not yet there is preparation Ag-g-C ₃n ₄ /tiO ₂the report of Three-element composite photocatalyst.Therefore without the preparation method of complete this Three-element composite photocatalyst of synthesis; The present invention take melamine as primary raw material, successively by Pintsch process, ultrasonic mixing, immobilization colloidal sol three step process, finally obtained target product.

Summary of the invention

A kind of three-step approach is the object of the present invention is to provide to produce Ag-g-C ₃n ₄ /tiO ₂the method of ternary complex, this preparation method take melamine as raw material, successively by Pintsch process, ultrasonic mixing, immobilization colloidal sol three step finally obtained Ag-g-C ₃n ₄ /tiO ₂tri compound high-performance optical catalyst.

The present invention is achieved like this, and it is characterized in that preparation method is:

Step 1, melamine is loaded in porcelain crucible, is placed in Muffle furnace, slowly rises to temperature 540 by room temperature ^oc, and after constant temperature 2 h, Temperature fall.Take out after being cooled to room temperature, after weighing, sample is ground into powder and obtains light yellow photochemical catalyst g-C ₃n ₄.

Step 2, take TiO2 solid powder, be placed in Rotary Evaporators, add ethanol solution, then add the g-C3N4 that step 1 obtains, the weight ratio 1:2-10 of TiO2 and g-C3N4.Then ultrasonic mixing 15 min disperses completely to powder.80 ^oc vacuum drying 5 h obtains powder, after grinder grinding, in Muffle furnace 400 ^o2 h are calcined under C condition.Temperature fall.Take out after being cooled to room temperature, then be ground into powder with grinder, obtain binary composite photo-catalyst g-C ₃n ₄ /tiO ₂.

Step 3, collargol pass through NaBH ₄make reducing agent oxidation AgNO ₃and obtain, and make protective agent to reach good dispersiveness with polyvinyl alcohol (PVA).

Detailed process is as follows: get 8 mL AgNO ₃the aqueous solution (Ag content is 1.60 mgmL ^-1i.e. 12.8 mg, 0.1187 mmol Ag), mix with protective agent PVA (getting 8.5 mg PVA to be dissolved in 8.0 ml water) in ice-water bath ( m _ag: m _pVA=1.5:1) and vigorous stirring, then add NaBH fast ₄the aqueous solution, Ag and NaBH ₄mol ratio be 1:5.NaBH ₄solution: by 22.45 mg NaBH ₄be dissolved in 9.60 mL water, when colloidal sol becomes black from colourless, show that silver sol is formed.In ultrasonic cavitation and under stirring, by load capacity m _ag: m _tiO2about=1.0% carrier g-C ₃n ₄/ TiO ₂join in silver sol suspension, both maintenances contact, until all absorb, obtains target product Ag-g-C ₃n ₄ /tiO ₂, then wet solid catalyst is placed in 80 ° of C drying boxes dry.Rearmounted drier in be cooled to room temperature, after weighing preserve, obtain Three-element composite photocatalyst Ag-g-C3N4/TiO2.

Advantage of the present invention is: employing Pintsch process melamine prepares g-C3N4, the ultrasonic g-C3N4/TiO2 of being mixed with, Ag-g-C prepared by immobilization colloidal sol ₃n ₄ /tiO ₂, three-steps process reaction condition is simple, reaction temperature and and stable, be easy to amplify and produce.

Accompanying drawing explanation

Fig. 1 is that the UV-vis DRS of embodiment of the present invention gained sample composes.

Fig. 2 is the visible light activity of different photochemical catalyst of the present invention.

Detailed description of the invention

1. melamine pyrolysis prepares g-C ₃n ₄

Take 3 g melamines and be placed in 50 mL porcelain crucibles, put into Muffle furnace, rise to temperature 540 by room temperature ^oc, after constant temperature 2 h, Temperature fall.Take out after being cooled to room temperature, obtain g-C ₃n ₄, after weighing, be ground into powder sample preservation.

2. be ultrasonicly mixed with g-C ₃n ₄ /tiO ₂

Take 0.10 gTiO respectively ₂pressed powder four parts is placed in four 100 mL beakers, respectively adds ethanol solution 50 mL, then adds the g-C of 0.002 g, 0.004 g, 0.008 g, 0.01 g respectively ₃n ₄powder, namely obtains g-C ₃n ₄ /tiO ₂mass ratio is respectively: 2%, 4%, 8%, 10%.Then ultrasonic mixing 15 min disperses completely to powder.80 ^oc is dry, and 5 h obtain powder with evaporate to dryness, to be placed in Muffle furnace 400 after grinding ^o2 h are calcined under C condition.Temperature fall.Take out after being cooled to room temperature, after having claimed, be ground into powder sample preservation.

3, fixing solation technique prepares target product Ag-g-C ₃n ₄ /tiO ₂

Detailed process is as follows: the AgNO getting 8 mL ₃(Ag content is 1.60 mgmL to the aqueous solution ^-1, i.e. 12.8 mg, 0.1187 mmol Ag), mix with protective agent PVA (getting 8.6 mg PVA to be dissolved in 8.0 ml water) in ice-water bath ( m _ag: m _pVA=1.5:1) and vigorous stirring, then add NaBH fast ₄the aqueous solution (22.45 mg NaBH ₄be dissolved in 9.60 mL water) ( n _ag: n _naBH4=1:5), when colloidal sol becomes black from colourless, show that silver sol is formed.In ultrasonic cavitation and under stirring, by load capacity m _ag: m _g-C3N4/TiO2=0.5,1.0,1.5,2.0,3.0% carrier g-C ₃n ₄ /tiO ₂join in silver sol suspension, both maintenances contact, until all absorb, obtains target product Ag-g-C ₃n ₄ /tiO ₂.Then wet solid catalyst is placed in 80 ° of C drying boxes dry.Rearmounted drier in be cooled to room temperature, after weighing preserve.

4, photochemical catalyst characterizes and tests with photocatalysis performance

as shown in Figure 1 and Figure 2, with UV-Vis diffuse reflection spectroscopy, photochemical catalyst sample is characterized, and (it is 10 mg that 100 mg catalyst add 100 mL concentration to determine the ability of photocatalyst for degrading methylene blue (MB) /in the MB of L, under lucifuge stirring condition, adsorb 2 h, add 420 nm optical filters afterwards, then irradiate 4 h) with 500 W xenon lamps.

Claims

1. three-step approach produces Ag-g-C ₃n ₄ /tiO ₂the method of ternary complex, is characterized in that method step is:

Step 1, melamine is loaded in porcelain crucible, is placed in Muffle furnace, slowly rises to temperature 540 by room temperature ^oc, and after constant temperature 2 h, Temperature fall, takes out after being cooled to room temperature, after weighing, is ground into powder by sample and obtains light yellow photochemical catalyst g-C ₃n ₄;

Step 2, take TiO2 solid powder, be placed in Rotary Evaporators, add ethanol solution, then add the g-C3N4 that step 1 obtains, the weight ratio 1:2-10 of TiO2 and g-C3N4, then ultrasonic mixing 15 min disperses completely to powder, and 80 ^oc vacuum drying 5 h obtains powder, after grinder grinding, in Muffle furnace 400 ^o2 h are calcined, Temperature fall under C condition; Take out after being cooled to room temperature, then be ground into powder with grinder, obtain binary composite photo-catalyst g-C ₃n ₄ /tiO ₂;

Step 3, collargol pass through NaBH ₄make reducing agent oxidation AgNO ₃and obtain, and make protective agent to reach good dispersiveness with polyvinyl alcohol;

Detailed process is as follows: get 8 mL AgNO ₃the aqueous solution, wherein Ag content is 1.60 mgmL ^-1, mix with protective agent PVA in ice-water bath, wherein m _ag: m _pVA=1.5:1, and vigorous stirring, then add NaBH fast ₄the aqueous solution, Ag and NaBH ₄mol ratio be 1:5; NaBH ₄solution: by 22.45 mg NaBH ₄be dissolved in 9.60 mL water, when colloidal sol becomes black from colourless, show that silver sol is formed, in ultrasonic cavitation and under stirring, by load capacity m _ag: m _tiO2about=1.0% carrier g-C ₃n ₄/ TiO ₂join in silver sol suspension, both maintenances contact, until all absorb, obtains target product Ag-g-C ₃n ₄ /tiO ₂, then wet solid catalyst is placed in 80 ° of C drying boxes dry, rearmounted drier in be cooled to room temperature, preserve after weighing, obtain Three-element composite photocatalyst Ag-g-C3N4/TiO2.