The method of carbonitride/argentum nano composite material is prepared in a kind of chemical reducing agent reduction
Technical field
The present invention relates to a kind of method of nano composite material, especially a kind of preparation technology is simple, with low cost, and product has the preparation method of the carbonitride-silver nano particle composite material of good photocatalytic activity.
Technical background
In recent years, the material with carbon element of graphite-like structure, as the extensive use of Graphene and boron doping carbonitride (B-CN) is found gradually.Graphite-phase carbonitride (g-C
3n
4) be a kind of Novel non-metal polymer semiconductor photochemical catalyst (Wong, Nature Mater., 2009,8:76-80), it has stacked two-dimensional structure, less energy gap (2.7 eV), spectral response range is wider.With respect to inorganic semiconductor, graphite-phase carbonitride is comprised of elemental carbon and nitrogen the abundantest on our celestial body, is a kind of continuable, eco-friendly organic semiconductor.Preparation technology is simple for graphite-phase carbonitride, and cheap advantage is unique.Due to the people such as king reported its photocatalysis performance (Wang, Science, 2009,324:768-771), the application that graphite-phase carbonitride is strengthened in catalysis and photovoltaic field is found.
In general, catalyst can pass through supported precious metal nano-particle, to promote separation of charge, and then improves catalytic activity.Verified, the plasma resonance effect that the collective oscillation of silver nano-grain surface electronic produces has been made huge contribution to the photocatalytic activity of money base semiconductor composite.Silver plasma resonance peak at visible region, thereby caused the strong absorption to sunshine.In addition, the electric conductivity that Nano silver grain is good can improve electric transmission, makes the carrier fast transfer producing to silver surface, thereby suppresses the compound of electron-hole pair.In prior art, there have been some reports about preparation and the application of carbonitride-silver nano particle composite material.For example, Holland < < applied catalysis > > (Applied Catalysis A:General, 215 pages of 409-410 phases in 2011) reported a kind of preparation method of carbonitride/silver, the method utilizes solvent evaporates, thermal reduction to make carbonitride-Yin mixture, and has analyzed its application aspect photocatalytic degradation of dye and photocatalysis hydrogen production; Holland < < applied catalysis > > (Applied Catalysis B:Environmental, 2013 142-143 phase 828 pages) has reported and has utilized photoreduction legal system for carbonitride/argentum nano composite material.
Although the preparation method of carbonitride/silver nano particle composite material has had some reports, but the Nano silver grain in the composite of above-mentioned report size is homogeneous, dispersed bad, easy gathering etc. not, and these have all had a strong impact on the serviceability of composite.Therefore, by gentle liquid phase chemical reduction method, on carbonitride surface, generate the Nano silver grain of big or small homogeneous, favorable dispersibility, thereby prepare carbonitride/argentum nano composite material, have great importance.
Summary of the invention
For above-mentioned prior art, the invention provides the preparation method that carbonitride/silver nano particle composite material is prepared in a kind of chemical reducing agent reduction.Adopt DMF (DMF) as reducing agent, graphite-phase carbonitride prepared by thermal decomposition melamine is carrier, under gentle reaction condition, silver on nitrogenize carbon-coating nucleation, grow up, obtain carbonitride/silver nano particle composite material.This preparation method's technique is simple, and synthetic carbonitride/silver composite material purity is high, and impurity content is few.Carbonitride/the silver nano particle composite material being synthesized by preparation method of the present invention is in catalytic field extensive application, also can expand it simultaneously in the application in electrochemistry, the field such as antibacterial.
The method of carbonitride/silver nano particle composite material is prepared in a kind of chemical reducing agent reduction of the present invention, and this preparation method realizes by following steps:
(1) by graphite-phase carbonitride, the ratio with 6 ~ 10mg/mL is scattered in DMF solution, and ultrasonic dispersion obtains the dispersion liquid of carbonitride;
(2) according to the mass ratio of graphite-phase carbonitride and silver nitrate, be within 6: 1 ~ 120: 1, to take silver nitrate, silver nitrate is scattered in DMF, and add surfactant polyvinylpyrrolidone (PVP), and its quality is 1 ~ 1.5 times of silver nitrate quality, magnetic agitation makes silver nitrate dispersion liquid;
(3) above-mentioned steps one two kinds of solution preparing with step 2 that prepare are mixed, after magnetic agitation, transfer in a there-necked flask, heating water bath to 80 ~ 90 ℃, reaction, reacts 10 ~ 20h while stirring;
(4) solution centrifugal above-mentioned steps three having been reacted, obtains carbonitride/silver composite precipitation; Then with distilled water cyclic washing until remove unconjugated Nano silver grain; Finally product is cleaned with ethanol, after being dried, obtain carbonitride-Nano silver grain compound;
(5) utilize SEM (SEM), X-ray diffractometer (XRD), X ray electron spectrum (XPS), transmission electron microscope (TEM) to carry out Morphology Structure Analysis to product, methyl orange (MO) solution of take carries out photocatalytic degradation experiment as target dyestuff, by ultraviolet-visible spectrophotometer, measure absorbance, to assess its photocatalytic activity.
Ultrasonic dispersion in described step 1 refers to: at 40kHz, and ultrasonic processing 30min ~ 90min in the ultrasonic cleaner of 100W.
In described step 2, the time of magnetic agitation is 30 ~ 60min.
The time of the magnetic agitation in described step 3 is 10 ~ 30min.
In silver nitrate dispersion liquid in described step 2, the concentration of silver nitrate is 0.005mol/L ~ 0.03mol/L.
Centrifugal condition in described step 4 is: the centrifugal 3 ~ 5min of 4000 ~ 8000rmp.
In the vacuum drying chamber that dry finger in described step 4 is 100kPa in vacuum, at 30 ~ 60 ℃, be dried 12 ~ 24h.
Wherein, the graphite-phase carbonitride in step 1 can be used melamine, cyanamid dimerization or the preparation of urea thermal decomposition method; In addition, in step 3, can prevent with condensing unit that the evaporation of solvent, its condensing unit from being straight shape or spherical condensation tube.
Compared with prior art, advantage of the present invention is:
(1) directly on nitrogenize carbon-coating, generate silver nano-grain, the composite impurity content of preparation is low, applied range.
(2) less at the silver nano-grain particle diameter of carbonitride Surface Realize, be evenly distributed, firm with the combination of carbonitride.
The present invention has that technique is simple, the feature of simple operation, excellent product performance, and the synthetic carbonitride-silver nano particle composite material of this method has potential extensive use at catalysis, photoelectric field.
Accompanying drawing explanation
Fig. 1 is the stereoscan photograph of the prepared carbonitride/silver composite material of embodiment 1;
Fig. 2 is the EDS analysis result of the prepared carbonitride/silver composite material of embodiment 1;
Fig. 3 is the X-ray diffraction analysis figure of the prepared carbonitride/silver composite material of embodiment 1;
Fig. 4 is the XPS Determination of Different Valence States of Ag element in the prepared carbonitride/silver composite material of embodiment 1;
Fig. 5 is the transmission electron microscope photo of the prepared carbonitride/silver composite material of embodiment 1;
Fig. 6 is the time m-degradation rate graph of a relation of pure carbonitride and carbonitride/silver nano particle composite material photo-catalytic degradation of methyl-orange (MO) solution.
The specific embodiment
the preparation of embodiment 1 carbonitride/silver nano particle composite material
The graphite-phase carbonitride of getting 0.27g is scattered in the N of 30mL, in dinethylformamide (DMF) solution, at 40kHz, 100W power ultrasonic is processed, process 30min, thereby the reunion of breaking carbonitride is dispersed in DMF solution nitrogenize carbon plate uniformly, make thus DMF (DMF) solution of carbonitride; The silver nitrate that takes 45mg is scattered in the DMF of 10mL, then adds the polyvinylpyrrolidone (PVP) of 50mg, magnetic agitation 40min; By the N of above-mentioned carbonitride, the N of dinethylformamide (DMF) solution and silver nitrate, dinethylformamide (DMF) solution mixes, and magnetic agitation 30min, then transfers in a there-necked flask, reaction while stirring in the water-bath of 80 ℃, reaction 20h, the centrifugal 5min of solution 5000rmp after having reacted, removes upper strata waste liquid, to be precipitated product distilled water cyclic washing, remove unconjugated Nano silver grain; Finally product is cleaned with ethanol, and in vacuum drying chamber at 30 ℃ dry 24h obtain product of the present invention: carbonitride-silver nano particle composite material.
the preparation of embodiment 2 carbonitrides/silver nano particle composite material
The graphite-phase carbonitride of getting 0.27g is scattered in the DMF solution of 30mL, and at 40kHz, 100W power ultrasonic is processed, and process 60min, thereby the reunion of breaking carbonitride is dispersed in DMF solution nitrogenize carbon plate uniformly; The silver nitrate that takes 22.5mg is scattered in the DMF of 10mL, then adds the polyvinylpyrrolidone (PVP) of 25mg, magnetic agitation 30min; Above-mentioned two kinds of solution are mixed, magnetic agitation 15min, then transfer in a there-necked flask, reaction while stirring in the water-bath of 85 ℃, reaction 16h, the centrifugal 5min of solution 6000rmp after having reacted, removes upper strata waste liquid, by precipitated product distilled water cyclic washing, remove unconjugated Nano silver grain; Finally product is cleaned with ethanol, and in vacuum drying chamber at 40 ℃ dry 18h obtain carbonitride/silver powder and be product of the present invention: carbonitride-silver nano particle composite material.
the preparation of embodiment 3 carbonitrides/silver nano particle composite material
The graphite-phase carbonitride of getting 0.27g is scattered in the DMF solution of 30mL, and at 40kHz, 100W power ultrasonic is processed, and process 90min, thereby the reunion of breaking carbonitride is dispersed in DMF solution nitrogenize carbon plate uniformly; The silver nitrate that takes 9mg is scattered in the DMF of 10mL, then adds the polyvinylpyrrolidone (PVP) of 10mg, magnetic agitation 30min; Above-mentioned two kinds of solution are mixed, magnetic agitation 20min, then transfer in there-necked flask, reaction while stirring in the water-bath of 90 ℃, reaction 12h, the centrifugal 4min of solution 7000rmp after having reacted, removes upper strata waste liquid, by precipitated product distilled water cyclic washing, remove unconjugated Nano silver grain; Finally product is cleaned with ethanol, and in vacuum drying chamber at 45 ℃ the carbonitride/silver powder of dry 12h gained be product of the present invention: carbonitride-silver nano particle composite material.
the photocatalytic activity experiment of the pure carbonization nitrogen of embodiment 4 and carbonitride/silver nano particle composite material
(1) methyl orange (MO) solution that compound concentration is 10mg/L, is placed in dark place by the solution preparing;
(2) take each 30mg of carbonitride and carbonitride/silver composite material, be placed in respectively photo catalysis reactor, the target degradation solution (every 60ml methyl orange solution adds respectively 30mg carbonitride and carbonitride/silver composite material) that adds 60mL step (1) to prepare, dark place magnetic agitation 30min is after catalyst is uniformly dispersed, open water source, light source, carries out photocatalytic degradation experiment;
(3) every 1h draws the photocatalytic degradation liquid in reactor, centrifugal after for the measurement of ultraviolet-visible absorbance.
Fig. 1 is scanning electron microscope (SEM) photograph, and we can find out, carbonitride favorable dispersibility, and the silver nano-grain of carbonitride top layer absorption has effectively stoped the reunion of carbonitride; Fig. 2 is the analysis result of EDS, surface this composite by silver, carbon and nitrogen, formed; Fig. 3 is that XRD analysis result shows: 2 diffraction maximums are the characteristic peak of carbonization nitrogen, has two crystal faces, and the corresponding indices of crystallographic plane are followed successively by (100) from inside to outside, (002), and the load of silver has weakened carbonization nitrogen diffraction peak intensity; Fig. 4 represents that 3d doublet has the feature at the Ag3d peak of 6.0eV division, this and metal A g
0simple substance is consistent; From Fig. 5, we can find out, silver nano-grain adsorbed close is on the surface of carbonitride, and grain size little (average grain diameter 10nm), is evenly distributed; As seen from Figure 6, in photo-catalytic degradation of methyl-orange experiment, carbonization nitrogen/silver nano particle composite material shows excellent photocatalytic activity than pure carbonitride, and carbonitride/silver composite material methyl orange (MO) solution degradation rate after catalytic reaction 4h has reached 80%.