CN106140129A - Metal doping nano TiO2photocatalyst and preparation method thereof - Google Patents

Abstract

The invention provides a kind of metal doping nano TiO₂The preparation method of photocatalyst, this preparation method is as follows: added by butyl titanate in dehydrated alcohol, adds diethanolamine and is uniformly dispersed as inhibitor, magnetic agitation, standby as reactant 1；Add the nitrate of metal ion in deionized water, after fully dissolving, add dehydrated alcohol mix homogeneously, standby as reactant 2；Stir while reactant 2 is added dropwise in reactant 1 with certain speed, regulate PH=4, stir 2h, ageing 12h and form gel, at 450～550 DEG C, prepare described photocatalyst at Muffle kiln roasting 2.5h.Result shows, controls to be 1/4S by rate of addition when preparing colloidal sol, and during roasting, temperature controls have good catalytic effect at 500 DEG C of obtained catalyst.The advantage of the method is: obtained catalyst is high to pollutant catalytic efficiency, preparation method is simple.

Description

Metal doping nano TiO2Photocatalyst and preparation method thereof

Technical field

The invention belongs to catalyst field, particularly relate to metal doping nano TiO₂Photocatalyst and preparation method thereof.

Background technology

TiO₂Photocatalysis technology research in terms of air treating and sewage disposal in recent years is more and more extensive, holding for environment Supervention exhibition has far reaching significance.But due to current nano-TiO₂It is low to there is the efficiency of light energy utilization in powder and colloidal sol in terms of processing waste water Etc. defect, air cleaning is also difficult to because contaminated area is excessive actual application.Photocatalyst is modified such as doping, The catalyst response range to light can be suitably widened in acidifying or coupling, improves the catalyst utilization rate to light.

TiO₂Detitanium-ore-type, brookite type and rutile-type can be divided into according to crystal formation difference.Wherein Detitanium-ore-type and rutile Type structurally has the biggest identical point, all ranges tetragonal crystal system, and difference is between the octahedral structure that both are internal Connected mode and distortion level are inconsistent, and this species diversity in structure makes rutile-type and Detitanium-ore-type TiO₂Mass density and energy Band structure is different, and the energy gap of anatase is 3.3eV, and mass density is 3.9g/cm³；The energy gap of rutile is 3.1eV, lower slightly In anatase, mass density is 4.2g/cm³.Anatase TiO₂High-specific surface area make it have stronger absorbability, and be subject to Light excites the electronics of generation and hole to be not easy to be combined, and catalytic performance is higher, and be typically used as photocatalyst research is all anatase Type.

Ion doping is exactly at nano-TiO₂Lattice in introduce other ions appropriate, cause surface defect or degree of crystallinity to change Become, thus the compound obstruction that causes to light induced electron Yu hole, or make nano-TiO₂Absorbing wavelength red shift, improve it to can See the utilization rate of light, thus improve its photocatalysis effect.

Summary of the invention

For solving above-mentioned technical problem, one aspect of the present invention provides one and prepares metal doping nano TiO simply, easily₂Light The method of catalyst.Specifically include following steps:

(1) 19ml butyl titanate is slowly added in 50ml dehydrated alcohol, add 27ml diethanolamine as inhibitor, Magnetic agitation 1.5h is uniformly dispersed, as reactant 1.

(2) in 10ml deionized water, add the Zn of identical molar percentage²⁺, Cu²⁺, La³⁺Nitrate, after fully dissolving, Add 25ml dehydrated alcohol mix homogeneously, as reactant 2.

(3) stir while reactant 2 is added dropwise in reactant 1 with certain speed, regulate PH=4, stir 2h. Ageing 12h forms gel, at Muffle kiln roasting 2.5h at 450-550 DEG C.

Further, described the rate of addition that reactant 2 is added drop-wise in reactant 1 is defined to 1/4S.

Further, described is 500 DEG C by gel at the limit temperature of Muffle kiln roasting.

Another aspect of the present invention provides a kind of metal doping nano TiO₂Photocatalyst, is prepared from by said method.

Further, nano-TiO it is entrained in described in₂In metal be Zn, its doping is 0.15%, or described in be entrained in Nano-TiO₂In metal be Cu, its doping is 0.2%, or described in be entrained in nano-TiO₂In metal be La, its Doping is 0.15%, or described in be entrained in nano-TiO₂In metal be La and Zn, the doping of described La is 0.1%, The doping of Zn is 0.05%.

It is an advantage of the current invention that:

(1) preparation method of this catalyst is simple, convenient；Catalyst itself does not have toxicity, cheap, is catalyzed pollutant Efficiency is high, and specific grain surface is long-pending big, high to pollutants removal rate.

(2) under this catalyst normal temperature normal pressure it is labile organic compound, complete decomposition, do not produce secondary pollution, there is higher answering By value.

Accompanying drawing explanation

Fig. 1 be rate of addition be respectively 1/0.5S, 1/2S, 1/4S (from left to right) time nano-TiO₂SEM Figure.

Fig. 2 is nano-TiO under different sintering temperature₂XRD figure, wherein, a (450 DEG C), b (500 DEG C), c (550 DEG C) A is anatase peak, and R is rutile peak.

Fig. 3 is Zn under different sintering temperature²⁺Ion-doped nano TiO₂XRD figure, wherein a (450 DEG C), b (500 DEG C), C (550 DEG C), A are anatase peak, and R is rutile peak, and E is ZnTiO₃Peak.

Fig. 4 is Cu under different sintering temperature²⁺Ion-doped nano TiO₂XRD figure, wherein a (450 DEG C), b (500 DEG C), C (550 DEG C), A are anatase peak, and R is rutile peak.

Fig. 5 is La under different sintering temperature³+ ion-doped nano TiO₂XRD figure, wherein a (450 DEG C), b (500 DEG C), C (550 DEG C), A are anatase peak.

Fig. 6 is the nano-TiO under different metal doping₂Degradation rate figure to methyl orange.

Fig. 7 is metal doping nano TiO₂The degradation rate of methyl orange is schemed over time.

Fig. 8 is La-Zn co-doped nano TiO₂The degradation rate of methyl orange is schemed over time.

Detailed description of the invention

Below in conjunction with specific embodiment, technical scheme is described further.

Embodiment 1

In 19ml butyl titanate, add 50ml dehydrated alcohol mix homogeneously, under moderate-speed mixer, add 27m1 diethanolamine, magnetic Power stirring 1.5h, as reactant 1.10ml deionized water is mixed homogeneously with 25ml dehydrated alcohol, as reactant 2. Stir while by reactant 2 respectively with 1/0.5S, 1/2S, the speed of 1/4S be added dropwise in reactant 1, Regulation PH=4, stands after stirring 2h.Obtain water white transparency colloidal sol, become solid gel shape after ageing 12h, solid gel is existed Muffle kiln roasting 2.5h.Sintering temperature is 450 DEG C.

To the three kinds of nano-TiOs obtained₂Carry out sem analysis, as shown in Figure 1.As seen from the figure, rate of addition is different, obtains The granular size of product and pattern the most different, rate of addition is the fastest, nano-TiO₂The most easily reunite during generation, raw The irregular bulky grain of forming shape, when the rate of addition of reactant 2 is 1/0.5S, the nano-TiO of generation₂Granule is thick, Size is uneven, and dispersibility is the highest.Slow down the rate of addition of reactant 2, and the particle size of product reduces, when rate of addition is During 1/4S, nano-TiO₂In fine particulate, disperse superposition the most layer by layer.

Embodiment 2

Being slowly added to 50ml dehydrated alcohol in 19ml butyl titanate, add 27ml diethanolamine under moderate-speed mixer, magnetic force stirs Mix 1.5h, as mixture 1.10ml deionized water is mixed homogeneously with 25ml dehydrated alcohol, as reactant 2.One Limit is stirred while being added dropwise in reactant 1 with the speed of 1/4S by reactant 2, regulates PH=4, stands after stirring 2h. Obtain water white transparency colloidal sol, after ageing 12h, become solid gel shape, by solid gel at Muffle kiln roasting 2.5h.Sintering temperature It is respectively 450 DEG C, 500 DEG C, 550 DEG C.The pure nano-TiO that Fig. 2 obtains at a temperature of being three kinds₂XRD figure spectrum.

As seen from the figure, in 2 θ=25.259 °, 37.921 °, 48.041 °, 53.920 °, 55.100 °, 62.677 °, 68.981 °, TiO when 75.037 °, under tri-kinds of Temperature Treatment of a, b, c₂All occur in that anatase nano-TiO₂Characteristic peak, correspond respectively to (101), (004), (200), (105), (211), (204), (116), (215) crystal face, illustrate 450 DEG C, 500 DEG C, Three kinds of TiO of preparation under 550 DEG C of sintering temperatures₂All contain anatase nano-TiO₂, wherein a, without other in addition to anatase peak in b Diffraction maximum, illustrates a, is all anatase nano-TiO in b₂, existing without Rutile Type, in the characteristic peak of a, b, in b, peak height is more Being prominent, peak type is the most sharp-pointed clear, and wanting at a temperature of the formation situation of anatase is compared with 450 DEG C under 500 DEG C of sintering temperatures is described Good.Except above-mentioned and a in c, the anatase characteristic peak that b occurs jointly, have also appeared 27.421 °, 36.060 °, 41.260 °, The characteristic peak of 44.041 °, 56.658 °, 63.979 ° etc. Rutile Types, illustrates when sintering temperature is 550 DEG C, a part of anatase Phase nano-TiO₂It is transformed into Rutile Type.

Embodiment 3

Zinc nitrate is dissolved in 10ml deionized water, adds after 25m1 dehydrated alcohol mix homogeneously as reactant 1.At 19ml Butyl titanate adds 50m1 dehydrated alcohol, adds 27ml diethanolamine while stirring as inhibitor, magnetic agitation 1.5h It is uniformly dispersed, as reactant 2.Stir while reactant 1 is added dropwise in reactant 2 with the speed of 1/4S, PH=4, stirs 2h.Ageing 12h formation gel, 450 DEG C, 500 DEG C, at Muffle kiln roasting 2.5h at 550 DEG C.Three Plant the nano-TiO of different ions doping under sintering temperature₂XRD figure compose such as Fig. 3 (Zn²⁺/TiO₂), Fig. 4 (Cu²⁺/TiO₂), Fig. 5 (La³⁺/TiO₂)。

As it is shown on figure 3, the Zn dopen Nano TiO of preparation under three kinds of sintering temperatures₂The XRD figure spectrum of a, b, c all occurs Anatase peak, illustrates 450 DEG C, 500 DEG C, under 550 DEG C of sintering temperatures, all creates Anatase in a, b, c.

Wherein a occurs without other diffraction maximums in addition to anatase peak, TiO in a is described₂It is all Anatase.Wherein diffraction in b Peak is anatase peak substantially, a rutile peak type occurs when 2 θ=50.022 °, in addition, without zinc oxide phases such as ZnO Diffraction maximum, Zn is described²⁺Substantially TiO is entered₂Lattice defines corresponding solid solution therewith, for the shape and width at peak, B relatively a peak type is more prominent, and between each peak, tendency is clear, and dopen Nano TiO is described₂Crystalline condition is good compared with a.Sintering temperature is There is Rutile Type peak to occur when 500 DEG C, relatively non-impurity-doped nano-TiO is described₂, Zn²⁺/TiO₂Changed to rutile by anatase Phase transition temperature reduces, and illustrates that ion doping can change phase transition temperature by changing lattice elements composition.

Wherein under 550 DEG C of sintering temperatures, c occurs a large amount of Rutile Type and ZnTiO₃Phase, along with the rising of sintering temperature, receives Rice TiO₂Being changed to Rutile Type by anatase, a portion is converted into ZnTiO₃, illustrate to control well sintering temperature, for Prepare dopen Nano TiO₂For most important.

Fig. 4 is at 450 DEG C, 500 DEG C, the Cu of preparation under 550 DEG C of sintering temperatures²⁺Dopen Nano TiO₂XRD figure, as figure Shown in, all occur in that anatase peak under three kinds of sintering temperatures, the Cu wherein obtained at 450 DEG C²⁺/TiO₂XRD figure in only go out Show anatase peak, the dopen Nano TiO prepared at a temperature of showing this₂For pure Anatase, obtain under 500 DEG C of sintering temperatures In the XRD figure spectrum of product b, rutile peak occur 2 θ=27.519 ° and 69.003 °, temperature raises, and anatase is to rutile Change.When sintering temperature is increased to 550 DEG C, the XRD figure spectrum of the product obtained such as schemes c, except there is nano-TiO in c₂ Outside Anatase peak, in 2 θ=27.382 °, 35.585 °, 53.800 ° occur in that TiO₂Diffraction maximum, it may be possible to due to Cu²⁺'s Doping, adds that sintering temperature persistently raises, causes granule to reunite on a large scale, the TiO of common phase occur₂。

Sintering temperature is from 450 DEG C to 500 DEG C, and temperature raises, and the diffraction peak intensity of product of roasting reduces, and half-peak breadth increases, may It is that temperature rising can make nano-TiO₂Degree of crystallinity declines or produces the phenomenon of crystal grain refinement, does not sends out after doping in XRD figure is composed The characteristic peak of existing Cu, illustrates to utilize sol-gal process to prepare dopen Nano TiO₂Cu uniform ion can be made to be dispersed in nano-TiO₂ Body mutually in.

With undoped p Cu²⁺Nano-TiO₂XRD figure spectrum compare, find doping Cu²⁺Nano-TiO₂XRD figure spectrum in Characteristic peak edge is width trend, and peak type is substantially clear not as undoped p product, and peak intensity increases, and doped metal ion pair is described Nano-TiO₂Crystal formation have significantly impact, nano-TiO may be promoted₂The transformation of crystal formation, produces lattice defect, causes diffraction There is widthization in various degree in characteristic peak.

Fig. 5 is La³⁺Ion-doped nano TiO₂Respectively at 450 DEG C, 500 DEG C, under 550 DEG C of sintering temperatures, obtain the XRD of product Collection of illustrative plates, as seen from the figure, under three kinds of different sintering temperatures, in 2 θ=25.275 °, 48.063 °, 53.893 °, 55.104 °, 62.730 ° Near all have anatase characteristic peak to occur, corresponding crystal face is 101,200,105,211,204, and occur without other characteristic peaks, say Bright at 450 DEG C, 500 DEG C, under 550 DEG C of sintering temperatures, all obtain dopen Nano TiO₂Anatase, without Rutile Type and gold Belong to oxide to occur mutually, La is described³⁺Doping can suppress nano-TiO₂The transformation of crystal formation.

Relatively 450 DEG C, 500 DEG C, the XRD figure of product under 550 DEG C of sintering temperatures, it can be seen that along with the rising of sintering temperature, The characteristic peak peak height of anatase reduces, diffraction peaks broadening, such as 450 DEG C, and 500 DEG C, in 2 θ=25.275 ° under 550 DEG C of sintering temperatures Neighbouring characteristic diffraction peak peak height is respectively 445, and 365,264, characteristic diffraction peak peak height time near 2 θ=48.129 ° is respectively 114,60,57.

In terms of the height of peak type, along with sintering temperature gradually rises from 450 DEG C to 550 DEG C, peak height is more and more lower, and crystalloid is described State raises along with temperature and tends to imperfect.From the point of view of peak width, along with the rising of sintering temperature, peak type definition reduces, peak type In width trend, show that crystal grain diameter diminishes along with temperature raises.

Embodiment 4

Preparing several doping respectively is 0.05%, 0.1%, 0.15%, and 0.2%, 0.3%, the Zn of 0.5%²⁺/TiO₂, Cu²⁺/ TiO₂, La³/TiO₂Powder remain standby (other conditions are identical, and rate of addition is 1/4s, PH=4, and sintering temperature is 450 DEG C, Time 2.5h).Choose methyl orange solution that concentration is 20mg/L as catalytic degradation object, the tubular type uviol lamp conduct of 50W Light source (pipe range 30cm, diameter 2.5cm).Weigh 0.5g photocatalyst and join that to fill 350ml 20mg/L methyl orange molten In the beaker of liquid, after ultrasonic 20min mix homogeneously, being placed in by beaker in the fully sheathed case placing uviol lamp, beaker mouth is away from uviol lamp Lower section 15cm, constantly carries out middling speed magnetic agitation in experiment, sample after 1h, takes the supernatant and survey extinction after being centrifuged separating Degree, the test wavelength of ultraviolet-visible spectrophotometer takes 465.2nm, and utilizes formula to calculate the degradation rate of methyl orange.

Fig. 6 is that doping is respectively 0.05%, the Zn of 0.1%, 0.15%, 0.2%, 0.3%, 0.5%²⁺/TiO₂, Cu²⁺/ TiO₂, La³⁺/TiO₂And pure nano-TiO₂The 1h degradation rate to methyl orange under uviol lamp.It will be appreciated from fig. 6 that dopen Nano TiO₂The purer nano-TiO of photocatalysis efficiency₂All there are raising in various degree, three kinds of metal doping nano TiO₂To methyl orange Degradation rate all improves with the increase of metal-doped amount, and when doping reaches certain value, photocatalytic activity is the highest, metal-doped After exceeding optimum doping amount, photocatalytic activity presents downward trend.Three metal ion species doping all have an optimum doping amount, its Middle Zn²⁺/TiO₂Middle Zn²⁺Optimum molar doping percentage ratio be 0.15%, Cu²⁺/TiO₂Middle Cu²⁺Optimum molar doping percentage Ratio is 0.2%, La³⁺/TiO₂Middle La³⁺For 0.15%, when doping is optimal proportion, photocatalysis effect is best.

Embodiment 5

Weigh pure nano-TiO respectively₂, 0.15%-Zn²⁺/TiO₂, 0.2%-Cu²⁺/TiO₂, 0.15%-La³⁺/TiO₂Each 0.5g Join in the beaker filling 350ml 20mg/L methyl orange solution, after ultrasonic 20min, beaker is placed in placement uviol lamp Fully sheathed case in, beaker mouth 15cm below uviol lamp, experiment constantly carries out middling speed magnetic agitation, takes one every 20min Secondary sample, takes the supernatant and surveys absorbance after centrifugation, the test wavelength of ultraviolet-visible spectrophotometer takes 465.2nm, and profit The degradation rate of different time sections methyl orange is calculated with formula.Pure nano-TiO₂And three kinds of metals under best metal ions dosage from Sub-dopen Nano TiO₂To the degradation rate of methyl orange over time, as shown in Figure 7.

As shown in Figure 7, degradation time is the longest, the highest to the degradation rate of methyl orange, and dopen Nano TiO₂Fall to methyl orange The purer nano-TiO of solution rate₂Raising in various degree all occurs, illustrates that metal-doped modification can improve nano-TiO₂Photocatalysis effect Rate, when degradation time is 2h, 0.15%-La³⁺/TiO₂The degradation rate of methyl orange be can reach 90%, 0.15%-Zn²⁺/TiO₂ For 89%, 0.2%-Cu²⁺/TiO₂Also reached 82%, catalytic effect is excellent.

Embodiment 6

Lanthanum (III) nitrate, zinc nitrate molar percentage are respectively 0.05%-0.1%, and 0.075%-0.075%, 0.1%-0.05%'s is several The combination of kind of metal nitrate is dissolved in 10ml deionized water respectively, adds after 25ml dehydrated alcohol mix homogeneously as reactant 1.In 19ml butyl titanate, add 50ml dehydrated alcohol, add 27ml diethanolamine while stirring as inhibitor, magnetic Power stirring 1.5h is uniformly dispersed, as reactant 2.Stir while reactant 1 is added dropwise over the speed of 1/4S In reactant 2, PH=4, stirs 2h.Ageing 12h forms gel, standby after Muffle kiln roasting 2.5h at 450 DEG C.

The La-Zn codope photocatalyst weighing 0.5g different proportion joins the burning filling 350ml 20mg/L methyl orange solution In Bei, after ultrasonic 20min mix homogeneously, being placed in by beaker in the fully sheathed case placing uviol lamp, beaker mouth is below uviol lamp 15 Cm, constantly carries out middling speed magnetic agitation in experiment, sample after 20min, takes the supernatant and survey absorbance after centrifugation, The test wavelength of ultraviolet-visible spectrophotometer takes 465.2nm, and utilizes formula to calculate the degradation rate of methyl orange.La-Zn is co-doped with Miscellaneous nano-TiO₂The degradation curve of methyl orange is shown in Fig. 8.

As shown in Figure 8, dopen Nano TiO during lanthanum-zinc co-doped₂To the degradation effect of methyl orange with lanthanum-zinc doping percentage ratio not Different together, when La doped amount is 0.05%, when zinc doping amount is 0.1%, after 2h, the degradation rate to methyl orange is 83%, relatively Both lists doping photocatalysis efficiency declined, illustrate that cooperative photocatalysis effect is also when lanthanum-zinc doping amount is 1: 2 Not embodying, when lanthanum-doping is 0.1%, and zinc doping amount is 0.05%, after 2h, the degradation rate to methyl orange reaches 95%, relatively List dopen Nano TiO₂Photocatalysis effect increase, illustrate with this codope ratio nano-TiO₂It is doped, permissible Suitable improves its photocatalysis effect to methyl orange solution, embodies the synergism of Metal Ions Co-doped.

In sum, above-mentioned metal doping nano TiO2 photocatalyst and preparation method thereof is illustrated by the present invention, but The invention is not restricted to this.It will be appreciated by those skilled in the art that without departing from the protection model described in claims of the present invention Can arbitrarily change and revise in the case of enclosing.

Claims (8)

1. prepare metal doping nano TiO for one kind₂The method of photocatalyst, comprises the following steps:

(1) butyl titanate is slowly added in dehydrated alcohol, adds diethanolamine and be uniformly dispersed as inhibitor, magnetic agitation, Standby as reactant 1；

(2) add the nitrate of metal ion in deionized water, add dehydrated alcohol mix homogeneously after fully dissolving, as instead Answer thing 2 standby；

(3) stir while reactant 2 is added dropwise in reactant 1 with certain speed, regulate PH=4, stir 2h, Ageing 12h forms gel, prepares metal-doped nano-TiO at Muffle kiln roasting 2.5h at 450～550 DEG C₂Photocatalyst.

Prepare metal doping nano TiO the most as claimed in claim 1₂The method of photocatalyst, it is characterised in that step (3) Described in reactant 2 is added drop-wise to the rate of addition in reactant 1 is 1/4S.

Prepare metal doping nano TiO the most as claimed in claim 1₂The method of photocatalyst, it is characterised in that step (3) Described in be 500 DEG C by gel in the temperature of Muffle kiln roasting.

4. a metal doping nano TiO₂Photocatalyst, it is characterised in that described photocatalyst is by arbitrary in claims 1 to 3 Method described in Xiang is made.

5. metal doping nano TiO as claimed in claim 4₂Photocatalyst, it is characterised in that described in be entrained in nano-TiO₂ In metal be Zn, its doping is 0.15%.

6. metal doping nano TiO as claimed in claim 4₂Photocatalyst, it is characterised in that described in be entrained in nano-TiO₂ In metal be Cu, its doping is 0.2%.

7. metal doping nano TiO as claimed in claim 4₂Photocatalyst, it is characterised in that described in be entrained in nano-TiO₂ In metal be La, its doping is 0.15%.

8. metal doping nano TiO as claimed in claim 4₂Photocatalyst, it is characterised in that described in be entrained in nano-TiO₂ In metal be La and Zn, the doping of described La is 0.1%, and the doping of Zn is 0.05%.