CN101318127B

CN101318127B - Composite titanium dioxide visible light catalyst and preparation method thereof

Info

Publication number: CN101318127B
Application number: CN2007100938587A
Authority: CN
Inventors: 吴瑛
Original assignee: SHANGHAI MU'ER BUILDING SCIENCE AND TECHNOLOGY Co Ltd
Current assignee: SHANGHAI MU'ER BUILDING SCIENCE AND TECHNOLOGY Co Ltd
Priority date: 2007-06-08
Filing date: 2007-06-08
Publication date: 2011-04-13
Anticipated expiration: 2027-06-08
Also published as: CN101318127A

Abstract

The invention relates to a composite titanium dioxide visible-light responsive photocatalyst and a preparation method thereof; the preparation method comprises the following steps: taking an ammonium metatungstate ((NH4)6H2W12O40.XH2O) solution; adding water according to the corrected mass ratio of 1:6-7 between a WO3 and water; adding a ferric nitrate (Fe(NO3)3.9H2O) according to the corrected mass ratio of 5-7: 1 between the WO3 and the ferric nitrate; dissolving and regulating a (Fe(NO3)3.9H2O) to obtain an impregnation liquid; adding a TiO2 powder (anatase type, BET specific surface is 80-150m<2>/g) in the impregnation liquid according to the corrected mass ratio of 1:6-7 between the WO3 and the TiO2 to mix; drying for 4-6 hours under 100 DEG C; roasting for 5 hours under 580-780 DEG C and obtaining the WO3-Fe2O3/TiO2 composite photocatalyst material; wherein, a primary crystallization grain diameter of the contained tungsten oxide is 10-80nm and the crystal structure is WO3; the crystal structure of the contained ferrite oxide is Alpha-Fe2O3.

Description

A kind of composite titanium dioxide visible light catalyst and preparation method thereof

Technical field

The present invention relates to a kind of composite titanium dioxide visible light catalyst and preparation method thereof, the visible light catalyst of gained can be used for the degraded of pollutant in the environment, belongs to field of nanometer material technology.

Technical background

Titanium dioxide (TiO ₂) be the semiconductor nano photochemical catalyst, have advantages such as chemical property is stable, catalytic activity is high, oxidability is strong, nontoxic, inexpensive, in fields such as air cleaning, sewage disposal, sterilization, the energy vast market prospect is arranged.At present, TiO ₂The bottleneck of photocatalytic applications is that its photoresponse scope is narrower, can only utilize the ultraviolet light of wavelength less than 387nm.And ultraviolet light only accounts for 4% of its energy of sunshine, and the sunshine medium ultraviolet light in the inlet chamber is almost nil.Visible light but accounts for 45% of solar energy.Therefore, the research and development that have the photochemical catalyst of greater activity under visible light have high economy and practical value.

The doping of metal ion is to realize nano-TiO ₂Under visible light, has one of effective means of photocatalytic activity.It is generally acknowledged, metal ion is incorporated into TiO ₂In the lattice, can in its forbidden band, introduce impurity energy level, reduce energy gap, after making electronics in the valence band accept the bigger optical excitation of wavelength, transit to impurity energy level earlier, by absorbing energy again, transit to conduction band by impurity energy level, reduce thus and be excited required energy, thereby realize making TiO ₂The spectral response range of photochemical catalyst moves to visible region.Between the several years in past, at TiO ₂Middle doping platinum group metal element Pt, Pd, Rh, Ru, Ir (the Japan Patent spy opens 2004-73910), transition metal Fe, Co, Ni, Cu, Zn, Ag, Cr, V, W, Sn (Chinese patent CN1799692A, 1583252A, 1792425A etc.), and lanthanide series La, Ce all multi-methods such as (Chinese patent CN1557539A) all have research paper or based on the patent documentation of result of study report.These achievements in research are at the TiO that narrows ₂Band gap, expansion TiO ₂Aspects such as photoresponse scope bigger progress is arranged.Particularly, platinum group metal metal ion mixing TiO wherein ₂Though the visible light-responded better performances of photochemical catalyst is even the platinum group metal metal that mixes seldom also causes this type of photochemical catalyst manufacturing cost too high.Mainly contain the complex centre that becomes electronics and hole because of the metal ion that mixes based on the visible light catalyst of doped with metal elements modification preparation in the problem that solves of still needing aspect the practical application and cause catalyst active decline under ultraviolet light, and degradation under the heat endurance.

Calendar year 2001, Japanese scholar R.Asahi goes up the alternative a spot of Lattice Oxygen of report nitrogen at " Science " can make TiO ₂Band gap narrow down, not reducing under the photoactive prerequisite of ultraviolet, make TiO ₂Have visible light activity, started nonmetal doping TiO ₂Research boom (Chinese patent CN1775359A, 1565721A, 1827225A, 1827709A, 1506154A, 1736584A etc.).From the practical application angle, the visible light catalyst of preparations such as the doped with non-metals elemental nitrogen problem that solves of still needing at present is how to improve crystallization-stable and quantum efficiency, and simplifies production technology, equipment.

The present inventor has developed a kind of composite titanium dioxide visible light catalyst and preparation method thereof by a large amount of experimental studies.The visible light catalyst of being invented has ultraviolet catalytic activity, the good stable of good visible light catalysis activity, excellence, and production technology is simple, cheap.

Summary of the invention

The objective of the invention is with the anatase titanium dioxide is matrix, a kind of method for preparing composite photocatalysis material of titanium dioxide is provided, by to the titanium deoxide catalyst modification, promptly change particle structure and surface nature, thereby enlarge the photoresponse scope, it is compound to improve quantum efficiency to suppress carrier, improves the stability of catalysis material.

Specific embodiment of the present invention and condition are: get ammonium metatungstate ((NH4) ₆H ₂W ₁₂O ₄₀XH ₂O) solution is by conversion WO ₃Add entry with the ratio of mass ratio 1:6～7 of water, again by conversion WO ₃Add ferric nitrate (Fe (NO with the ratio of the mass ratio 5～7:1 of ferric nitrate ₃) ₃9H ₂O) get maceration extract after dissolving is adjusted.Again by conversion WO ₃With TiO ₂The ratio of mass ratio 1:6～7 in maceration extract, add TiO ₂(Detitanium-ore-type, BET specific area were 80～150m2/g) to mix to powder, in 100 ℃ of dryings 4～6 hours.Then 580 ℃～780 ℃ roasting temperatures 5 hours.Promptly get WO ₃-Fe ₂O ₃/ TiO ₂Composite photocatalyst material, wherein, the primary crystallization particle diameter 10～80nm of the tungsten oxide that is contained, crystal structure are WO ₃The crystal structure of the ferriferous oxide that is contained is α-Fe ₂O ₃

The present invention has following advantage:

(1) WO that makes of the present invention ₃-Fe ₂O ₃/ TiO ₂Composite photocatalyst material is compared with the photochemical catalyst of undoped and single Doped Tungsten or iron, shows better photo-catalysis capability.The WO of the compound specific lattice structure of anatase titanium dioxide ₃And Fe ₂O ₃, be actually TiO ₂The modification of particle can promote the separation of charge and the charge movement of system, expansion TiO ₂Spectral response range.Gained photocatalyst granular size is even, and the photoresponse expanded range will be more widely used in fields such as the depollutions of environment.

(2) the present invention adopts the visible light catalyst preparation method of a kind of novelty of dipping and roasting combination, and preparation technology's equipment is simple, good reproducibility, and production cost is low.

Description of drawings

Fig. 1: WO ₃-Fe ₂O ₃/ TiO ₂The XRD figure of composite photocatalyst material can see that Detitanium-ore-type TiO is arranged from XRD figure ₂, WO ₃And α-Fe ₂O ₃Diffraction maximum, this explanation contains above-mentioned three kinds of materials in products obtained therefrom, has reached the preparation purpose.Maximum diffraction peak is TiO in 25.89 ° ₂The diffraction maximum of crystal face.Calculate according to the Scherrer formula, the particle diameter of this sample is 18nm.

Fig. 2: visible light catalytic acetaldehyde decomposition run is comparison diagram as a result

Fig. 2: ultraviolet catalytic acetaldehyde decomposition run is comparison diagram as a result

The specific embodiment

Embodiment 1

Commercially available ammonium metatungstate ((NH4) ₆H ₂W ₁₂O ₄₀XH ₂O) solution (conversion WO ₃Concentration 50wt%) 60g adds entry 200g, adds ferric nitrate (Fe (NO again ₃) ₃9H ₂O) get maceration extract after the 4.5g dissolving is adjusted.In maceration extract, add commercially available TiO again ₂Powder (Detitanium-ore-type, BET specific area are 85m2/g, Millennium Chemicals Inc. product) 200g mixed, in 100 ℃ of dryings 5 hours.Then 660 ℃ of roasting temperatures 5 hours.Promptly get WO ₃-Fe ₂O ₃/ TiO ₂Composite photocatalyst material.Measure according to XRD figure, contain WO in the embodiment 1 gained sample ₃Rhomboidal crystal, this WO ₃Particle diameter be 47nm.

Embodiment 2

In the foregoing description 1, change use amount (the mass ratio TiO of ammonium metatungstate and ferric nitrate ₂/ WO ₃/ Fe ₂O ₃=100/23/1.0; Mol ratio Fe/W=0.12), other conditions are constant.Make WO ₃-Fe ₂O ₃/ TiO ₂Composite photocatalyst material.Measure according to XRD figure, contain WO in the embodiment 2 gained samples ₃Rhomboidal crystal, this WO ₃Particle diameter be 38nm.

Embodiment 3

In the foregoing description 1, to change into 760 ℃ except that sintering temperature, other conditions are constant.Make WO ₃-Fe ₂O ₃/ TiO ₂Composite photocatalyst material.Measure according to XRD figure, contain WO in the embodiment 3 gained samples ₃Rhomboidal crystal, this WO ₃Particle diameter be 70nm.

Embodiment 4

In the foregoing description 1, change use amount (the mass ratio TiO of ammonium metatungstate and ferric nitrate ₂/ WO ₃/ Fe ₂O ₃=100/76/2.0; Mol ratio Fe/W=0.081), other conditions are constant.Make WO ₃-Fe ₂O ₃/ TiO ₂Composite photocatalyst material.Measure according to XRD figure, contain WO in the embodiment 4 gained samples ₃Rhomboidal crystal, this WO ₃Particle diameter be 38nm.

Reference example 1

In the foregoing description 1, except that not adding the ferric nitrate, other conditions are constant.Make WO ₃/ TiO ₂Composite photocatalyst material.Measure according to XRD figure, contain WO in the embodiment 3 gained samples ₃Rhomboidal crystal, this WO ₃Particle diameter be 23nm.

Comparative example 1

Only adopt commercially available WO ₃(Japanese Wako Pure Chemical Industries, Ltd. product).Use electron microscope observation, particle diameter reaches more than the 2000nm.

Comparative example 2

Only adopt with " embodiment 1 " in the TiO of use ₂Identical commercially available TiO ₂

Test example 1

Test film is madePrepared photochemical catalysts such as the foregoing description, reference example, comparative example are disperseed with ethanol respectively and, with 20g/m ²Consumption coat on the sheet glass of 140 * 110mm, be drying to obtain in 65 ℃.

Test methodTest film is placed respectively in the quartz glass system 5L reactor.Make its initial concentration reach 10ppm toward the interior acetaldehyde that injects of reactor, with light exposure experiment sheet.Change illumination condition and simulate the wave-length coverage of visible light, ultraviolet light respectively, establish the aldehydes gas concentration of spectrometry mensuration corresponding to irradiation time with gas phase.

Visible light catalytic performance test resultWith 2 of 4W fluorescent lamps, shine from the reactor outside to sheet on probation.Optical filter is affixed on the plane of illumination of reactor, makes the following all eliminations of ultraviolet ray of 420nm.The part test result as shown in Figure 2.

Ultraviolet catalytic performance test resultUse the 4W ultraviolet lamp, shine from the reactor outside to sheet on probation.Do not paste the optical filter film.The part test result as shown in Figure 4.

Claims

1. WO ₃-Fe ₂O ₃/ TiO ₂The preparation method of composite photocatalyst material is characterized in that comprising the steps:

(1) gets ammonium metatungstate solution, by conversion WO ₃Add entry with the ratio of the mass ratio 1: 6～7 of water, again by conversion WO ₃With the ratio of the mass ratio 5～7: 1 of ferric nitrate add the ferric nitrate dissolving after adjusting maceration extract;

(2) by conversion WO ₃With TiO ₂The ratio of mass ratio 1: 6～7 in maceration extract, adding crystalline phase is that anatase phase, BET specific area are 80～150m ²The titanium dioxide powder of/g mixes, in 100 ℃ of dryings 4～6 hours, then, 580 ℃～780 ℃ following roastings 5 hours.

2. a kind of composite titanium dioxide visible light catalyst that preparation method as claimed in claim 1 makes.

3. a kind of composite titanium dioxide visible light catalyst as claimed in claim 2 is characterized in that the tungsten oxide that is contained is WO ₃, primary crystallization particle diameter 10～80nm; The ferriferous oxide that is contained is α-Fe ₂O ₃