With the rapid development of industry, energy crisis and environment pollution become more and more serious. So how to save energy, how to control and deal with the enviroment pollution have been the most important thing nowadays. Among all the nano-photocatalytic materials, TiO2 become a most promising photocatalyst for its strong oxidation activity, stability and nontoxic. However, TiO2 has two main disadvantages: Firstly, low quantum yield and low photocatalytic activity. Secondly, large band gap energy (3.2ev) which is only active to ultraviolet light and thus waste energy source. Therefore, how to modify TiO2 in order to increase its photocatalytic activity and extend its range of photo-response spectrum is the key to further utilize in photocatalysis. In this paper, on the foundation of summarizing the development of the modification of nano-scaled TiO2 photocatalyst, the following aspects were mainly studied.1. In order to raise the photocatalytic activity, TiO2 was modified by doping Bi ions and Eu ions using combustion method. Doping mechanism was investigated and photodegradation experiments were made to find the best ion concentration of Bi and Eu. The results showed that ions doping can lead to lattice aberrance, thus reducing the recombination of electrion-cavity pairs and increasing quantum yield photocatalytic activities. The optimum doping concentration was different according to different doping ions. The optimum doping concentration of Bi ions is 3% while the optimum doping concentration of Eu ions is 0.5%. 2. Non-metal doping TiO2 have been studied in order to extend its range of photo-response spectrum and increase its photocatalytic activity. N-doped TiO2 and S-doped TiO2 photocatalysts were prepared using sol-gel method, sovolthermal method, respectively. The crystal structure, morphology, BET and absorbency were characterized by XRD, TEM, IR, BET, UV-vis spectrophotometer. Compared with pure TiO2, the grain size of the doping samples was smaller, the BET was larger. The absorbency increased greatly in the visible region because of the narrower of the band gap and the formation of doping level. The photocatalytic activity of photocatalysts was investigated to be high by degrading methylorange and the samples all have a good photocatalytic properity under visible-light irradiation.3. N-La co-doped TiO2 crystals were synthesized using sol-gel method. The effect of ion doping concentration to photocatalytic activity was investigated. Results show that the highest photodegradation was obtained at the optimum concentration of N5% and La 0.5%. Based on the study of N-La co-doped TiO2 nano-sized photocatalysis, N-La co-doped nano-sized photocatalysis films were synthesized. The effects of co-doping and film layers to lattice deformation and photocatalytic activity were studied. The results showed that La3+-doped samples with bigger ion radius could easily result in lattice deformation, and the replacing of Ti4+ with La3+ could form structure defect which was favour for hydroxylation of the surface grains to obviously heighten the photocatalytic activity of films. The films with four layers possessed the highest photodegradation ratio. The degradation ratio to methylorange and nitrobenze under UV irradiation for 3h was up to 73.98%, 96.29%, respectively. At the same time N doping could narrow the bang gap energy, thus result in the red-shift of absorption edge and increase the photocatalytic activity responding to visible light. The degradation ratios to methylorange and nitrobenze were 56.19% and 87.86% after irradiating under visible-light for 3h. It can be seen that N-La co-doping can not only extend the wavelength to visible light but also maintain good property under UV light, which exhibit new application foreground in the use of solar light.In a word, TiO2 photocatalysts were modified by different ions doping and many significative results were obtained including ion doping concentration, preparation methods, degradation efficiency, photocatalysis mechanics and so on. To a certain extent all the results had some innovation, and at the same time laid the foundation for the further study and practical application on nano-photocatalysts.

Nanostructure perovskite-type LaFeO₃, LaMnO₃ , LaCoO₃ and oxideα-Fe2O₃ were successfully synthesized by Stearic Acid Gel Combustion, where the stearic acid was used as chelating agent and fuel. The obtained samples were characterized by FTIR, XRD, SEM and BET techniques and their photocatalytic activities for TNT degradation were studied.The experimental results showed that LaFeO₃ andα-Fe2O₃ were directly obtained by combustion of stearic acid gel, but LaMnO₃ and LaCoO₃ were obtained by additio- nal calcinations treatment. The particle sizes of LaFeO₃, LaCoO₃ andα-Fe2O₃ are about 50nm, 40nm and 30nm, respectively, and their specific surface areas are 48.34m2/g, 22.23m2 /g and 63.4m2/g, respectively, which are higher than that recorded in literatures prepared by citrate acid or chemical coprecipitation method. But the particle diameter of LaMnO₃ is 0.5μm that is lager than those of LaFeO₃, LaCoO₃ andα-Fe2O₃.In addition, taking LaFeO₃, LaMnO₃ and LaCoO₃ as catalysts, we obtained the optimal reaction conditions. Adsorptive equilibrium time is about 30 minutes and the amounts of all used catalysts’amounts are 0.001mol. Compared with the other perovskite-type oxides （i.e. LaMnO₃ and LaCoO₃）, LaFeO₃ has the best photocatalytic activity which was further proved by UV-Vis DRS spectrogram.For LaFeO₃ catalyst, a variety of the factors that influenced in TNT degradation progress were investigated. Of all the initial concentrations of TNT, 20mg/L TNT could be rapidly degradaed in the alkaline conditions, the optimal reaction time was 60 minutes, and the photocatalytic reaction could be expressed as the first order kinetics. After reusing, LaFeO₃ still had good photocatalytic activity.A comparision of LaFeO₃ withα-Fe2O₃ showed that the oxygen and hydroxyl absorbed were probably the main active sites of LaFeO3 catalyst. Through the UV spectrogram, the possible pathway of TNT degradation was disscussed. First, methyl group was removed from TNT, then the nitro group which was difficult to oxide was reduced to amine group, finally, the aromatic compounds degraded into small organic molecules.

Photocatalysis TiO₂ has revealed very attractive application in the area of air pollution control,waste water treatment,bacillus resistance, pollution elimination,mist prevention and self-cleaning,still few studies were done under weak light source.In this study,N-or/and Sn-doped TiO₂ thin films（N/TiO₂,Sn/TiO₂,N/Sn/TiO₂）were prepared on glass slide by doping techniques based on sol-gel method,and their photocatalysic activity were evaluated by photooxidative degradation of formaldehyde using LED arrays as light source.The results showed that the photocatalytic activity of N/Sn/TiO₂ thin film was higher than that of undoped TiO₂ film,as well as that of N/TiO₂ and Sn/TiO₂ films.The crystal structure,surface properties and bandgap of these catalysts were investigated by X-ray photoelectron spectroscopy （XPS）,scanning electron microscopy（SEM）,X-ray diffraction（XRD）, Raman spectra（Raman）,infrared sectra（IR）,Ultraviolet-Visible spectrophotomery（UV-Vis）and other analytic methods.Based on the characterization of structure and surface properties,the mechanism of ion-doping and the reason of higher avtivity were studied.Parts of tin ions entered into the lattices of TiO₂ and substituted titanium ions,a few of nitrogen ions formed a new kind of N-Ti bond.The new energy levels caused by doping exist inside of band gap of TiO₂,which induces absorption at longer wavelength and more effective in disparation of photo-induced electron-hole pairs.As a result,N/Sn/TiO₂ thin film shew high photocatalysic acitivity in range of visible light.In this thesis,the degradation process of formaldehyde was monitored On-line by means of gas chromatography.On the basis of it we analyse the mechanism of gaseous photocatalytic oxidation of formaldehyde.

The thesis studied nanophase materials with their best doptant and the mechanics, the SiO₂-TiO₂, Fe2O3-TiO₂, CeO₂-TiO₂ nanophase photocatalysis was prepared by sol-gel method. The activity of non-uniform doped multiplayers was characterized by photocatalytic degradation of aqueous methyl orange under UV and visible light irradiation with self-made epuipument. The principle was also discussed with PN junction. Nano-film of N-doped TiO₂（N-TiO₂） were prepared at a certain temperature of 600℃in pipe-still heater.the film was studied with it’s visible light activity.The main test contents were as follows.TiO₂ was modified by Si, Ce, Fe with sol-gel method.Test got the relation between degradation rate and the best doping amount.In this study the correlation between crystal structure and photocatalysis of TiO₂ doped with different non-uniform multiplayers was studied. the average particle size was about 30nm, 14nm, 24nm. The results illustrate that the order of the FT, FF and TT films is FT>FF>TT , and in visible light the CeO₂-TiO₂ films have the better activity than Fe2O3-TiO₂ films.Nano-films of N-doped TiO₂（N-TiO₂） were prepared at a certain temperature of 600℃in pipe-still heater.The samples were modified by nitrogen doping in 3h, 4h, 5h respectively. The prepared films were characterized by XRD, XPS and UV-Vis absorbance spectra. The results showed that the crystal structure of N-TiO₂ was anatase, the average particle size was about 20nm and the optical absorption edge of film was significantly extended from 387nm to about 520nm that is in the visible-light range. N partly taken the place of O in TiO₂ crystal lattice and formed a new TiO₂-xNx crystal lattice. In the uv light,the order of activity among the flims is a>b>c. but in the visible light is c>b>a.

To improve photocatalytic ability of TiO₂ catalyst, N or Fe ions were involved in the crystal of TiO₂ via sol-gel method used urea or Fe（NO₃）₃·9H₂O as the doping which brought the visible-light sensitization of TiO₂ catalyst, and studied the different effect mechanism of nonmetal and metal doping. To evaluate the research of industrialisation application, the photooxidation of industrial waste was carried out in a series of experiments. The primary study was listed as following:（1） Calcined at 400℃in air atmosphere, as-prepared N/TiO₂ catalysts are entirely anatase phase. The surface of as-prepared N/TiO₂ catalyst is 109.1 m²·g^-1. average pore size is 69.9 nm, and the grain pathway is about 17.7 nm. Better surface structural improve the adsorption power of the pollutants, and the catalysts show high photocatalytic activity. The optimum N-content in N/TiO₂ is dertermined as 2.98 at.%. Moreover, the light absorption of as-prepared N/TiO₂ shows red-shift to 435 nm, the band gaps is determined to be 2.85 eV. The nitrogen atom enters into the TiO₂ lattice, occupies the position of oxygen atom, forms the bond of N-Ti-O, narrows the band gaps and makes as prepared N/TiO₂ shifted into the visible ragion.（2） In as-prepared Fe/TiO₂ catalysts, the optimum Fe-content is dertermined as 0.64 at.%. The Fe-doping not only depresses the grain growth of TiO₂ particles, but also reduces the phase transformation temperature of anatase to rutile. Calcined at 300℃in air atmosphere, as-prepared Fe/TiO₂ catalysts are anatase phase, the grain pathway is about 8 nm. The surface of as-prepared Fe/TiO₂ catalysts is 91.3 m²·g^-1, average pore size is 57.9 nm. The existence of Fe changes the surface structure of catalysts, which consequently reduces the chance of the recombination of the photoinduced electrons and holes. Calcined in air atmosphere at the temperature of 400℃, the light absorption of as-prepared Fe/TiO₂ shows red-shift to 459 nm, the band gaps reduces to 2.7 eV. The promoting effect of Fe-doping on the photocatalytic activity could be attributed to the formation of intermediate energy level that allows Fe/TiO₂ to be activated easily in the visible area.（3） In the multiphase photocatalysis reaction system, The application of photocatalysis is studied through the photodegradation of industrial waste diluted 1 times in oxygenated aqueous suspensions containing as-prepared TiO₂. The experiment result shows: after 180 minutes’ photoreaction, the degradation rate of TOC is higher than 80%. The concentration of TOC falling demonstrated the organic pollutants in the industrial waste were photodegraded. The total carbon in the system falling is due to the final outcome CO₂ departing from the reaction system, but TN has no change, this indicated the N element of the organic pollutants were not photodegraded to be N₂. The 10% degradation rate of Pb²⁺ in the industrial waste is owing to the adsorption ability of the as-prepared photocatalyst.

To improve photocatalytic ability of TiO₂ catalyst, N or Fe ions were involved in the crystal of TiO₂ via sol-gel method used urea or Fe（NO₃）₃·9H₂O as the doping which brought the visible-light sensitization of TiO₂ catalyst, and studied the different effect mechanism of nonmetal and metal doping. To evaluate the research of industrialisation application, the photooxidation of industrial waste was carried out in a series of experiments. The primary study was listed as following:（1） Calcined at 400℃in air atmosphere, as-prepared N/TiO₂ catalysts are entirely anatase phase. The surface of as-prepared N/TiO₂ catalyst is 109.1 m²·g^-1. average pore size is 69.9 nm, and the grain pathway is about 17.7 nm. Better surface structural improve the adsorption power of the pollutants, and the catalysts show high photocatalytic activity. The optimum N-content in N/TiO₂ is dertermined as 2.98 at.%. Moreover, the light absorption of as-prepared N/TiO₂ shows red-shift to 435 nm, the band gaps is determined to be 2.85 eV. The nitrogen atom enters into the TiO₂ lattice, occupies the position of oxygen atom, forms the bond of N-Ti-O, narrows the band gaps and makes as prepared N/TiO₂ shifted into the visible ragion.（2） In as-prepared Fe/TiO₂ catalysts, the optimum Fe-content is dertermined as 0.64 at.%. The Fe-doping not only depresses the grain growth of TiO₂ particles, but also reduces the phase transformation temperature of anatase to rutile. Calcined at 300℃in air atmosphere, as-prepared Fe/TiO₂ catalysts are anatase phase, the grain pathway is about 8 nm. The surface of as-prepared Fe/TiO₂ catalysts is 91.3 m²·g^-1, average pore size is 57.9 nm. The existence of Fe changes the surface structure of catalysts, which consequently reduces the chance of the recombination of the photoinduced electrons and holes. Calcined in air atmosphere at the temperature of 400℃, the light absorption of as-prepared Fe/TiO₂ shows red-shift to 459 nm, the band gaps reduces to 2.7 eV. The promoting effect of Fe-doping on the photocatalytic activity could be attributed to the formation of intermediate energy level that allows Fe/TiO₂ to be activated easily in the visible area.（3） In the multiphase photocatalysis reaction system, The application of photocatalysis is studied through the photodegradation of industrial waste diluted 1 times in oxygenated aqueous suspensions containing as-prepared TiO₂. The experiment result shows: after 180 minutes’ photoreaction, the degradation rate of TOC is higher than 80%. The concentration of TOC falling demonstrated the organic pollutants in the industrial waste were photodegraded. The total carbon in the system falling is due to the final outcome CO₂ departing from the reaction system, but TN has no change, this indicated the N element of the organic pollutants were not photodegraded to be N₂. The 10% degradation rate of Pb²⁺ in the industrial waste is owing to the adsorption ability of the as-prepared photocatalyst.

Because of the shortage of petroleum, people in printing and packaging turned around the research and appliance of oil-based ink from water-based ink. With the development of material science, the binder of water-based ink was improved that exploits its application area, which resulted in water-based ink wastewater discharge increasing greatly. As a new kind of printing and dyeing wastewater, water-based ink wastewater which outstanding characteristic is high chemical oxygen demand, high chroma and difficultly biodegraded is still part of dyeing and finishing of textile industry. Once the wastewater enters water body, it will greatly pollute water environment that will seriously threaten human production and life and the natural ecological balance, which has attracted wide attention in the social life. In order to the request of improving environmental quality, the government drawn strick discharge standard of water-based ink wastewater, and developing economical, high efficient treatment of this wastewater has become the emphasis and hotspot of water treatment technology.This paper taking high concentration water-based ink wastewater from a corporation in Xi’an as the researching object, studied on its treatment technology via the preparation of experimental material, degradation of methylene blue–simulating water-based ink wastewater and the treatment of water-based ink wasterwater. This thesis aimed at finding out the optimum conditions of photocatalysis degrading methylene blue by Kaolin ultrafine zeolite composite photocatalyst, and establishing the economical treatment technology on water-based ink wastewater by acid precipitation, chemical flocculation, photocatalysis and biological method.The main findings were as following:(1) In allusion to the characteristic of water-based ink wastewater, we have choosed reasonable determining quota and the standard manual method, filtrated methylene blue as the simulant water-based ink wastewater and prepared Kaolin ultrafine zeolite composite photocatalyst.(2) Using L25(56) orthogonal experiment, we have discussed the effect of the light source, pH, reaction time and the concentration of H2O2, photocatalyst and methylene blue on photodegrading methylene blue. The result showed that the optimum conditions were 2 000 mg/L, 500 mg/L and 80 mg/L respectively being as the concentration of H2O2, photocatalyst and methylene blue, pH=10.00, ultraviolet disinfection lamp (20 W) irradiating 240 minutes, then the decoloration rate, the chroma and pH for methylene blue were 99.46%, 17.37, 7.58 respectively, which reached theⅠd ischarge standard of water pollutionts for dyeing and finishing of textile industry(GB 4287–92).(3) Through acid precipitation, chemical flocculation, photocatalysis and biological method, the economical treatment technology on water-based ink wastewater was established: the optimum pH value and standing time of acid precipitation was 4.36 and 12 hours respectively, the residence time of supernatant in the hydrolysis-acidification pool was 24 hours, then entering the sequencing batch reactor, the optimum dose of activated sludge was by SV30=25%, the temperature was 20±1℃,the dissolved oxygen was 9.07 mg/L and the aeration time was 8 hours, which could stablely operate half a month at least. The effluent of SBR: the pH value was between 6 and 9, the chroma was less than 40(dilution multiple method: the initial chroma was106 375), the BOD5 was less than 25 mg/L, which reached theⅠdischarge standard of water pollutionts for dyeing and finishing of textile industry. The CODcr was less than 500 mg/L (the initial was 31 040 mg/L), which was close to theⅡdischarge standard of water pollutionts for dyeing and finishing of textile industry. The SS and turbidity of supernatant were not detected. The optimum condition not only saved energy sources of traditional biological method but also the indexs of effluent reached or exceeded theⅢd ischarge standard of water pollutionts for dyeing and finishing of textile industry.

Exploiting and researching visible-light-induced photocatalyzer TiO₂ is the key point of the industrialization of photocatalysis. Meanwhile, it’s one of the challenging subjects in reducing the indoor-energy consumption. In this paper, review was first made on machenism, and then TiO₂ films was conceived to be modified by means of doping, in order to acquire solar-controlled and easy-cleaning films.In order to improve the photocatalytic activity and make full use of the solar rays, as well as considering its industrialization, the nano TiO₂ films and S doped TiO_2-xS_x films were synthesized by APCVD method using TTIP as a precursor on two kinds of substrates. The deposition process imitated the float glass line.This paper systematically analyzed the relations between the technical parameters such as substrate temperature, substrate moving rate and substrate coatings and the crystallization and surface morphology, optical properties, photocalysis and hydrophilicity of TiO₂ films. Cross experiments method was applied for synthetically analyzing the great effect of the factors. Considering the the integrative properties of the films, a suit of optimized technical parameters was acquired by range analysis. Underlay films was used to prevent alkali metal ions from separating out. When the substrate which has a basic coating moved in 6m/min at the temperature of 600℃, the films behaved well in photo-induced decomposition with best density and crystallization, as well as the solar controlled effect in some extent.This paper contrasted the photocatalytic activity and optical properties of TiO₂ films with those of TiO_2-xS_x films. In the visible waveband, the transmittance of TiO_2-xS_x films was as good as TiO₂ films. The slope of linear part of transmittance curve increased with increasing S doping. In other words, the optical absorption-edge obviously shifted to the longer wavelength in some extent. While the reflectivity of TiO_2-xS_x films behaved worse than undoped samples. The refractive index of all the doped samples was lower than the undoped. Only the 10% doped sample got a peak in the visible waveband which represents a high absorbtion to visible light. TiO_2-xS_x films prepared by APCVD played well in easy-cleaning at a certain extent. For a lack of raw material in Si films manufacture, TiO_2-xS_x films is expected to be the substitute with easy-cleaning, solar-controlling and commercial prospect.

Photocatalysis of semiconductors is a widely investigated subject during the past 30 years.Among them,titanium dioxide is the most latent material for its chemical stability,wearibility,low cost and innocuity.At the same time,some of the low-E thin films like AZO is photo-catalytic themselves.However,for their instability,they are not suitable to be photo-catalytic agent directly.Coupling these low-e films with TiO₂ thin films could prevent corrosion of the AZO and enhance photo-catalytic performance of the whole composite films.But simply coupled films doesn’t make full use of the light-induced charges in the under-layer of the coupled films.This article determine to make the AZO under-layer partly exposed by different ways, and achieve an enhanced photo-catalytic performance.AZO films,TiO₂ films and their composite films are prepared by magnetron sputtering,and pretreated by PVA solution,or post-treated by annealing and plasma.Microstructure are investigated by XRD,SEM and optical microscopy;electrical performance are measured by FOUR-POINT PROBE METER;optical performance is investigated by UV-vis Spectrometer;and photo-catalytic performance is measured by the degradation of Rodanmine B under UV light in 2 hours.AZO films prepared by sputtering exhibit a relatively low resistance.After being treated by different plasma,the surface morphology behaves huge changes.Especially, N and Ar plasma treatment cause holes of different size and shape on the surface of the films.This phenomenon may be used to realize AZO under-layer exposure.AZO under-layer exposed composite films are obtained by pre-spraying of PVA solution.Such films turn out superior photo-catalytic performance to the simply composite films.Dip Such PVA treated composite films into AgNO₃ and Na₂S solution respectively,irradiate them with UV light for 45minutes’,and then, precipitation of Ag and S appears on the exposed AZO part.That means,Magnetron sputtering AZO films are more active than TiO₂ films.But Ag and S has a different distribution.The amount of Ag precipitation has a ascendant grads toward the centre, but the amount of S precipitation has a ascendant grads outward the centre.As indicated by the following equations,Ag⁺+e^-→Ag↓and S^2-+2h⁺→S↓,Ag distribution exhibits e^- distribution and S distribution exhibits h⁺ distribution.That means light excitated h⁺ is drifted to the AZO side,and e^- to the TiO₂ side.Take the size of S precipitation enrichment into consideration,we anticipate the Optimum size of the exposed area is 10 micron.Ag⁺,S^2-are proved to be developer of the distribution of e^-,h⁺ respectively.Annealed AZO-TiO₂ composite films exhibit better photocatalysis even than the PVA treated ones.Higher crystallization of AZO under-layer is proved by XRD,and exposed AZO under-layer is also confirmed in such films.

The strong metal-support interaction has very important effect on the photocatalytic activity as the system has special electron configuration and geometric structure. So the study of the strong metal-support interaction possesses practical and theoretical interest. With the combination of X-ray photoelectron spectroscopy （XPS） and Ar⁺ sputtering technique, we investigated the strong metal-support interaction between Pt and TiO₂ in different atmosphere, and its effect on the photocatalytic activity of C₃H₆ was studied.When Pt/TiO₂ films were treated by inert N₂ at 400℃, the Ar⁺ sputtering results indicated that with the increase of sputtering time, the binding energy of Pt 4f moved to the higher direction. The higher binding energy of Pt species occurred and at the same time Pt atomic conc. versus sputtering time increased first and then decreased which indicated that two strong interactions occurred: （1） Encapsulation, i.e, The encapsulation of Pt0 particles by Ti_xO_y which was formed by the spillover of oxygen atoms from the surface of TiO₂ during the high-temperature treatment of Pt/TiO₂ in inert N₂ gas. （2） Thermal diffusion: Pt0 atoms can diffuse into TiO₂ lattice and be oxidized to Pt²⁺ to substitute for Ti atoms. The experimental results showed that the encapsulation of Pt0 particles by Ti_xO_y and the increase of Pt0 particle size were the reasons for the obvious decrease of C₃H₆ photocatalytic activity.When Pt/TiO₂ films were treated in reducing H₂ at 400℃, the Ar⁺ sputtering results indicated that with the increase of sputtering time, the binding energy of Pt 4f moved to the lower direction. The lower binding energy of Pt species occurred and at the same time Pt atomic conc. versus sputtering time increased first and then decreased which indicated that there were two strong interactions occurred （But they were different from those in inert N₂ atmosphere）: （1） Encapsulation, i.e, during the high-temperature treatment of Pt/TiO₂ in reducing H₂ gas, the encapsulation of Pt0 particles by Ti_xO_y which was formed by the spillover of oxygen atoms from the surface of TiO₂. （2） Thermal diffusion: Pt0 atoms can diffuse into TiO₂ lattice and be reduced to Pt- to substitute for O atoms. When Pt/TiO₂ was treated in reducing H₂ at low-temperature 200℃, the PtO layer on the surface of the untreated catalyst transformed to be Pt0 which made the photocatalytic activity increased. But when Pt/TiO₂ was treated in reducing H₂ at high temperature, the encapsulation and the increase of Pt0 particle size resulted in the decrease of C₃H₆ photocatalytic activity.In the dissertation the structure and photocatalytic activity of the TiO₂ prepared from the treatment of nanotubed titanic acid （NTA） in CO was investigated. The results showed that the TiO₂ obtained by CO treatment of NTA were inert in photocatalytic activity under visible-light irradiation, but active under UV-light irradiation, while the UV–light photocatalytic activity decreased with the increase of the treating temperature in CO atmosphere. The characterization results showed that when NTA was treated in CO at high temperature, the carbon doping in product TiO₂ did not appear,only carbon deposition on TiO₂ appeared; the BET areas of the products decreased markedly with the increase of treating temperature; The transformation temperature from anatase to rutile for TiO₂ obtained by CO treatment was much lower than that obtained by air treatment. These were the reasons for the decrease of UV-light photocatalytic activity.