Photodegradation catalyst screening by combinatorial methodology

In this work, a combinatorial methodology was developed for photodegradation catalyst screening. A fluorescence imaging detection system was designed for high throughput analysis, 1,6-hexamethylenediamine was used as the probe molecule for catalyst testing. The photodegradation activity of catalysts was evaluated by 1,6-hexamethylenediamine consumption during the photodegradation reaction. The methodology could provide reliable results. We found that pure TiO₂, ZrO₂, Nb₂O₅, MoO₃, and WO₃ did not show much activity for 1,6-hexamethylenediamine photodegradation under visible light. TiO₂ catalysts doped with different metal ions were tested. When TiO₂ was doped with Ta₂O₅, Nb₂O₅, V₂O₅, MoO₃, or WO₃, higher activity for photodegradation was observed. The doping of La³⁺, Ba²⁺, and Br⁻ to TiO₂ did not improve the catalytic activities. When doping TiO₂ with Mn²⁺, Cl⁻, Al³⁺, Cu²⁺, Fe³⁺, Na⁺, Mg²⁺, Li⁺, F⁻, Co²⁺, or K⁺, catalytic activity was lower than that of pure TiO₂. After elaborate catalysts screening, we discovered new catalysts, such as 50–70% TiO₂/0–20% WO₃/20–40% VO_2.5 and 20–30% TiO₂/30–50% MoO₃/40–60% VO_2.5 as well as 30% WO₃/20% ZrO₂/50% NbO_2.5 (synthesized from ZrCl₄, NbCl₅, and (NH₄)₅H₅[H₂(WO₄)₆]·H₂O in ethanol solution or suspension) and 60–70% WO₃/Nb₂O₅ (synthesized from WCl₆ and NbCl₅ in ethanol solution). We observed that the catalytic activity is sensitive to preparation methods and catalyst specific surface areas. When P123 (HO(CH₂CH₂O)₂₀(CH₂CH(CH₃)O)₇₀(CH₂CH₂O)₂₀H, designated EO₂₀PO₇₀EO₂₀) was used as template to synthesize mesoporous materials, the mesoporous catalysts showed higher activity than regular catalytic materials.     

Characterization and photocatalytic activity of transition-metal-supported surface bond-conjugated TiO2/SiO2

TM/TiO₂/SiO₂ photocatalysts were prepared by the photodeposition method using transition metal salts (TM=Fe³⁺, Co²⁺, Ni²⁺ and Cu²⁺) as precursors and the surface bond-conjugated TiO₂/SiO₂ as supporter in N₂ atmosphere, and were characterized by XRD, XPS, UV-Vis diffuse reflection and zeta-potential. Their photocatalytic activities were evaluated using reactive brilliant red K-2G (K-2G) and cationic blue X-GRL (CBX) showing different adsorption behavior on the oxides. Fe, Cu supported TiO₂/SiO₂ can efficiently extend the light absorption to the visible region. XPS analysis verified that the introduction of transition metal lead to the changes of the electronic environmental of Ti cations and the zeta-potential of oxides. As a result, K-2G has higher adsorption on the modified TiO₂/SiO₂ than that on the baked one, while the adsorption of CBX has a little change on the both oxides. At the same time, for the photodegradation of K-2G, Fe³⁺, Co²⁺, Ni²⁺-modified catalysts show that their photoactivities are 3.3–2.2 times higher than the bare one. On the contrast, all transition-metal-supported catalysts have no significant activity improvement except that Fe/TiO₂/SiO₂ shows 1.68 times higher activity for the photodegradation of CBX. The results indicate that the photoactivity could be increased in photodegradation of dyes by changing the performances of adsorption to dyes and absorption to light of photocatalyst.     

Efficient synthesis of titania nanotubes and enhanced photoresponse of Pt decorated TiO2 for water splitting

We investigated the effect of HMT (hexamethylenetetraamine) on the anodic growth of TiO₂ nanotube arrays. The tube length increases to 4.3 μm with HMT concentration increasing to 0.04 mol·L^-1. Adsorption of HMT on the TiO₂ surface is shown to markedly decrease the chemical dissolution rate of tube mouth, resulting in longer nanotube length. Furthermore, Pt nanoparticles were successfully deposited on the surface of TiO₂ nanotubes by ac electrodeposition method. The TiO₂/Pt composites were characterized by field emission scanning electron microscope (FESEM), X-ray photoelectron spectra (XPS), and photoelectrochemistry. An enhancement in photocurrent density has been achieved upon modification of TiO₂ nanotubes with Pt nanoparticles.     

冬瓜基含TiO2炭气凝胶的制备、表征及其光催化性能

以冬瓜和钛酸四丁酯为原料,采用水热法和冷冻干燥法成功制备出含TiO₂炭气凝胶（WTCA）,研究了其对罗丹明B废水的光催化降解性能,并考察了水中常见无机盐离子对其光催化效果的影响。利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、拉曼光谱仪（Raman）和荧光光谱仪（FL）等对样品结构和性能进行了表征。XRD、Raman和EDS分析表明复合气凝胶中含有锐钛矿TiO₂和碳元素;SEM和TEM分析表明TiO₂纳米颗粒均匀地负载在具有多级孔洞结构的炭气凝胶的骨架表面;含TiO₂炭气凝胶的光催化活性明显高于纯TiO₂,当负载量达30%时,其对罗丹明B的光催化降解效率最高（降解率达96.11%）。此外,无机盐阴离子对复合气凝胶的光催化效果有一定的抑制作用（CO₃^2- > SO₄^2- > Cl^- > NO₃^-）,而无机盐阳离子Na⁺、K⁺、Ca²⁺和Mg²⁺的抑制作用不明显。     

Study of special cases where the enhanced photocatalytic activities of Pt/TiO2 vanish under low light intensity

Surface platinized TiO₂ (Pt/TiO₂) has been widely used and investigated but their properties are yet to be understood fully. Although it is known that the Pt effects depend on many experimental parameters and the kind of substrates, this study newly finds that the Pt effects could be also influenced by the light intensity. As for the photocatalytic degradation of trichloroethylene (TCE), the Pt effect was positive at high light intensity but was negative at low light intensity. A similar behavior was also observed in the photocurrent collection in the Pt/TiO₂ suspension with polyoxometalate (POM: PW₁₂O₄₀³⁻) used as an electron shuttle. The photocurrent collection in the Pt/TiO₂ suspension was less efficient than in TiO₂ suspension when the light intensity was low. Such abnormal light intensity-dependent behaviors were not observed in the photocatalytic degradation of dichloroacetate on Pt/TiO₂ and the Fe³⁺-mediated photocurrent collection in the Pt/TiO₂ suspension. It is proposed that the photochemical interactions between the Pt surface and reactive intermediates (TCE radical anions and reduced POM anions) induce a null reaction favorably at low light intensity condition.     

Influence of operating parameters on photocatalytic degradation of phenol in UV/TiO2 process

The use of hydrogen peroxide (H₂O₂) for improved photocatalytic degradation of phenol in aqueous suspension of commercial TiO₂ powders (Degussa P-25) was investigated. Photodegradation was compared using direct photolysis (UV alone), H₂O₂/UV, TiO₂/UV, and H₂O₂/TiO₂/UV processes in a batch reactor with high-pressure mercury lamp irradiation. The effects of operating parameters such as catalyst dosage, light intensity, pH of the solution, the initial phenol, and H₂O₂ concentrations on photodegradation process were examined. It was shown that photodegradation using H₂O₂/TiO₂/UV process was much more effective than using either H₂O₂/UV or TiO₂/UV process. The effect of the initial phenol concentration on TOC removal was also studied, demonstrating that more than 8 h was required to completely mineralize phenol into water and carbon dioxide. For all the four oxidation processes studied, photodegradation followed the first-order kinetics. The apparent rate constants with 400-W UV ranged from 5.0 × 10⁻⁴ min⁻¹ by direct photolysis to 1.4 × 10⁻² min⁻¹ using H₂O₂/TiO₂/UV process. The role of H₂O₂ on such enhanced photodegradation of phenol in aqueous solution was finally discussed.     

The CO–H2 and CO–H2O reactions over TiO2 nanotubes filled with Pt metal nanoparticles

We have investigated the catalytic behavior of Pt encapsulated TiO₂ nanotubes for the water gas shift reaction as well as the hydrogenation of CO. Pt–TiO₂ nanotube catalysts were prepared by employing fine fiber shaped crystals of [Pt(NH₃)₄](HCO₃)₂ complex as a structure determining template material. The turnover frequencies (TOF) of these nanotube catalysts were more than one order of magnitude larger than conventional impregnation Pt/TiO₂ catalysts, and the selectivity for methanol in CO–H₂ reaction was extraordinary high compared to the impregnation catalysts. The XPS and XRD analyses of the nanotubes revealed characteristic electronic state of reduced TiO₂ (Ti³⁺ in rutile structure) with zerovalent Pt even after the calcination at 773 K. In WGS reaction, electron rich Ti³⁺ on the nanotube wall may play an important role to activate water molecules for the oxidation of CO. In CO–H₂ reaction, similar promotion effect of Ti³⁺ species may be operating for selective methanol formation by supplying active OH(a).     

A comparative study of TiO2 supported noble metal catalysts for the oxidation of formaldehyde at room temperature

The TiO₂ supported noble metal (Au, Rh, Pd and Pt) catalysts were prepared by impregnation method and characterized by means of X-ray diffraction (XRD) and BET. These catalysts were tested for the catalytic oxidation of formaldehyde (HCHO). It was found that the order of activity was Pt/TiO₂  Rh/TiO₂ > Pd/TiO₂ > Au/TiO₂  TiO₂. HCHO could be completely oxidized into CO₂ and H₂O over Pt/TiO₂ in a gas hourly space velocity (GHSV) of 50,000 h⁻¹ even at room temperature. In contrast, the other catalysts were much less effective for HCHO oxidation at the same reaction conditions. HCHO conversion to CO₂ was only 20% over the Rh/TiO₂ at 20 °C. The Pd/TiO₂ and Au/TiO₂ showed no activities for HCHO oxidation at 20 °C. The different activities of the noble metals for HCHO oxidation were studied with respect to the behavior of adsorbed species on the catalysts surface at room temperature using in situ DRIFTS. The results show that the activities of the TiO₂ supported Pt, Rh, Pd and Au catalysts for HCHO oxidation are closely related to their capacities for the formation of formate species and the formate decomposition into CO species. Based on in situ DRIFTS studies, a simplified reaction scheme of HCHO oxidation was also proposed.     

Catalytic oxidation of low concentration formaldehyde over Pt/TiO2 catalyst

Formaldehyde(HCHO) is an important indoor pollutant.Catalytic oxidize low concentration HCHO is an effective way to eliminate indoor pollution.In this study,a series of Pt/TiO_2 catalysts are prepared by impregnation and reduced by NaBH_4.The effects of loading amount of Pt and cry stal type of TiO_2 on the physical and chemical properties and the catalytic performance in HCHO oxidation reaction are investigated.The results show that the quantity of active site and the oxygen vacancy of catalysts increa sed with increasing Pt content,which is beneficial to promote the further performance of catalysts.Nevertheless,with the further rises of Pt content,the specific surface area further decreases,and the proportion of Pt~(2+) species on the catalyst surface which is significant to catalytic properties also decreases,causing catalytic performance decreases.Compared with the catalyst supporting on rutile,the Pt/α-TiO_2 catalyst supporting on anatase has larger specific surface area,more Pt~(2+) phase and easier to form oxygen vacancy in the support,which cause better catalytic performance.The catalyst with Pt content of0.1 wt% and supported by anatase TiO_2 has the best catalytic performance.The HCHO conversion efficiency reaches 98% and 100% at 50℃ and 100 ℃, and the stabilization time is longer than 140 h.     

Preparation of Au/TiO2 catalysts from Au(I)–thiosulfate complex and study of their photocatalytic activity for the degradation of methyl orange

Gold loaded on TiO₂ (Au/TiO₂) catalysts were prepared using Au(I)–thiosulfate complex (Au(S₂O₃)₂³⁻) as the gold precursor for the first time. The samples were characterized by UV–vis diffuse reflectance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic absorption flame emission spectroscopy (AAS), and X-ray photoelectron spectroscopy (XPS) methods. Using Au(S₂O₃)₂³⁻ as gold precursor, ultra-fine gold nanoparticles with a highly disperse state can be successfully formed on the surface of TiO₂. The diameter of Au nanoparticles increases from 1.8 to 3.0 nm with increasing the nominal Au loading from 1% to 8%. The photocatalytic activity of Au/TiO₂ catalysts was evaluated from the analysis of the photodegradation of methyl orange (MO). With the similar Au loading, the catalysts prepared with Au(S₂O₃)₂³⁻ precursor exhibit higher photocatalytic activity for methyl orange degradation when compared with the Au/TiO₂ catalysts prepared with the methods of deposition–precipitation (DP) and impregnation (IMP). The preparation method has decisive influences on the morphology, size and number of Au nanoparticles loaded on the surface of TiO₂ and further affects the photocatalytic activity of the obtained catalysts.     

Surface nano-aggregation and photocatalytic activity of TiO2 on H-type activated carbons

The main objective of this work is to detect any associative or synergistic effects between TiO₂ and activated carbon in 4-chlorophenol photodegradation. Different activated carbons (AC) were prepared from Tabebuia pentaphyla wood by means of physical activation with CO₂ or by extensive carbonization under N₂ flow at temperatures from 450 °C up to 1000 °C during 1 h. Results indicate a clear correlation between photocatalytic activities of titania with texture and surface chemistry of AC. Kinetic results of 4-chlorophenol photodegradation indicate that for most of mixed TiO₂ and AC solids a synergistic effect between both solids is observed. Surface nano-aggregation of TiO₂ on AC was observed by scanning electronic microscopy and dispersion of TiO₂ nanoparticles was improved as a function of more basic surface pH of AC. In conclusion, an increase of electronic density in carbon support clearly introduces an enhancement in titania's photoactivity for 4CP photodegradation. This beneficial effect indicates that it is possible to obtain clean water in a much shorter period of time by employing some selected AC in conjunction with TiO₂.     

活性炭纤维负载Pr3+:Y2SiO5/TiO2复合材料的制备与性能

为了提高纳米TiO₂对太阳光的利用率和实现光催化剂的回收再利用,采用溶胶-凝胶法将上转换荧光材料与纳米TiO₂复合,通过负载于活性炭纤维（ACF）表面制备了Pr³⁺：Y₂SiO₅/TiO₂/ACF复合材料。运用XRD、FT-IR、SEM、FS、UV-vis DRS等对材料的结构及性能进行了综合表征,并以亚甲基蓝为模拟污染物评价复合材料的可见光催化活性,考察了材料制备过程中煅烧温度、负载次数等制备条件对复合材料可见光下催化性能的影响。结果表明,在浸渍2次、800℃煅烧的制备条件下,复合材料中TiO₂为锐钛矿相（占34.1%）与金红石相（占65.9%）的混合相,亚甲基蓝（15 mg·L^-1）12 h内去除率高达93.8%,反应符合拟一级动力学,反应速率常数为0.2471 h^-1,回收再生利用4次后去除率仍保持在75%以上。     

Pt/TiO2/ZSM-5催化剂的制备及其催化转化正丁烷

采用溶胶-凝胶法和等体积浸渍法,分别对ZSM-5分子筛进行TiO₂改性和Pt负载,获得了具有脱氢-裂解双功能的Pt/TiO₂/ZSM-5催化剂,采用XRD、N₂吸附-脱附、TEM、XPS和NH₃-TPD对样品的晶体结构,孔结构、形貌、活性金属价态和酸性质等进行了表征,并研究了正丁烷在此催化剂上催化转化制备低碳烯烃的反应规律。研究结果表明,TiO₂的引入,一方面使得改性后的ZSM-5分子筛获得了额外的酸性中心,特别是强酸性位含量的增加,有助于促进正丁烷的活化;另一方面Pt与TiO₂之间存在“金属-载体”强相互作用（SMSI）,在H₂还原气氛下,Pt能够促进TiO₂的还原,生成Ti³⁺物种,而Ti³⁺的存在增加了Pt周围的电荷密度,降低了Pt对低碳烯烃（C₂⁼～C₃⁼）的吸附能力,抑制了深度脱氢和生焦反应,从而提高双功能催化剂对烯烃的选择性。当H₂还原温度为450℃时,Pt/10TiO₂/ZSM-5催化剂在625℃下的正丁烷转化率为76.1%,低碳烯烃（C₂⁼～C₃⁼）收率为50.9%,分别比Pt/ZSM-5催化剂提高了16.7%和12.6%。     

Dye sensitized artificial photosynthesis in the gas phase over thin and thick TiO2 films under UV and visible light irradiation

Perylene diimide based organic sensitizers capable of electron generation under illumination were used to initiate gas phase photo reduction reactions on TiO₂ thin and thick film surfaces. For comparison [Ru(Bpy)₃]²⁺ dye sensitizers were also studied. The photo reduction of CO₂ was carried out under static conditions in the gas phase. TiO₂ films were coated on hollow glass beads via a sol–gel procedure. Pt was incorporated on the films either by adding the precursor salt in the sol, Pt(in), or by wet impregnation of calcined film with an aqueous solution of the precursor salt, Pt(on). Organic sensitizers were incorporated on the films by wet impregnation of the film from an aqueous solution. Under UV illumination, the methane yields of platinized TiO₂ thin films decreased in the following order: Pt(on)·TiO₂ > Pt(in)·TiO₂ > TiO₂. The presence of organic sensitizers inhibited the catalytic activity of pure and platinized TiO₂ thick films under UV illumination. The relative enhancement of the reaction yields in the presence of the organic sensitizer under visible light illumination depended on the presence of Pt as well as the incorporation method of Pt in the TiO₂ structure. The reaction yields were better when Pt was impregnated on the TiO₂ film than when Pt was incorporated in the Ti sol. On the other hand, pure or platinized TiO₂ under visible light illumination was totally inactive indicating the role of the organic dye in generating catalytically active electrons under visible light.     

The effect of platinum and silver deposits in the photocatalytic oxidation of resorcinol

The effects of platinum (Pt) and silver (Ag) metallisation in the photocatalytic oxidation of resorcinol at pH 3 ± 0.5 have been investigated. The photocatalytic degradation of resorcinol was significantly improved by Pt/TiO₂, while the presence of Ag/TiO₂ enhanced the initial photocatalytic degradation rate of resorcinol slightly. Likewise, the photocatalytic mineralisation of resorcinol continued to be enhanced by Pt/TiO₂, but it was retarded when Ag/TiO₂ was used.

The function of Pt and Ag deposits on the surface of TiO₂ has been found to be markedly influenced by the interaction of resorcinol and its degradation products with the metal deposits. The presence of Pt or Ag on the surface of TiO₂ altered the distribution of degradation products of resorcinol as well as the production of photoactive species for the photocatalytic oxidation of resorcinol. The X-ray photoelectron spectroscopy (XPS), zeta potential and transmission electron microscopy (TEM) analyses have indicated that the contrasting effect of Pt and Ag deposits were governed by the oxidation states and the catalytic property of metal deposits. In addition to that, it has been found that the roles of metal deposits are specific and should not be generalised.     

Grain growth in TiO2-added ZnO–Bi2O3–CoO–MnO ceramics prepared by chemical processing

The effect of TiO₂ on the grain growth of the ZnO–Bi₂O₃–CoO–MnO ceramic system prepared by chemical coprecipitation, was studied between 1150 and 1300 °C in air. Bi₂O₃ melts during firing, and then TiO₂ dissolves into Bi₂O₃-rich liquid. TiO₂ initially reacts with Bi₂O₃ to form Bi₄Ti₃O₁₂. Above ≈1050 °C, Bi₄Ti₃O₁₂ reacts with ZnO to form Zn₂TiO₄ spinel phase. The kinetic study of grain growth carried out using the expression Gⁿ–G_oⁿ=K_o·t·exp(−Q/RT) gave grain exponent (n) value as 6 and the apparent activation energy (Q) as 226.46 kJ/mol. 1.00 mol% TiO₂ addition increased the grain growth exponent value from 6 to 7 and apparent activation energy with 1.00 mol% TiO₂ addition was found to be 197.10 kJ/mol. The ZnO grain size gradually increases with increasing TiO₂ content. Addition of TiO₂ may increase the reactivity of the Bi₂O₃-rich liquid towards the ZnO grain, thus affecting the ZnO grain growth.     

Mechanistic approach of the combined (iron–TiO2) photocatalytic system for the degradation of pollutants in aqueous solution: an attempt of rationalisation

Kinetics of oxidative photodegradation of Monuron (3-(4-chlorophenyl)-1,1-dimethylurea) in different photocatalytic systems (iron, TiO₂ and combined system iron + TiO₂) were investigated and compared. The influence of iron addition on TiO₂ photocatalyst and of TiO₂ on the photocatalytic cycle Fe(III)/Fe(II) were carefully studied. A very positive effect of iron addition was observed. This phenomenon was more and more pronounced when TiO₂ concentration was lower. In a suspension of TiO₂ (24 mg L⁻¹) with addition of Fe(III) (3 × 10⁻⁴ mol L⁻¹) the measured rate constant was similar to that obtained in a suspension of TiO₂ with a concentration more than 20 times higher (500 mg L⁻¹). The mechanistic approach carried out in this study allows us to identify the main reactions governing the combined system and a photochemical cycle was proposed. The optimisation of the photocatalytic systems was obtained when each photocatalyst plays a specific role: Fe(III) as a main OH radicals source and TiO₂ as an oxidizing agent of Fe(II).     

Photodegradation of aromatic pollutants in water over TiO2 supported on molecular sieves

TiO₂ was supported on porous materials, including NaY and Na-mordenite zeolites, as well as mesoporous MCM-41 molecular sieve by using impregnation method with organic solvents. The products were characterized with powder XRD, BET surface area measurement, TEM, IR, Raman and UV–VIS spectroscopies. The supported TiO₂ was crystallized in anatase structure and the intensity of its X-ray diffraction peaks increased with TiO₂ loading. In contrast, the total surface area of the supported catalyst decreased with TiO₂ loading. A blue shift of the absorption edge in the UV–VIS spectra was observed when TiO₂ particle size decreased, a phenomenon corresponding to the particle size quantization effect. For photodegradation of aromatic pollutants in water, the activity was found strongly influenced by the chemical nature of the pollutant and the surface property of the support. For volatile pollutants such as benzene and chlorobenzenes, molecular sieve supports facilitated the photodegradation reaction by providing high surface area for adsorption. Moreover, there is an optimal loading of TiO₂ to achieve the best photocatalytic activity on various supports. The supports in contrast did not show positive contribution in degradation of hydrophilic pollutants such as phenol.     

Pt/TiO_2催化二甲醚部分氧化重整制氢

二甲醚是一种理想的氢载体,可用于解决氢的储存和运输。以Pt/TiO_2为部分氧化催化剂,结合Ni/Al_2O_3重整催化剂,考察钛前驱体和焙烧温度对二甲醚部分氧化重整制氢反应的影响。结果表明,以Ti(C4H9O)4为原料制备的TiO_2为金红石相,Ti(SO4)2或Ti O(OH)2为原料制备的TiO_2为锐钛矿相;以Ti(C4H9O)4为原料制备的Pt/TiO_2-E催化剂催化性能略好,转化率接近100%,H2收率约90%,表明金红石相TiO_2负载的Pt催化剂略佳;以Ti(SO4)2为原料制备的Pt/TiO_2-S催化剂500℃焙烧可获得金红石相TiO_2。与Pt/Al_2O_3催化剂相比,Pt/TiO_2催化剂具有更好的催化性能,H2收率超过90%,而Pt/Al_2O_3催化剂H2收率约80%。     

TiO2、ZnO和TiO2/ZnO三种氧化物粉体材料的抗菌性能对比

氧化物具有化学性质稳定、原材料丰富易得的优点,其作为抗菌材料日益受到关注。对氧化物的抗菌性能及影响因素开展深入研究,能够为新型抗菌材料的开发提供科学依据。通过溶胶-凝胶法制备出了TiO₂/ZnO复合粉体,并将其与TiO₂、ZnO进行对比,分别对它们的晶相结构、微观形貌和粒径进行了表征。利用大肠杆菌ATCC25922作为受试菌株,通过抑菌环试验和菌液接触试验对3种氧化物粉体材料的抗菌性能进行测试。考察了钛锌比、光照等条件对抗菌效果的影响。结果表明,所使用的TiO₂主要由锐钛矿相和金红石相组成,ZnO主要为六方纤锌矿相,制备出的TiO₂/ZnO则主要是锐钛矿型TiO₂在六方纤锌矿型ZnO的孔隙间沉积而成,这3种粉体材料的粒径由大到小分别为TiO₂/ZnO、TiO₂和ZnO。从抑菌环和菌液接触试验的结果可以看出,ZnO粉体材料的抗菌效果明显优于TiO₂粉体材料,ZnO和TiO₂/ZnO在黑暗条件下仍有良好的抗菌性能,但在可见光照射条件下抗菌效果更佳。ZnO含量是TiO₂/ZnO复合材料抗菌性能的关键因素。制备TiO₂/ZnO粉体材料时的煅烧温度对其抗菌性能没有明显影响。