A high H2 evolution rate under visible light of a CdS/TiO2@NiS catalyst due to a directional electron transfer between the phases

The photocatalytic activity of CdS can be greatly improved by co-modification of NiS and TiO_2 materials; furthermore the order of connection affects much. A directional electron transfer route via CdS → TiO_2→ NiS is found crucial to the enhancement of ternary catalyst, where TiO_2 acts as an electron reservoir and Ni S works as an effective cocatalyst. Cd S/TiO_2@Ni S with Ni S loaded on TiO_2 has an activity of H_2 evolution 2.5 times higher than NiS@Cd S/TiO_2 with Ni S pre-loaded on Cd S. Faster e-/h+separation rates is obtained of Cd S/TiO_2@Ni S under visible light than under extra UV light irradiation, which in turn demonstrates the importance of directional electron transfer route.     

Facile synthesis and enhanced visible-light photocatalytic activity of Ti3+-doped TiO2 sheets with tunable phase composition? ?

Ti³⁺-doped TiO₂ nanosheets with tunable phase composition (doped TiO₂ (A/R)) were synthesized via a hydrothermal method with high surface area anatase TiO₂ nanosheets TiO₂ (A) as a substrate, structure directing agent, and inhibitor; the activity was evaluated using a probe reaction-photocatalytic CO₂ conversion to methane under visible light irradiation with H₂ as an electron donor and hydrogen source. High-resolution transmission electron microscope (HRTEM), field emission scanning electron microscope, UV-Vis diffuse reflectance spectra, and X-ray diffraction (XRD) etc., were used to characterize the photocatalysts. XRD and HRTEM measurements confirmed the existence of anatase-rutile phase junction, while Ti³⁺ and single-electron-trapped oxygen vacancy in the doped TiO₂ (A/R) photocatalyst were revealed byelectron paramagnetic resonance (EPR) measurements. Effects of hydrothermal synthesis temperature and the amount of added anatase TiO₂ on the photocatalytic activity were elucidated. Significantly enhanced photocatalytic activity of doped TiO₂ (A/R) was observed; under the optimized synthesis conditions, CH₄ generation rate of doped TiO₂ (A/R) was 2.3 times that of Ti³⁺-doped rutile TiO₂.     

Au/TiO2复合物的制备、表征及其增强光催化灭菌活性

为提升TiO₂光催化活性克服其可见光响应能力差的问题,采用沉积-沉淀法制备了Au/TiO₂复合物光催化剂,利用X射线衍射（XRD）、傅里叶红外光谱（FTIR）、X射线光电子能谱（XPS）、紫外-可见漫反射光谱（UV-vis DRS）、荧光发射光谱等对样品进行了表征。XRD、FTIR和XPS结果表明,Au/TiO₂中TiO₂为锐钛矿相且Au成功沉积至TiO₂。UV-vis DRS和荧光发射光谱结果表明,适量Au修饰不仅能提高TiO₂对可见光的吸收,还可促进TiO₂光生电子-空穴对分离,有利于增强其光催化活性。自由基捕获实验证实,形成?OH的数量与光照时间成正比且?OH生成量越多,光催化活性越高。对比考察了Au/TiO₂和TiO₂在氙灯光源照射下对大肠杆菌的光催化杀灭作用,并探讨了Au负载量、光照时间、光照强度、光催化剂浓度等因素对灭菌性能的影响。结果表明：Au/TiO₂的光催化灭菌活性优于TiO₂,且与光照时间和光照强度均成正比;Au的适宜负载量为3%（质量分数）;3%Au/TiO₂在光照时间60min、光照强度7mW/cm²、光催化剂浓度100μg/mL的条件下,对大肠杆菌的杀灭效率高达91.3%。     

Efficient destruction of pathogenic bacteria with AgBr/TiO2 under visible light irradiation

The photocatalytic inactivation of pathogenic bacteria in water was investigated systematically with AgBr/TiO₂ under visible light (λ > 420 nm) irradiation. The catalyst was found to be highly effective for the killing of Escherichia coli, a Gram-negative bacterium, and Staphylococcus aureus, a Gram-positive bacterium. The decomposition of the cell wall and cell membrane was directly observed by TEM and further confirmed by K⁺ leakage from the inactivated bacteria. A possible cell damage mechanism by visible light-driven AgBr/TiO₂ is proposed. In addition, the effects of pH, inorganic ions on bacterial photocatalytic inactivation were investigated. The electrostatic force interaction of the bacteria–catalyst is crucial for the efficiency of disinfection. Moreover, AgBr/TiO₂ supported on porous nickel showed much higher bactericidal activity than fixed P25 TiO₂ under visible or near UV light irradiation.     

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。     

溶胶-凝胶-微波法制备银掺杂TiO_2光催化剂及其光催化性能

用硝酸银和钛酸正丁酯为原料,采用溶胶-凝胶-微波辐射干燥法合成银掺杂TiO_2光催化剂TiO_2-Ag。为了提高催化剂的光催化活性和降解有机污染物的速率,用微波辅助Ti O2-Ag光催化剂降解有机污染物。通过扫描电子显微镜、红外光谱法、紫外可见光谱法和荧光光谱法对TiO_2-Ag催化剂进行测试和表征。以甲基橙为有机污染物,分别在太阳光照射和微波、紫外、紫外-微波条件下降解甲基橙以考察催化剂的光催化活性。结果表明,TiO_2-Ag光催化剂最佳制备条件为:银掺杂量n(Ag+)∶n(Ti~(4+))=0.003,离子液体用量3.0 m L,微波干燥功率210 W,微波干燥时间20 min,焙烧温度650℃,焙烧时间3 h,此条件下制备的TiO_2-Ag光催化剂在太阳光照射4 h下,紫外光照、微波辐射和紫外光照-微波辐射分别辐射55 min后,甲基橙降解率分别为98.70%、98.79%和99.05%。     

色氨酸辅助合成光催化活性增强的球形纳米TiO2

以L-色氨酸（L-Trp）为生物模板,采用简单水解及煅烧后制备了球形结构TiO₂纳米光催化剂。通过X射线衍射、扫描电子显微镜、红外光谱、紫外-可见漫反射光谱、光致发光光谱和N₂吸附-解吸等方法对制得的TiO₂纳米材料进行表征。在催化剂合成过程中,L-Trp作为生物模板发挥至关重要的作用,能够指导球形结构纳米TiO₂的形成。考察了不同煅烧温度下制备的TiO₂样品光催化活性,结果表明550℃时制备的TiO₂样品具有优异的光催化活性,紫外光照射30min对甲基橙溶液的降解率达到95%左右,主要是由于较大比表面积和球形结构的协同效应。光催化剂稳定性实验表明,所制备的TiO₂纳米材料可作为一种实用有效的光催化剂用于紫外光照射下降解有机染料。同时,对L-Trp辅助下球形结构TiO₂纳米颗粒的可能生长机理进行讨论。     

B掺杂对负载型TiO_2光催化剂脱硝性能的影响

采用超声辅助溶胶-凝胶法制备活化半焦负载B掺杂TiO_2光催化剂,即B-TiO_2/ASC。在相同实验条件下,分别在紫外和可见光下研究其对模拟烟气的光催化氧化脱硝性能。结果表明,在紫外和可见光下,B掺杂光催化剂的活性得到提高,在可见光下的活性增加更加显著,反应180 min后仍可保持80%以上的脱硝率。结合XRD和FT-IR分析,可以看出B以取代掺杂的方式存在于TiO_2中并且导致TiO_2表面缺陷。表面缺陷有助于光生载流子的分离,从而延长光生电子的寿命并增加参与光催化反应的光生电子数量,从而产生更多的羟基自由基氧化NO,最终提高光催化脱硝率。     

Visible light photocatalysis on praseodymium(III)-nitrate-modified TiO2 prepared by an ultrasound method

Nanocrystalline TiO₂ incorporated with praseodymium(III) nitrate has been prepared by an ultrasound method in a sol–gel process. The prepared sample is characterized by X-ray diffraction (XRD), nitrogen adsorption (BET surface area), UV–vis diffuse reflectance spectroscopy (UV–Vis DRS) and X-ray photoelectron spectroscopy (XPS). The prepared material consists of TiO₂ nanocrystalline with 5 nm size incorporated with highly dispersed Pr(NO₃)₃. Visible light absorptions at 444, 469, 482 and 590 nm are observed in the prepared sample. These bands are attributed to the 4f transitions ³H₄ → ³P₂, ³H₄ → ³P₁, ³H₄ → ³P₀ and ³H₄ → ¹D₂ of praseodymium(III) ions, respectively. This sample Pr(NO₃)₃-TiO₂, as a novel visible light photocatalyst, shows high activity and stability in the decomposing rhodamine-B (RhB) and 4-chlorophenol (4-CP) under visible light irradiation. Results examined by electron spin resonance spectroscopy (ESR) reveal that the irradiation (>420 nm) of the photocatalyst dispersed in RhB aqueous solution induces the generation of highly active hydroxyl radicals (OH), leading to the cleavage of the whole conjugated chromophore structure of RhB. A mechanism based on local excitation of praseodymium(III) nitrate chromophore and interfacial charge transfer from the chromophore to TiO₂ is proposed to explain the formation of active hydroxyl radicals in the photocatalytic system under visible light irradiation.     

Photocatalytic degradation of organic compounds diluted in water using visible light-responsive metal ion-implanted TiO2 catalysts: Fe ion-implanted TiO2

The application of metal ion-implantation method has been made to improve the electronic properties of the TiO₂ photocatalyst to realize the utilization of visible light. The photocatalytic properties of these unique TiO₂ photocatalysts for the purification of water have been investigated. By the metal ion-implantation method, metal ions (Fe⁺, Mn⁺, V⁺, etc.) are accelerated enough to have the high kinetic energy (150 keV) and can be implanted into the bulk of TiO₂. TiO₂ photocatalysts which can absorb visible light and work as a photocatalyst efficiently under visible light irradiation were successfully prepared using this advanced technique. The UV-Vis absorption spectra of these metal ion-implanted TiO₂ photocatalysts were found to shift toward visible light regions depending on the amount and the kind of metal ions implanted. They were found to exhibit an effective photocatalytic reactivity for the liquid-phase degradation of 2-propanol diluted in water at 295 K under visible light (λ>450 nm) irradiation. The investigation using XAFS analysis suggested that the substitution of Ti ions in TiO₂ lattice with implanted metal ions is important to modify TiO₂ to be able to adsorb visible light.     

Fe-Sr2Bi2O5光催化降解低密度聚乙烯膜

采用共沉淀法合成的新型光催化剂(Fe-Sr₂Bi₂O₅)与低密度聚乙烯(LDPE)通过熔融共混制备了一种新型光催化降解复合膜(Fe-Sr₂Bi₂O₅/PE)。通过力学性能、接触角、傅里叶变换红外光谱(FT-IR)和场发射扫描电镜(FESEM)等表征手段研究了该催化剂在室温条件下固相光催化降解LDPE复合膜的性能变化。结果表明:Fe-Sr₂Bi₂O₅在紫外光和可见光条件下对LDPE均具有较好的光催化降解能力,其中,紫外灯照射10 d后,Fe-Sr₂Bi₂O₅/PE复合膜断裂伸长保留率低于5%,拉伸强度保留率低于40%,接触角降低22.52°,已完全脆化;同时,LDPE复合膜中出现明显的羰基等降解特征吸收峰和降解孔洞;与Sr₂Bi₂O₅和TiO₂相比,Fe-Sr₂Bi₂O₅对LDPE具有更好的降解效果。综上所述,在紫外光和可见光条件下,Fe-Sr₂Bi₂O₅对LDPE具有明显的光催化降解作用,为未来光催化降解聚乙烯(PE)提供了一定的新依据。     

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.     

CrO x /Ti-Al2O3催化剂结构及其催化丙烷脱氢性能

以模板法制备的Ti改性Al₂O₃为载体制备了CrO _x /nTi-Al₂O₃催化剂,考察了Ti含量对催化剂的结构及其催化丙烷脱氢性能的影响。采用X射线衍射（XRD）、N₂吸附-脱附、透射电子显微镜（TEM）、傅里叶变换红外光谱（FTIR）、拉曼光谱、X射线光电子能谱（XPS）、氨气程序升温脱附（NH₃-TPD）、吡啶红外吸附（Py-IR）等方法对催化剂的结构进行了表征。结果表明,CrO _x /nTi-Al₂O₃催化剂具有均匀的泡沫状介孔结构并含有少量微孔,表面积在180~195m²/g;铬主要以Cr⁶⁺和Cr³⁺形式存在,其中Cr⁶⁺主要以单铬酸盐和双铬酸盐形式存在,Cr³⁺以α-Cr₂O₃晶体和高分散Cr₂O₃形式存在,Ti的加入降低了催化剂表面Cr⁶⁺含量,增加了孔道内高分散Cr³⁺含量;Ti的加入降低了弱酸的强度,生成了少量中强酸,并使催化剂中B酸和L酸中心数量明显减少。少量的Ti（0.5%~1.0%TiO₂,质量分数）可明显提高丙烷转化率和丙烯收率,但过多的Ti（>2%TiO₂）则明显降低丙烯选择性而使丙烯收率降低。CrO _x /nTi-Al₂O₃催化剂表面Cr⁶⁺物种可催化丙烷氧化脱氢,本身还原成Cr³⁺后继续催化丙烷直接脱氢,孔道内部的高分散Cr³⁺可催化丙烷直接脱氢反应,二者结合使催化剂保持了较高的催化活性和较好的稳定性。     

纳米N掺杂TiO2的制备及可见光催化活性研究

N-doped TiO2 nanoparticle photocatalysts were prepared through a sol-gel procedure using NH4C1 as the nitrogen source and followed by calcination at certain temperature. Systematic studies for the preparation parameters and their impact on the structure and photocatalytic activity under ultraviolet （UV） and visible light irra-diation were carried out. Multiple techniques （XRD, TEM, DRIF, DSC, and XPS） were commanded to characterize the crystal structures and chemical binding of N-doped TiO2. Its photocatalytic activity was examined by the deg- radation of organic compounds. The catalytic activity of the prepared N-doped TiO2 nanoparticles under visible light （λ〉400nm） irradiation is evidenced by the decomposition of 4-chlorophenol, showing that nitrogen atoms in the N-doped TiO2 nanoparticle catalyst are responsible for the visible light catalytic activity. The N-doped TiO2 nanoparticle catalyst prepared with this modified route exhibits higher catalytic activity under UV irradiation in contrast to TiO2 without N-doping. It is suggested that the doped nitrogen here is located at the interstitial site of TiO2 lattice.     

Effects of hydrothermal temperature and time on the photocatalytic activity and microstructures of bimodal mesoporous TiO2 powders

Bimodal nanocrystalline mesoporous TiO₂ powders with high photocatalytic activity were prepared by a hydrothermal method using tetrabutylorthotitanate (TiO(C₄H₉)₄, TBOT) as precursor. The as-prepared TiO₂ powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and N₂ adsorption–desorption measurements. The photocatalytic activity of the as-prepared TiO₂ powders was evaluated by the photocatalytic degradation of acetone (CH₃COCH₃) under UV-light irradiation at room temperature in air. The effects of hydrothermal temperature and time on the microstructures and photocatalytic activity of the TiO₂ powders were investigated and discussed. It was found that hydrothermal treatment enhanced the phase transformation of the TiO₂ powders from amorphous to anatase and crystallization of anatase. All TiO₂ powders after hydrothermal treatment showed bimodal pore-size distributions in the mesoporous region: one was intra-aggregated pores with maximum pore diameters of ca. 4–8 nm and the other with inter-aggregated pores with maximum pore diameters of ca. 45–50 nm. With increasing hydrothermal temperature and time, the average crystallite size and average pore size increased, in contrast, the Brunauer-Emmett-Teller (BET) specific surface areas, pore volumes and porosity steadily decreased. An optimal hydrothermal condition (180 °C for 10 h) was determined. The photocatalytic activity of the prepared TiO₂ powders under optimal hydrothermal conditions was more than three times higher than that of Degussa P25.     

硅藻土负载La~(3+)/TiO_2光催化剂的制备及其光催化性能

以钛酸四丁酯为前驱体,硅藻土为载体,采用溶胶-凝胶法制备TiO_2/硅藻土负载型光催化剂。以硝酸镧为镧源,采用等体积浸渍-焙烧法制备La~(3+)/TiO_2硅藻土光催化剂。通过XRD和SEM对制备的催化剂进行表征,以亚甲基蓝溶液模拟有机废水,考察n(Ti)∶n(Si)及La3+掺杂量对催化剂光催化性能的影响,结果表明,硅藻土可提高TiO_2分散性,降低TiO_2晶粒尺寸,并抑制其由锐钛矿相向金红石相的转变。在n(Ti)∶n(Si)=1∶1、焙烧温度550℃和La3+掺杂质量分数1%条件下,La~(3+)/TiO_2硅藻土光催化剂的光催化活性较好,紫外光连续照射180 min,亚甲基蓝降解率可达99.9%。     

Photocatalytic oxidation of CO with various oxidants by Mo oxide species highly dispersed on SiO2 at 293 K

The photocatalytic oxidation of CO into CO₂ with oxidants such as NO, N₂O and O₂ proceeded efficiently on a Mo/SiO₂ with high Mo dispersion under UV light irradiation. It was found that the reaction rate greatly depended on the kind and concentration of the oxidant. Photoluminescence investigations reveal the close relationship between the reaction rate and the relative concentration of the photo-excited Mo⁶⁺-oxide species, i.e. charge transfer–excited–triplet state (Mo⁵⁺–O⁻)^*, under steady-state reaction conditions. Moreover, the photocatalytic oxidation of CO with O₂ in excess H₂ was carried out to test suitability for applications to supplying pure H₂. This reaction was seen to proceed efficiently on Mo/SiO₂ with a high CO conversion of 100% and CO selectivity of 99% after 180 min under UV light irradiation, showing higher photocatalytic performance than TiO₂ (P-25) photocatalyst. UV–vis, XAFS, photoluminescence and FT-IR investigations revealed that the high reactivity of the charge transfer–excited–triplet state (Mo⁵⁺–O⁻)^*, with CO as well as the high reactivity of the photoreduced Mo-oxide species (Mo⁴⁺-species) with O₂ to produce the original Mo-oxide species (Mo⁶⁺O²⁻), played a crucial role in the reactions.     

金属氧化物掺杂高岭土纳米 二氧化钛光催化复合材料研究

以高岭石为载体,以钛酸四丁酯为前驱体,采用溶胶-凝胶法制备金属氧化物掺杂高岭土纳米二氧化钛光催化复合材料。采用X射线衍射（XRD）、红外光谱（FT-IR）和拉曼光谱（Raman）对复合材料进行表征,并通过在紫外光下降解云母珠光工业废水来考察其光催化性能。研究了不同金属氧化物掺杂浓度对复合材料光催化活性的影响。实验结果表明：金属氧化物三氧化二铁、氧化锌掺杂使锐钛矿二氧化钛晶相特征衍射峰宽化,掺杂生成钛铁矿、红锌矿新相,影响锐钛矿二氧化钛结晶度。在紫外光下降解6 h,掺杂质量分数为0.5%的三氧化二铁对废水降解率为98.8%,掺杂质量分数为1.5%的氧化锌对其降解率为91.4%。     

Photocatalytic decomposition of 4-nitrophenol on Ti-containing MCM-41

A series of Ti-containing MCM-41 samples, such as Ti-MCM-41 with variable Si/Ti ratios and Cr–Ti-substituted TiO₂-loaded MCM-41 having different TiO₂ loading, were prepared and studied for the photocatalytic decomposition of 4-nitrophenol in UV and visible light. The samples were characterized using surface area measurement, XRD, FT-IR, and UV–vis DRS techniques. In the case of the Ti-MCM-41 samples with Si/Ti ratios higher than 20 which were found to have typical mesoporous structure, the framework incorporation of Ti into MCM-41 increased with decreasing Si/Ti ratio. On the contrary, the Ti-MCM-41 with lower Si/Ti ratio (Si/Ti = 10) shows low structural integrity and the formation of Ti-oxide species, leading to a considerable decrease in surface area. In the case of Cr–Ti-substituted TiO₂-loaded MCM-41 samples, significant absorption occurs in visible light and the absorption in both UV and visible region increases with increasing TiO₂ loading. However, when the amount of TiO₂ loaded on Cr–Ti-MCM-41 increased above 33 wt.%, the absorption in visible light increased slightly. Thus, it seems that, at higher TiO₂ loading, some TiO₂ particles are not closely bound to the wall of Cr–Ti-MCM-41. The photocatalytic activities of Ti-containing MCM-41 samples were strongly influenced by the amount of Ti. Under UV illumination, the highest photocatalytic activity for photocatalytic decomposition of 4-NP was observed for the Ti-MCM-41 having Si/Ti ratio of 20. Among various Ti-containing MCM-41 materials prepared in this work, only Cr–Ti-substituted TiO₂-loaded MCM-41 catalysts exhibited discernable photocatalytic activities in visible light, and their photocatalytic activities increased considerably with increasing TiO₂ loading up to 33 wt.%. Further increase in TiO₂ loading enhanced photocatalytic activity slightly.     

The preparation of coupled WO3/TiO2 photocatalyst by ball milling

The coupled photocatalyst WO₃/TiO₂ is prepared by ball milling by doping WO₃ into TiO₂ and using H₂O solution as disperser. The coupled photocatalyst WO₃/TiO₂ is characterized by UV–VIS diffuse reflection spectrum, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM). The results show that the optimum percentage of WO₃ doped is 3% and that the photocatalytic activity of the coupled WO₃/TiO₂ photocatalyst is much higher than that of TiO₂ and WO₃–TiO₂ with no ball milling. Compared with TiO₂, the photoexcited wavelength range of the WO₃/TiO₂ photocatalyst red-shifts about 50 nm, and the light absorption intensity is also improved. The crystal phase of TiO₂ is not changed and new crystal phases are not found during the process of ball milling. WO₃ and TiO₂ coupled highly, forming the WO₃/TiO₂ photocatalyst. The increased photocatalytic activity of the coupled photocatalyst may be attributed to the enhance charge separation efficiency and the extend wavelength range of photoexcitation.