光催化沉积法制备Pd膜的改进及Pd膜性能表征

对光催化沉积法（PCD）制备Pd膜进行了改进，使含有TiO2与Pd^2＋的悬浮液膜层在多孔陶瓷膜表面形成液体薄膜，该薄膜在紫外光直接照射下发生光催化还原反应，烧结后得到含TiO2及Pd晶种的超薄膜层，用化学镀修饰得致密Pd膜．采用SEM、EDAX方法对所制的Pd膜表征结果表明，Pd膜厚度为5～6μm．在350～500℃和0.05～0．15MPa下进行气体渗透实验，当温度为450℃时，H2渗透系数为4.07×10^-6mol／（m^2·s·Pa），N2的渗透量检测不出，高温热循环测试表明该Pd膜致密且具有良好的热稳性．

浸渍-沉积法制备一维Au/TiO_2的光催化性能研究

以钛酸纳米管为载体、HAuCl4为金前驱体,通过浸渍-沉积法制备一维金修饰TiO2光催化剂(Au/TiO2)。通过X射线衍射和紫外-可见漫反射吸收光谱研究材料的结构和性质。以甲基橙溶液作为模拟废液,研究Au/TiO2材料在紫外光条件下的光催化活性。研究表明,由于金可以接受电子,从而促进光生电子和光生空穴的分离,使TiO2的光催化活性提高;Au/TiO2的光催化活性还与金的含量密切相关,金的最佳负载量为1%(质量分数)。

光催化膜反应器在污废水处理中的应用研究进展

传统光催化氧化技术在催化剂应用形式方面存在诸多不可克服的制约因素,将光催化氧化技术与膜分离技术进行耦合可从不同角度较好解决此类难题;目前的光催化膜反应器主要有悬浮型、负载型和内嵌型光催化膜反应器3种;在全面论述各类光催化膜反应器的工艺特性的基础之上,针对当前光催化耦合分离膜在合理选择膜类型和膜孔径方面存在理论不足的现状,首次提出耦合分离膜在膜类型和膜孔径选择过程中所要遵循的理论原则、依据和一套可操作性极强的选择程序。

二氧化钛光催化回收金属银离子

研究了硝酸银水溶液的二氧化钛光催化还原沉积反应。在空气和氩气气氛中,光催化还原银效率没有明显差别,甲醇存在也没有明显促进银的光催化还原。该反应在碱性条件下有较大的还原速率。在低银离子浓度时,光催化能完全还原银离子。

光诱导约束刻蚀体系中的TiO_2纳米管阵列光电极上Cu的沉积及抑制

光诱导约束刻蚀可作为一种无应力的化学平坦化方法用于Cu的抛光。我们发现在光诱导约束刻蚀工件Cu的过程中,工具表面的TiO_2纳米管上可能出现Cu沉积。通过扫描电子显微镜及其能谱,X射线光电子能谱等方法分析其沉积形貌和成分组成,探究在工具-工件之间的微纳尺度液层中Cu光催化还原沉积的机制,并在模拟液中研究Cu沉积对刻蚀体系的影响。探究引入搅拌、加入络合剂对TiO_2纳米管表面Cu的沉积的抑制,并考察抑制措施对于工件Cu刻蚀的影响。结果表明Cu沉积会增强TiO_2纳米管光电极的光催化性能,但随着沉积量的增加,增强机制会发生变化;在尝试抑制Cu沉积时也发现改善传质以抑制Cu沉积的同时也会带来工件Cu的刻蚀增强;采用添加络合剂结合改善传质的方法有望在抑制Cu沉积的同时提高平坦化效果。所以抑制方法和条件的选择需兼顾对工具-工件之间微纳液层中的多个化学和传质过程的影响。这些研究对于进一步优化光诱导约束刻蚀体系及其在化学平坦化中的应用有重要的指导意义。

CdS量子点敏化TiO_2电极用于太阳能电池研究

采用光催化沉积的方法在TiO_2薄膜上沉积CdS量子点,TEM研究表明CdS量子点大小均一,直径为20nm左右。对CdS量子点制备过程进行了分析,发现生长原理为"原子原位生长过程"(Cd+S=CdS)。紫外-可见光测试结果表明CdS/TiO_2相对于TiO_2薄膜可以极大增强可见光的吸收率;将CdS/TiO_2组装成太阳能电池,电极表现出良好的光电性能,可以在太阳能电池等方面有很好的利用前景。

Controllable photochemical synthesis of amorphous Ni(OH)2 as hydrogen production cocatalyst using inorganic phosphorous acid as sacrificial agent

Loading of cocatalysts can effectively inhibit the recombination of photogenerated carriers in photocatalysts and greatly improve the photocatalytic hydrogen production rate. Cocatalysts can be deposited at the outlet points of electrons using a photochemical method, which is beneficial for the following photocatalytic hydrogen production reaction. H2PO2^– has been used in the photochemical reduction of transition metals because of its special properties. However, the particles formed in the presence of H2PO2^– are very large and highly crystalline, which may inhibit the activity of photocatalysts. In this study, we designed a new method for synthesizing photocatalysts by photodeposition using some other phosphates, aiming to prepare controllable weakly crystalline and small-size cocatalysts to improve the hydrogen production activity. The cocatalyst prepared using H2PO3^– as an inorganic sacrificial agent has an amorphous structure and an average size of about 10 nm. The optimal photocatalytic hydrogen production rate of the obtained Ni(OH)2/g-C3N4(4.36 wt%) is 13707.86 μmol·g^-1·h^-1, which is even higher than the activity of Pt-4.36 wt%/g-C3N4(11210.93 μmol·g^-1·h^-1). Mechanistic studies show that loading of Ni(OH)2 can efficiently accelerate the separation and transfer efficiency of photogenerated charge carriers.

Preparation of a p-n heterojunction 2D BiOI nanosheet/1DBiPO_4 nanorod composite electrode for enhanced visible light photoelectrocatalysis

In this study, a 2D BiOI nanosheet/1D BiPO4 nanorod/fluorine-doped tin oxide (FTO) composite electrode with a p-n heterojunction structure was prepared by a two-step electrodeposition method. Field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-visible diffuse reflectance spectroscopy, and electrochemical testing were used to characterize its composition, crystal morphology, and optical properties. The Bi- OI/BiPO4/FTO composite electrode has higher photoelectrocatalytic (PEC) activity for the degradation of tetracycline than pure BiPO4 and BiOI. The PEC activity of the composite was 1.98 times and 2.46 times higher than those of the BiOI/FTO and BiPO4/FTO electrodes, respectively. The effects of the working voltage and BiOI deposition time on the degradation of tetracycline were investigated. The optimum BiOI deposition time was found to be 150 s and the optimum working voltage is 1.2 V. Trapping experiments showed that hydroxyl radicals (·OH) and superoxide radicals (·O2-) are the major reactive species in the PEC degradation process. The BiOI/BiPO4/FTO composite electrode has good stability, and the tetracycline removal efficiency remains substantially unchanged after four cycles in a static system. The reason for the PEC efficiency enhancement in the BiOI/BiPO4/FTO composite electrode is the increased visible light absorption range and the p-n heterojunction structure, which promotes the separation and migration of the photogenerated electrons and holes.

Photochemical synthesis and enhanced photocatalytic activity of MnO_x/BiPO_4 heterojunction

Monoclinic BiPO4with rod-like shape was prepared via a CTAB-assisted hydrothermal route.MnOx nanoparticles were loaded on the surfaces of BiPO4rods by a photo-deposition process to form MnOx/BiPO4heterojunctions.The as-prepared samples were characterized by XRD,SEM,TEM,XPS,FL,and UV-Vis diffuse reflectance measurements.The results showed that MnOx nanoparticles were strongly anchored to the surfaces of BiPO4rods when the mole ratio of Mn to Bi was controlled at a low level,forming MnOx/BiPO4heterojunctions with effective and sound interfaces.The MnOx/BiPO4heterojunctions exhibited higher photoactivity than pristine BiPO4for photodegradation of methyl blue under UV irradiation,which could be attributed to the efficient charge transfer at the heterojunction interfaces.The higher light absorption ability of MnOx/BiPO4in the range of300?420nm compared with pristine BiPO4was also responsible for the enhanced photocatalytic activities of MnOx/BiPO4heterojunctions.

High photocatalytic activities of zinc oxide nanotube arrays modified with tungsten trioxide nanoparticles

Well‐aligned zinc oxide(ZnO)nanotube arrays loaded with tungsten trioxide(WO3)nanoparticles were synthesized by a process involving chemical bath deposition in combination with pyrolysis.The prepared ZnO–WO3composites were characterized by X‐ray diffraction,energy dispersive spectrometer,field emission scanning electron microscopy,X‐ray photoelectron spectroscopy,photoluminescence spectroscopy,Fourier transform infrared spectroscopy and UV–vis diffuse reflectance spectroscopy.The photocatalytic activities of the ZnO–WO3composite photocatalysts with different WO3contents for the degradation of the herbicide chlorinated phenoxyacetic acid(MCPA‐Na)under simulated sunlight irradiation were systematically evaluated.It was found that the WO3content had a great effect on the photocatalytic activity of the ZnO–WO3composites.The composite with3%WO3showed the highest photocatalytic activity,with a degradation rate of chlorinated phenoxyacetic acid of98.5%after200min with20mg of photocatalyst.This photodegradation rate was about twice that of the pristine ZnO nanotube array.The recombination of photogenerated electrons and holes was increasingly suppressed with the addition of WO3to ZnO.The high relative content of defects on the surface of the ZnO–WO3composites was beneficial to their photocatalytic activity in the degradation of chlorinated phenoxyacetic acid.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.

Preparation of BiPO4/graphene photoelectrode and its photoelectrocatalyitic performance

In this work, a two-step electrodeposition method was employed to prepare BiPO4 nanorod/reduced graphene oxide/FTO composite electrodes(BiPO4/r GO/FTO). The BiPO4/r GO/FTO composite electrode showed the higher photoelectrocatalytic(PEC) activity for the removal of methyl orange than pure BiPO4, which was 2.8 times higher than that of BiPO4/FTO electrode. The effects of working voltage and BiPO4 deposition time on the degradation efficiency of methyl orange were investigated. The optimum BiPO4 deposition time was 45 min and the optimum working voltage was 1.2 V. The trapping experiments showed that hydroxyl radicals(·OH) and superoxide radicals(·O2-) were the major reactive species in PEC degradation process. The BiPO4/r GO/FTO composite electrode showed the high stability and its methyl orange removal efficiency remained unchanged after four testing cycles. The reasons for the enhanced PEC efficiency of the BiPO4/r GO/FTO composite electrode was ascribed to the broad visible-light absorption range, the rapid transmission of photogenerated charges, and the mixed BiPO4 phase by the introduction of r GO in the composite electrode films.

Sulfur-mediated photodeposition synthesis of NiS cocatalyst for boosting H2-evolution performance of g-C3N4 photocatalyst

Modification of nickel sulfide cocatalysts is considered to be a promising approach for efficient enhancement of the photocatalytic hydrogen production performance of g-C3N4.Providing more NiS cocatalyst to function as active sites of g-C3N4 is still highly desirable.To realize this goal,in this work,a facile sulfur-mediated photodeposition approach was developed.Specifically,photogenerated electrons excited by visible light reduce the S molecules absorbed on g-C3N4 surface to S^2‒,and subsequently NiS cocatalyst is formed in situ on the g-C3N4 surface by a combination of Ni2+and S2‒due to their small solubility product constant(Ksp=3.2×10^‒19).This approach has several advantages.The NiS cocatalyst is clearly in situ deposited on the photogenerated electron transfer sites of g-C3N4,and thus provides more active sites for H2 production.In addition,this method utilizes solar energy with mild reaction conditions at room temperature.Consequently,the synthesized NiS/g-C3N4 photocatalyst achieves excellent hydrogen generation performance with the performance of the optimal sample(244μmol h^‒1 g^‒1)close to that of 1 wt%Pt/g-C3N4(316μmol h^‒1 g^‒1,a well-known excellent photocatalyst).More importantly,the present sulfur-mediated photodeposition route is versatile and facile and can be used to deposit various metal sulfides such as CoSx,CuSx and AgSx on the g-C3N4 surface,and all the resulting metal sulfide-modified g-C3N4 photocatalysts exhibit improved H2-production performance.Our study offers a novel insight for the synthesis of high-efficiency photocatalysts.

Photodeposition of earth‐abundant cocatalysts in photocatalytic water splitting:Methods,functions,and mechanisms

Photocatalytic water splitting based on semiconductor photocatalysts is a promising approach for producing carbon‐neutral,sustainable,and clean H_(2) fuel.Cocatalyst loading,which is an appealing strategy,has been extensively employed to improve the photocatalytic efficiency semiconductors.In view of the high cost and rare preservation of noble metal cocatalysts that significantly hinder their utilization for large‐scale energy production,various cocatalysts comprising earth‐abundant ele‐ments have been developed as noble‐metal‐free candidates using different methods to boost pho‐tocatalytic water splitting.Among these preparation strategies,photodeposition has attracted tre‐mendous attention in the deposition of earth‐abundant cocatalysts owing to its simplicity and mod‐erate availability,improved interfacial charge separation and transfer,and abundant active sites on the surface.In this review,we first summarize the deposition principles,deposition advantages,categories of cocatalysts,roles of cocatalysts,influencing factors,modification strategies,and design considerations in the photodeposition of earth‐abundant cocatalysts.The photodeposited earth‐abundant cocatalysts for the photocatalytic H_(2) evolution half reaction,photocatalytic O_(2) evo‐lution half reaction,and overall photocatalytic water splitting are discussed.Finally,some perspec‐tives on the challenges and possible future directions for the photodeposition of earth‐abundant cocatalysts in photocatalytic water splitting are presented.

Triethanolamine-mediated photodeposition formation of amorphous Ni-P alloy for improved H2-evolution activity of g-C3N4

Developing efficient,stable,and low-cost novel electron-cocatalysts is crucial for photocatalytic hydrogen evolution reaction.Herein,amorphous Ni-P alloy particles were successfully modified onto g-C3N4 to construct the Ni-P/g-C3N4 photocatalyst through a simple and green triethanolamine(TEOA)-mediated photodeposition method.It was found that the TEOA could serve as an excellent complexing agent to coordinate with Ni2+to form[Ni(TEOA)]^2+complex,which can promote the rapid and effective deposition of amorphous Ni-P alloy on the g-C3N4 surface.Photocatalytic tests suggest that the hydrogen-evolution performance of gC3N4 can be greatly promoted through integrating amorphous Ni-P alloy.Especially,the Ni-P/g-C3N4(5 wt%)exhibits the superior H2-generation activity(118.2μmol h^-1g^-1),which is almost 35.8 times that of bare g-C3N4.Furthermore,the amorphous Ni-P alloy cocatalyst can also serve as the general hydrogen-production cocatalyst to greatly enhance the photocatalytic performance of traditional semiconductor materials such as Ti O2 and Cd S.Based on the present results,the mechanism of the amorphous Ni-P alloy as the high-efficiency electron transfer medium was proposed for the boosted H2-generation rate.The present facile route may broaden the horizons for the efficient development of highly active cocatalysts in photocatalytic field.

M@MIL-100（Fe） （M = Au, Pd, Pt） nanocomposites fabricated by a facile photodeposition process： Efficient visible-light photocatalysts for redox reactions in water

Proper design and preparation of high-performance and stable dual functional photocatalytic materials remains a significant objective of research. In this work, highly dispersed noble-metal nanoparticles （Au, Pd, Pt） were immobilized on MIL-100（Fe） （denoted M@MIL-100（Fe）） using a facile room-temperature photodeposition technique. The resulting M@MIL-100（Fe） （M = Au, Pd, and Pt） nanocomposites exhibited enhanced photoactivities toward photocatalytic degradation of methyl orange （MO） and reduction of heavy-metal Cr（VI） ions under visible-light irradiation （A ≥ 420 nm） compared with blank-MIL-100（Fe）. Combining these results with photoelectrochemical analyses revealed that noble-metal deposition can effectively improve the charge-separation efficiency of MIL-100（Fe） under visible-light irradiation. This phenomenon in turn leads to the enhancement of visible-light-driven photoactivity of M@MIL-100（Fe） toward photocatalytic redox reactions. In particular, the Pt@MIL-100（Fe） with an average Pt particle size of 2 nm exhibited remarkably enhanced photoactivities compared with those of M@MIL-100（Fe） （M = Au and Pd）, which can be attributed to the integrative effect of the enhanced light absorption intensity and more efficient separation of the photogenerated charge carrier. In addition, possible photocatalytic reaction mechanisms are also proposed.

Three-dimensional ordered macroporous g-C_(3)N_(4)-Cu_(2)O-TiO_(2) heterojunction for enhanced hydrogen production

In this study,a g-C_(3)N_(4)-Cu_(2)O-TiO_(2) photocatalyst with a novel three-dimensional ordered macroporous(3DOM)structure was successfully prepared using a sacrificial template strategy and a photodeposition method.The influence of the special porous structure with cross pore channels on the photocatalytic properties of the as-prepared sample was studied in detail.Compared with the original photocatalyst(TiO_(2) with 3 wt%Pt),g-C_(3)N_(4)-Cu_(2)O-TiO_(2) exhibited a higher specific surface area and more active sites,thus accelerating the separation efficiency of the photogenerated electron-hole pair.Consequently,the as-prepared photocatalyst showed good photocatalytic performance,reaching a maximum hydrogen production rate of 12,108μmol g^(-1) h^(-1) and approximately five times higher than that of the pristine comparison sample.The enhanced photoactivity of the g-C_(3)N_(4)-Cu_(2)O-TiO_(2) heterojunction can be ascribed to its double p-n heterojunction and robust porous structure,where the photodeposited Cu_(2)O plays a synergistic catalytic role in the photocatalytic process and the outer clad g-C_(3)N_(4) layer prevents Cu_(2)O oxidation.Additionally,the possible photocatalytic mechanism was briefly discussed based on the experimental results.This work identifies viable pathways for developing low-cost heterojunction photocatalysts with highly efficient photocatalytic activity toward improved solar energy conversion.

Unique Cd1-xZnxS@WO3-x and Cd1-xZnxS@WO3-x/CoOx/NiOx Z-scheme photocatalysts for efficient visible-light-induced H2 evolution

Artificial Z-scheme photocatalytic systems have received considerable attention in recent years because they can achieve wide light-absorption, high charge-separation efficiency, and strong redox ability simultaneously. Nevertheless, it is still challenging to exploit low-cost and stable Zscheme photocatalysts with highly-efficient H2 evolution from solar water-splitting so far. Herein, we report a novel all-solidstate Z-scheme photocatalyst Cd1-xZnxS@WO3-x consisting of Cd1-xZnxS nanorods coated with oxygen-deficient WO3-x amorphous layers. The Cd1-xZnxS@WO3-x exhibits an outstanding H2 evolution reaction(HER) activity as compared with Pt-loaded Cd1-xZnxS and most WO3- and Cd S-based photocatalysts, due to the generation of stronger reducing electrons through the appropriate Zn-doping in Cd1-xZnxS and the enhanced charge transfer by introducing oxygen vacancies(W^5+/OVs) into the ultrathin WO3-x amorphous coatings. The optimal HER rate of Cd1-xZnxS@WO3- xis determined to be 21.68 mmol h^-1 g^-1, which is further raised up to 28.25 mmol h^-1 g^-1(about 12 times more than that of Pt/Cd1-xZnxS) when Cd1-xZnxS@WO3-x is hybridized by Co Ox and Ni Oxdual cocatalysts(Cd1-xZnxS@WO3-x/CoOx/NiOx)through in-situ photo-deposition. Moreover, the corresponding apparent quantum yield(AQY) at 420 nm is significantly increased from 34.6% for Cd1-xZnxS@WO3-x to 60.8% for Cd1-xZnxS@WO3-x/CoOx/NiOx. In addition, both Cd1-xZnxS@WO3-x and Cd1-xZnxS@WO3-x/CoOx/NiOx demonstrate good stability towards HER. The results displayed in this work will inspire the rational design and synthesis of high-performance nanostructures for photocatalytic applications.

Synergistic effect of atomic layer deposition-assisted cocatalyst and crystal facet engineering in SnS2 nanosheet for solar water oxidation

The severe bulk recombination and sluggish oxygen evolution reaction(OER)dynamics of photoanodes severely restrict the application of photoelectrochemical(PEC)devices.To solve these two problems,crystallographic facet orientation and cocatalyst emergence with a high-quality photoanode/cocatalyst interface were realized through an air annealing-assisted strategy to treat atomic layer deposition(ALD)-modified SnSnanosheet arrays.Based on experimental observations and theoretical calculations,the reduced(001)crystal facet of SnSdecreases the recombination of photogenerated carriers in the bulk and improves the carrier separation of the photoanode.Moreover,the unexpectedly formed ZnTiOSfilm decreases the overpotential of the surface OER,reduces interface recombination,and extends the carrier lifetime.These synergistic effects lead to significantly enhanced PEC performance,with a high photocurrent density of 1.97 mA cm^(-2)at 1.23 V vs.reversible hydrogen electrode(RHE)and a low onset potential of 0.21 V vs.RHE,which are superior to reported mostly SnS-based photoanodes.