Preparation of TiO_2/Ti mesh photoelectrode and properties

An innovative photoelectrode, TiO_2/Ti mesh electrode, was prepared by anodisation. In anodisation, 0.5 mol/L H_2SO_4 was used as electrolytic solution, the current had been constantly 1A from the beginning of the oxidation until reaching a designed voltage. Results showed that the photocatalytic activity of electrode was better when the designed voltage was 160 V. The morphology and the crystalline texture of the TiO_2 film on mesh electrode were examined by scanning electronic microscopy and Raman spectroscopy respectively. The examination results indicated that the structure and properties of the film depended on anodisation rate, and the anatase was the dominant component under the controlled experimental conditions. Degradation of Rhodamine B in photocatalytic (PC) and photoelectrocatalytic (PEC) reaction was investigated.

TiO2 Nanoparticles Produced by Electric-Discharge-Nanofluid-Process as Photoelectrode of DSSC

Self-made TiO2 nanoparticles were used as photoelectrode material of dye sensitized solar cell. The TiO2 thin film coats through spreading nanoparticles evenly onto the ITO glass via self-made spin-heat platform, and then TiO2 thin film is soaked in the dye N-719 more than 12 h to prepare the photoelectrode device. The TiO2 nanoparticles produced by electric-discharge-nanofluid-process have premium anatase crystal property, and its diameter can be controlled within a range of 20-50 nm. The surface energy zeta potential of nanofluid is from -22 mV to -28.8 mV, it is a stable particle suspension in the deionized water. A trace of surfactant Triton X-100 put upon the surface of ITO glass can produce a uniform and dense TiO2 thin film and heating up the spin platform to 200 oC is able to eliminate mixed surfac-tant. Self-made TiO2 film presents excellent dye absorption performance and even doesn＇t need heat treatment procedure to enhance essential property. Results of energy analysis show the thicker film structure will increase the short-circuit current density that causes higher conversion efficiency. But, as the film structure is large and thick, both the open-circuit voltage and fill factor will decline gradually to lead bad efficiency of dye-sensitized solar cell.

Nanocarbon-Enhanced 2D Photoelectrodes:A New Paradigm in Photoelectrochemical Water Splitting

Solar-driven photoelectrochemical(PEC)water splitting systems are highly promising for converting solar energy into clean and sustainable chemical energy.In such PEC systems,an integrated photoelectrode incorporates a light harvester for absorbing solar energy,an interlayer for transporting photogenerated charge carriers,and a co-catalyst for triggering redox reactions.Thus,understanding the correlations between the intrinsic structural properties and functions of the photoelectrodes is crucial.Here we critically examine various 2D layered photoanodes/photocathodes,including graphitic carbon nitrides,transition metal dichalcogenides,layered double hydroxides,layered bismuth oxyhalide nanosheets,and MXenes,combined with advanced nanocarbons(carbon dots,carbon nanotubes,graphene,and graphdiyne)as co-catalysts to assemble integrated photoelectrodes for oxygen evolution/hydrogen evolution reactions.The fundamental principles of PEC water splitting and physicochemical properties of photoelectrodes and the associated catalytic reactions are analyzed.Elaborate strategies for the assembly of 2D photoelectrodes with nanocarbons to enhance the PEC performances are introduced.The mechanisms of interplay of 2D photoelectrodes and nanocarbon co-catalysts are further discussed.The challenges and opportunities in the field are identified to guide future research for maximizing the conversion efficiency of PEC water splitting.

Physicochemical Characterization of Photoelectrodes of Ti/TiO₂Prepared by Thermal Oxidation of Titanium

The preparation and study of supported TiO2 for photocatalytic application in solar cell devices is a relevant research field. Thin films of TiO2 prepared on Ti by thermal oxidation in a wide range of temperatures (450°C - 900°C) were characterized by electrochemical impedance spectroscopy, potentiometry and amperometry. This material presents photoelectrochemical activity, which depends dramatically of the oxidation temperature and the exposition time at the studied temperatures. The flatband potential as well as the donor density and the resistance to the charge transfer were measured. All these parameters are temperature dependent, and the optimal values are observed on the photoelectrodes prepared at 750°C. This result is consistent with the photochemical response reported in the literature for thin films of Ti/TiO2 prepared under similar conditions.

Kinetics of photoelectrocatalytic degradation of endocrine disrupting chemicals using sulfur-doped TiO_2 /Ti photoelectrodes

In this study,sulfur-doped TiO2 /Ti photoelectrodes were prepared by anodization. The morphology, crystalline structure,composition of sulfur-doped TiO2 /Ti film and light absorption property were examined by SEM,XRD,XRF,XPS and UV/VIS respectively. Dimethyl phthalate( DMP) ,one kind of environmental disrupting chemicals( EDCs) ,was degraded by the optimized photoelectrodes. Power of xenon light,initial concentration of DMP,photoelectrocatalytic( PEC) area of photoelectrode and bias were investigated in the study on kinetics of PEC degradation of DMP. Hence,this study concluded that the optimum conditions were power of xenon light 150 W,initial concentration of DMP 1 mg/L,PEC area of sulfur-doped TiO2 /Ti photoelectrode 10 cm2,bias 1. 3 V in the PEC reaction system.

SiO_2掺杂对Ru-TiO_2催化剂的结构及其对丁二酸湿式氧化活性的影响

在TiO2粉末中掺杂SiO2,制备0—20%的SiO2TiO2载体.利用浸渍法在载体上负载Ru,制备Ru/SiO2TiO2催化剂.结果表明,催化剂的晶相以锐钛矿为主,晶粒尺寸为30—50nm.掺杂的SiO2主要为无定型,以5—15nm分散于催化剂中,比表面积随SiO2掺杂量的增加显著增大,但对TiO2的晶体结构无明显影响,也未形成Si—O—Ti键.Ru因粒径细化及含量过低未产生衍射峰.在300ml间歇式反应釜中,反应温度210—270℃,初始氧分压085MPa条件下,对丁二酸(74g·l-1,COD=7000mg·l-1)的催化湿式氧化结果表明,SiO2掺杂量对COD的去除率有显著影响,掺杂10%SiO2的催化剂对COD的去除率最高.在连续十次运行中,COD的去除率保持在85%左右,活性未见降低.

Ru-TiO_2光电极的研制与性能研究

采用阳极氧化法制备Ru-TiO2光电极,通过紫外-可见漫反射吸收(UV-Vis-DRS)、X-射线衍射(XRD)和交流阻抗(EIS)对光电极的性能进行表征,探讨了氧化电压、煅烧温度、钌掺杂量的影响。结果表明:Ru掺杂后TiO2结晶更完全,光吸收强度明显提高。在HF电解液中,阳极氧化制备Ru-TiO2光电极的最佳条件为:氧化电压为20V,热处理温度600℃,钌掺杂量1%。不同条件Ru-TiO2光电极对甲基橙溶液进行脱色效果依次为:光电催化>光催化>电催化。

Enhanced photocatalytic degradation of methyl orange by CdS quantum dots sensitized platelike WO_3 photoelectrodes

CdS quantum dots sensitized platelike WO_3 photoelectrodes were successfully synthesized by a facile hydrothermal method and a modified chemical bath deposition(CBD) technique.To further improve the stability of the photoelectrodes in alkaline environment,the platelike WO_3 films were treated with TiCl_4 to form a nano-TiO_2 buffer layer on the WO_3 plate surface before loading CdSQDs.The resulting electrodes were characterized by using XRD,SEM,HR-TEM and UV-vis spectrum.The photocatalytic activity of the resulting electrodes was investigated by degradation of methyl orange(MO) in aqueous solution.The photoelectrochemical(PEC) property of the resulting electrodes was also characterized by the linear sweep voltammetry.The results of both the degradation of MO and photocurrent tests indicated that the as-prepared CdSQDs sensitized WO_3 platelike photoelectrodes exhibit a significant improvement in photocatalytic degradation and PEC activity under visible light irradiation,compared with unsupported CdSQDs electrodes.Significantly,coating the WO_3 plates with nano-TiO_2 obviously facilitate the charge separation and retards the charge-pair recombination,and results in a highest activity for QDsCdS/TiO_2/WO_3 photoelectrodes.

多孔TiO_2纳米薄膜修饰的镍基光电极的制备和性能

Nanostructured TiO 2 porous film supported on nickel was prepared through sol-gel process,and was used as photoelectrode in solar energy photoelectrochemical cell.It was found that short circuit photocurrent and open circuit photovoltage of the photoelectrodes increased with the increment of sintering temperature and thickness of TiO 2 film.Through STM,the pore quantity and diameter of nanostructured TiO 2 film were found to increase with the increment of sintering temperature.It was found that the transparence of different thickness nanostructured TiO 2 films coated on quartz did not change much.

光源对TiO_2光催化剂性能的影响

采用阳极氧化法制备了 Ti O2 /Ti薄膜半导体光电极 ,并测试了该电极在 2 5 4 nm和365 nm两种光源照射下苯酚的转化过程。实验表明 :2 5 4 nm波长光源下苯酚的降解以均相光氧化反应为主 ;365 nm波长的光照下 ,以多相光催化反应为主 ,电极上加偏压能明显提高反应速率。在三电极体系中 ,用频响分析系统测试了光电极的交流阻抗图谱 ( EIS) ,分析

氧化物复合电极的构筑及光电性能研究

寻找并开发经济可行、稳定可靠且高效的光电极材料是光电化学(PEC)水分解领域亟待解决的关键挑战。在众多候选材料中,氧化钨(WO_(3))凭借其独特的物理化学性质脱颖而出,成为备受青睐的优选材料之一。为了进一步优化氧化钨(WO_(3))光电极的光电性能,本文选用了无毒、化学稳定性优异且资源丰富的α-Fe_(2)O_(3),通过简单的水热法将其与WO_(3)有效结合,成功构筑了全氧化物WO_(3)/α-Fe_(2)O_(3)复合电极,并对其组织结构、光学性能和光电化学性能进行了表征分析。实验结果表明,在1.23 V vs.RHE的偏压条件下,该复合电极的光电流密度达到了0.56 mA/cm^(2),是WO_(3)光电极的1.87倍。这可归因于多方面的协同效应:WO_(3)一维纳米棒结构为电子提供了高效的传输通道,确保了高导电性;α-Fe_(2)O_(3)的引入不仅提高了可见光利用效率,还与WO_(3)形成了异质结结构,有效抑制了电子-空穴对的复合,促进了载流子的高效分离与传输,从而实现了光电性能的提高。本文为构筑经济、稳定且高效的光电极材料提供了一些理论参考。

BiZn_(x)/Si光电阴极的制备及其CO_(2)还原性能研究

将CO_(2)转化为高附加值的化学品是实现碳循环,缓解能源危机和环境问题的有效途径之一。金属与半导体复合电极,利用光电耦合技术为CO_(2)转化提供了一种新思路。本研究通过电沉积的方法在碱刻蚀处理后的Si片上制备了双金属Bi、Zn共修饰的Si基光电阴极(BiZn_(x)/Si),用于CO_(2)的光电催化还原。研究表明,引入金属Bi和Zn能够改善光的吸收性能,降低电化学阻抗,提高电化学活性比表面积(ECSA)。其中,BiZn_(2)/Si最优的光电极电化学比表面积可达0.15 mF·cm^(-2)。除此之外,研究发现双金属共同作用有助于增强电极对中间体*OCHO的吸附作用,在-0.8 V(vs.RHE)电势下,最优的光电阴极BiZn_(2)/Si生成HCOOH的法拉第效率高达96.1%。更重要的是,光电阴极BiZn_(2)/Si的光电流强度在10 h内维持-13 mA·cm^(-2),表现出良好的性能稳定性。

Bi_(2)MoO_(6)/TiO_(2)纳米棒阵列异质结构的制备及光电化学性能研究

为提高TiO_(2)光电极的光电化学性能,采用水热/溶剂热两步法在TiO_(2)纳米棒阵列上合成BiMoO/TiO_(2)异质结构。通过XRD、SEM、TEM、HRTEM、XPS、UV-Vis、PL对样品的物相、形貌、微结构、元素价态和光学性能进行分析,结果表明成功制备了BiMoO/TiO_(2)纳米棒阵列异质结构,BiMoO修饰TiO_(2)拓宽了光谱响应范围。电化学工作站测试表明,BiMoO与TiO_(2)形成异质结构有利于光生载流子的有效分离,获得了增强的光电化学性能。BiMoO/TiO_(2)异质结构(样品BMT-3)具有最大的光电流密度为2.589 mA/cm^(2),约为TiO_(2)(0.143 mA/cm^(2))的18倍,具有最大的光转换效率0.287%和最小的电荷转移电阻。能带结构表明,TiO_(2)的导带和价带电位比BiMoO的导带和价带更正。TiO_(2)和BiMoO形成的type Ⅱ型能带结构与可见光的扩展吸收之间的协同作用是光电化学性能提升的内在机理。

Visible Light Photoelectrocatalytic Degradation of Rhodamine B Using Ti/TiO2-NiO Photoanode

The method of Ti/TiO2-NiO photoelectrode prepared by using sol-gel method continued by calcination process was introduced. The prepared TiO2-NiO film was observed with XRD and TEM. The anatase-rutile TiO2 was mainly on the prepared TiO2-NiO composite surface electrode. In addition to NiO, the composite also formed NiTiO3 that increased with increasing calcination temperature. Photoelectrocatalytic degradation of Rhodamine B (RB) using this electrode was investigated, and anodic potential and pH were optimized. RB degradation was investigated under different conditions, and it showed that photoelectrocatalytic degradation could achieve efficient and complete mineralization of organic pollutant. Through comparison of the photoelectrocatalytic oxidation using the Ti/TiO2-NiO electrode operated by single photoanode with the Ti/TiO2-NiO electrode operated by several photoanode, it was found that the photoelectrocatalytic efficiency of that by series photoanodes was higher. Additionally, photoelectrocatalytic system was performed at the several different photoelectrodes, which verified the higher photocatalytic activity compared with the single photoelectrode.

Effect of Tantalum Doping on TiO₂Nanotube Arrays for Water-Splitting

This work is intended to define a new possible methodology for TiO2 doping through the use of electrochemical deposition of tantalum directly on the titanium nanotubes obtained by a previous galvanostatic anodization treatment in an ethylene glycol solution. This method does not seem to cause any influence on the nanotube structure, showing final products with news and interesting features with respect to the unmodified sample. Together with a decrease in the band gap and flat band potential of the TiO2 nanotubes, the tantalum doped specimen reports an increase of the photo conversion efficiency under UV light.

Current trending and beyond for solar-driven water splitting reaction on WO_(3)photoanodes

This review shows the importance of WO_(3)photoanode as a potentially low-cost,efficient,stable,and photoactive material for light-driven water splitting.For such,this manuscript aims to review the most recent publications regarding the strategies to improve the phoelectroactivity of WO_(3)films for water oxidation.In addition,this review aims to graphically highlight and discuss the general trendings of the photocurrent density response and stability test of the recent outstanding studies in the literature for photoelectrochemical water splitting application.The strategies covered in this review will not only concern the WO_(3)morphology and crystal plane growth,but also the many arrangements possibilities to improve the WO_(3)efficiency for water photoelectrooxidation,such as defect engineering based on oxygen vacancies,doping,decorations,and homo and heterojunctions.All these strategies are compared by the photocurrent density results and by the stability of these photocatalysts.The best results in this sense were observed in cases where the use of heterojunction was applied together with a desired morphology and crystal plane of the WO_(3)photoanode.However,the modifications that caused a decrease in the photocurrent density reaching values that are even lower than the pure WO_(3)were also discussed.In this way,this review intends to improve the knowledge about the synthesis and design of WO_(3)photoanodes to further obtain an efficient photocatalyst to minimize the recombination losses or losses across the interfaces and improve the photoelectroactivity for water splitting in the large-scale application.

Preparation of hierarchical TiO_2 microspheres for enhancing photocurrent of dye sensitized solar cells

Hierarchically structured TiO2 microspheres were prepared at a low temperature by combining a sol-gel process with a solvothermal route and characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. Results indicate that the phase structure of the as-prepared TiO2 products undergoes a transformation, which changes from amorphous microspheres with a smooth surface in the sol-gel process to hierarchical anatase ones consisting of nanocrystallines after the solvothermal treatment. The hierarchical anatase TiO2 microsphere shows large surface areas and good light scattering effects as the photoelectrodes for dye sensitized solar cells (DSSCs). DSSCs based on TiO2 microspheres exhibit an improvement power conversion efficiency of 6.58% and a high short current density of 13.83 mA/cm2 as compared to the commercial P25 based DSSCs with a power conversion efficiency of 4.94% and a high short current density of 10.28 mA/cm2.

Synthesis of nano-TiO2 assisted by diethylene glycol for use in high efficiency dye-sensitized solar cells

The performance of dye-sensitized solar cells（DSSCs） consisting of anatase TiO_2 nanoparticles that were synthesized via a hydrothermal method was studied.The synthesized TiO_2 nanoparticles were characterized by X-ray diffraction（XRD）,nitrogen sorption analysis,scanning electron microscopy（SEM）,high resolution transmission electron microscopy（HRTEM）,and UV-vis spectroscopy.Then the J-Vcurve,electrochemical impedance spectroscopy（EIS）,and open-circuit voltage decay（OCVD） measurement were applied to evaluate the photovoltaic performance of DSSCs.Compared with the commercial TiO_2nanoparticles（P25）,the synthesized-TiO_2 nanoparticles showed better performance.By adding diethylene glycol（DEG） before the hydrothermal process,the synthesized TiO_2 nanoparticles（hereafter referred to as TiO_2-DEG particles） shows narrower size distribution,larger specific surface area,higher crystallinity,and less surface defects than TiO_2（DEG free） particles.The analysis of photovoltaic properties of DSSCs based on TiO_2-DEG particles showed that the recombination of electron-hole pairs was decreased and the trapping of carries in grain boundaries restrained.It was believed that the photoelectrode fabricated with the as-prepared TiO_2 nanoparticles improved the loading amount of dye sensitizers（N719）.and enhanced the photocurrent of the DSSCs.As a result,the TiO_2-DEG particle based cells achieved a photo-to-electricity conversion efficiency（η） of 7.90%,which is higher than 7.53%for the cell based on TiO2（DEG free） and 6.59%for the one fabricated with P25.

WO_(3)@Fe_(2)O_(3) Core-Shell Heterojunction Photoanodes for Efficient Photoelectrochemical Water Splitting

Photoelectrochemical(PEC) hydrogen production from water splitting is a green technology to convert solar energy into renewable hydrogen fuel. The construction of host/guest architecture in semiconductor photoanodes has been proven to be an effective strategy to improve solar-to-fuel conversion efficiency. In this study, WO_(3)@Fe_(2)O_(3) core-shell nanoarray heterojunction photoanodes are synthesized from the in-situ decomposition of WO_(3)@Prussian blue(WO_(3)@PB) and then used as host/guest photoanodes for photoelectrochemical water splitting, during which Fe_(2)O_(3) serves as guest material to absorb visible solar light and WO_(3) can act as host scaffolds to collect electrons at the contact. The prepared WO_(3)@Fe_(2)O_(3) shows the enhanced photocurrent density of 1.26 m A cm^(-2)(under visible light) at 1.23 V. vs RHE and a superior IPEC of 24.4% at 350 nm, which is higher than that of WO_(3)@PB and pure WO_(3)(0.43 m A/cm^(-2) and 16.3%, 0.18 m A/cm^(-2) and 11.5%) respectively, owing to the efficient light-harvesting from Fe_(2)O_(3) and the enhanced electron-hole pairs separation from the formation of type-Ⅱ heterojunctions, and the direct and ordered charge transport channels from the one-dimensional(1D) WO_(3) nanoarray nanostructures. Therefore, this work provides an alternative insight into the construction of sustainable and cost-effective photoanodes to enhance the efficiency of the solar-driven water splitting.