Ternary Monolithic ZnS/CdS/rGO Photomembrane with Desirable Charge Separation/Transfer Routes for Effective Photocatalytic and Photoelectrochemical Hydrogen Generation

Highly efficient and easy recyclable monolithic photocatalysts with ideal separation/transport route for photogenerated charge carriers are much desired. In this work, a ZnO seed‐induced growth approach is developed to fabricate a ternary monolithic photomembrane, that is, ZnS/CdS heterojunction nanorods in situ grow into the interspaces of multilayer reduced graphene oxide (rGO) sheets (denoted as ZnS/CdS/rGO). The monolithic ZnS/CdS/rGO photomembrane can serve as an efficient visible‐light photoactive membrane for photocatalytic (PC) or photoelectrochemical (PEC) hydrogen generation. The fast electron transport of 1D CdS nanorods, the excellent electronic conductivity of multilayer stacked rGO sheets, the intense visible‐light absorption of CdS, the unique hierarchical structure, and double heterojunctions (ZnS/CdS and CdS/rGO) efficiently boost the photogenerated electron‐hole pairs separation and transfer across the interfacial domain of the photomembrane under visible‐light irradiation. Furthermore, the superior stability and reusability of the photomembrane is achieved by the ideal process of photogenerated electron‐hole pair separation/transfer, i.e., holes transfer to ZnS and electrons transfer to rGO to inhibit CdS from photocorrosion.     

钛基TiO2纳米管阵列电极的光电催化性能

应用电化学阳极氧化法在纯Ti基底上制备高度有序的TiO2纳米管阵列,考察了Ti/TiO2光阳极的光电化学响应.以苯酚溶液为目标污染物,研究Ti/TiO2电极的光电催化性能,并与光催化性能进行比较.结果表明,该电极光电催化性能优于光催化性能.施加0.6 V电压时,光电催化性能最好.电化学阻抗谱分析显示,光电催化和光催化降解过程的速控步骤均为表面反应步骤,外加偏压减小了界面电荷转移阻抗,提高了光生载流子的分离效率.     

In‐Situ Growth and Immobilization of CdS Nanoparticles onto Functionalized MoS2: Preparation,Characterization and Fabrication of Photoelectrochemical Cells

A facile strategy for the controllable growth of CdS nanoparticles at the periphery of MoS₂ en route the preparation of electron donor‐acceptor nanoensembles is developed. Precisely, the carboxylic group of α‐lipoic acid, as addend of the modified MoS₂ obtained upon 1,2‐dithiolane functionalization, was employed as anchor site for the in situ preparation and immobilization of the CdS nanoparticles in an one‐pot two‐step process. The newly prepared MoS₂/CdS hybrid material was characterized by complementary spectroscopic, thermal and microscopy imaging means. Absorption spectroscopy was employed to register the formation of MoS₂/CdS, by observing a broad shoulder centered at 420 nm due to CdS nanoparticles, while the excitonic bands of MoS₂ were also evident. Moreover, based on the efficient quenching of the characteristic fluorescence emission of CdS at 725 nm by the presence of MoS₂, strong electronic interactions at the excited state between the two species within the ensemble were identified. Photoelectrochemical assays of MoS₂/CdS thin‐film electrodes revealed a prompt, steady and reproducible anodic photoresponse during repeated on‐off cycles of illumination. A significant zero‐current photopotential of ?540 mV and an anodic photocurrent of 1 μA were observed, underlining improved charge‐separation and electron transport from CdS to MoS₂. The superior performance of the charge‐transfer processes in MoS₂/CdS is of direct interest for the fabrication of photoelectrochemical and optoelectronic devices.     

ZnIn2S4/Au纳米片阵列的制备及其可见光响应光电化学固氮特性

采用简单的水热法合成出单晶ZnIn₂S₄纳米片阵列以实现可见光响应光电化学固氮。并采用光沉积法将超细Au纳米颗粒（5 nm）沉积于ZnIn₂S₄纳米片的棱角位置处,实现了可见光俘获和载流子分离能力的同时增强。当负载合适含量的Au纳米颗粒,ZnIn₂S₄纳米片阵列的光电固氮活性由1.092 μg·cm^-2·h^-1提升至2.262 μg·cm^-2·h^-1。我们还提出一个简单模型用以阐明其性能增强机制,这也被光致发光（PL）谱和光电化学（PEC）性能结果所证实。     

BiVO4/ZnFe2O4同型异质结光阳极的构筑及其光电催化分解水性能

光生电子-空穴对的复合被认为是限制BiVO₄材料光电催化转换效率的重要原因之一。基于此,通过简单的水热-煅烧方法构筑了 BiVO₄/ZnFe₂O₄同型异质结光阳极,BiVO₄/ZnFe₂O₄复合光阳极在 1.23 V(vs RHE)下的光电流密度为 3.33 mA·cm^-2,较纯BiVO₄提升了2倍 (1.20 mA·cm^-2)。相关的结构及性能测试表明,BiVO₄和ZnFe₂O₄形成了带隙错开的n-n异质结,使得光生载流子得到有效分离,更有效地参与水氧化过程,进而提高了BiVO₄的光电催化水分解性能。     

CdS/TiO2纳米管复合结构的制备与光电性能研究

利用阳极氧化法在钛金属基体表面制备一层TiO₂纳米管阵列薄膜, 然后通过水热反应在TiO₂纳米管上负载CdS纳米粒子, 形成CdS/TiO₂纳米管的复合结构。利用SEM、XRD、XPS、UV-Vis等手段对其形貌和结构进行表征。进一步考察了CdS/TiO₂纳米管的光电性能和光催化活性, 结果表明, 相比于TiO₂纳米管, CdS/TiO₂纳米管复合结构在紫外光和可见光下都具有更好的光催化活性及光电性能。     

Photoelectrochemical Complexes of Fucoxanthin‐Chlorophyll Protein for Bio‐Photovoltaic Conversion with a High Open‐Circuit Photovoltage

Open‐circuit photovoltage (V_oc ) is among the critical parameters for achieving an efficient light‐to‐charge conversion in existing solar photovoltaic devices. Natural photosynthesis exploits light‐harvesting chlorophyll (Chl) protein complexes to transfer sunlight energy efficiently. We describe the exploitation of photosynthetic fucoxanthin‐chlorophyll protein (FCP) complexes for realizing photoelectrochemical cells with a high V_oc . An antenna‐dependent photocurrent response and a V_oc up to 0.72 V are observed and demonstrated in the bio‐photovoltaic devices fabricated with photosynthetic FCP complexes and TiO₂ nanostructures. Such high V_oc is determined by fucoxanthin in FCP complexes, and is rarely found in photoelectrochemical cells with other natural light‐harvesting antenna. We think that the FCP‐based bio‐photovoltaic conversion will provide an opportunity to fabricate environmental benign photoelectrochemical cells with high V_oc , and also help improve the understanding of the essential physics behind the light‐to‐charge conversion in photosynthetic complexes.     

热分解法制备Fe2O3修饰的TiO2纳米管阵列及其光电性能研究

为提高TiO_2纳米管阵列(TiO_2-NTs)的可见光活性,通过阳极氧化和热分解法制备了Fe_2O_3纳米粒子修饰的TiO_2纳米管阵列(Fe_2O_3/TiO_2-NTs)。通过扫描电子显微镜(SEM),透射电子显微镜(TEM)和紫外-可见光漫反射光谱(UV-vis DRS)等对产物进行了相关表征,同时测试了产物的光电性能及其光催化降解甲基橙的性能。结果显示,Fe_2O_3/TiO_2-NTs的光电流强度和光催化降解率分别是是TiO_2-NTs的19倍和8.7倍。     

二氧化钛空心微球的合成及其光电化学性能

采用水热法合成了TiO2空心微球,并通过XRD、SEM、TEM对其结构和形貌进行了分析.将TiO2空心微球作为光阳极制作成染料敏化太阳电池,并进行光电化学性能测试.结果表明,电流-电压曲线测试表明以TiO2空心微球为光阳极的电池光电转换效率远高于以TiO2纳米晶为光阳极的电池;紫外-可见吸收光谱及电化学阻抗谱(EIS)显示TiO2空心微球的光吸收能力增强,电池的电荷转移阻抗更低,表明其空心的球体结构是其光电性能提高的主要原因.     

Ti和乳酸共改性α-Fe2O3光阳极光电化学性能研究

采用一步水热后在氮气中进行热处理的方法制备了Ti和乳酸共改性的纳米花状α-Fe₂O₃光阳极。对样品分别进行了X射线衍射、扫描电镜、X射线光电子能谱、紫外-可见吸收光谱和光电化学性能测试。与乳酸改性的纳米片状α-Fe₂O₃光阳极相比,最优的Ti与乳酸共改性样品0.075LA-Fe2O3-0.75Ti光阳极的光电流密度从0.55mA·cm^-2提高到1.39mA·cm^-2。Ti改性明显减少了0.075LA-Fe₂O₃膜的表面态,增加了表面载流子注入效率;同时Ti的掺入也增加了电极体内载流子浓度,增强了体内载流子的传输效率。