Immobilization of RuS2 Nanoparticles Prepared in Reverse Micellar System onto Thiol-Modified Polystyrene Particles and their Photocatalytic Properties

RuS₂ nanoparticles, smaller than 3 nm in diameter, were prepared by H₂S gas injection into the AOT/isooctane reverse micellar solution containing RuCl₃ aqueous solution. The nanoparticle size was found to be independent of the W_o (water content) value of the reverse micellar system, as shown by TEM observation. The recovery and immobilization of the RuS₂ nanoparticles from reverse micelles onto thiol-modified polystyrene particles (PSt-SH) were successfully carried out, by the addition of PSt-SH into the reverse micellar solution under conditions of mild stirring. The resulting composites, PSt-RuS₂, showed photocatalytic activity for H₂ generation form aqueous solution containing 2-propanol and Na₂SO₃ as sacrificial electron donors.     

H2O2络合凝胶法制备纳米TiO2/SiO2复合催化剂及其光催化性能

采用H2O2络合凝胶法获得钛的络合物[TiO(H2O2)]2 水溶胶,并与SiO2水溶胶包覆复合,制备了纳米TiO2/SiO2复合半导体催化剂,其结构经XRD和BET表征。以含阳离子艳红染料模拟废水降解为模型反应,考察了复合催化剂的光催化性能。实验结果表明:经650℃焙烧后的复合催化剂中TiO2粒径为9.8 nm,光催化活性最好,SiO2的最佳掺杂量为25%。     

磷钨酸/SiO_2负载化光催化剂的制备与表征

以溶胶–凝胶法合成的SiO2作载体,固载磷钨酸制得负载化磷钨酸光催化剂,用XRD、FT-IR、UV-Vis-DRS等方法表征了催化剂的理化性能。结果表明,所制备的负载化磷钨酸催化剂对甲基橙的光催化降解反应具有较好的催化性能。     

三维树枝状C/PbWO4催化剂的制备及其对不同染料的光催化降解性能

采用水热法合成了一种高结晶度的3D树枝状C/PbWO_4复合光催化剂(其中碳的质量分数分别为0.13%、0.26%、0.52%、0.78%)。应用X射线衍射、N2物理吸附、扫描电子显微镜、透射电子显微镜、能量色散X射线光谱、紫外可见漫反射光谱、光致发光光谱和光电流响应等手段对合成样品进行了表征。研究结果表明,当C的复合量为0.52%时,催化剂在降解偶氮染料酸性橙Ⅱ、甲基橙和罗丹明B呈现出最高的光催化活性,在光照100 min内对20 mg·L-1酸性橙Ⅱ的降解率达到97%,为纯Pb WO4的2.48倍。C/PbWO_4复合光催化剂活性提高的主要原因是掺杂在催化剂表面的C成为了电子俘获中心,有效俘获光生电子,促进光生电子和空穴分离的显著效果,从而产生更多活性物种(·OH、h+)参与染料分子的降解,提升光催化活性。     

Applications of Single-site Photocatalysts to the Design of Unique Surface Functional Materials

The isolated and tetrahedrally coordinated metal oxide (Ti, V, Cr, Mo and W-oxides) moieties can be included in the silica matrixes of silica-based microporous zeolite and mesoporous silica materials and named as “single-site photocatalysts”. Under UV-light irradiation these single-site photocatalysts form the charge transfer excited state, i.e., the excited electron–hole pair state which is located quite near to each other in different from the manner observed on semiconducting materials such as TiO₂, and play a significant role in various photocatalytic reactions. These single-site photocatalysts not only can promote photocatalytic reactions but also can be utilized to synthesis of functional materials. The nano-sized metal catalyst and visible-light sensitive binary oxide photocatalyst can be synthesized on the excited single-site photocatalyst under UV-light irradiation. The transparent mesoporous silica thin film with single-site photocatalyst generates the super-hydrophilic surface. In this review, our recent applications of single-site photocatalysts to synthesis of the surface functional materials have been introduced.     

B离子掺杂TiO2催化剂(TiO2－xBx)光催化活性的研究

采用溶胶-凝胶法制备出纳米TiO₂和TiO_2－xB_x催化剂. 光催化实验证明, TiO_2－xB_x催化剂的紫外、可见光催化活性均高于TiO₂. XRD, XPS和Raman结果表明, B离子是以取代式掺杂占据了TiO₂的O^2－的晶格位置. UV-Vis和PL谱的结果表明, B离子的2p轨道与O的2p轨道形成混合价带, 产生可见光响应, B离子的掺入有效地阻止了光生载流子的复合, 促进了其分离, 是TiO_2－xB_x催化剂紫外、可见光催化活性提高的主要原因.     

特定结构光催化剂的制备及其构效关系

高效光催化剂的设计是光催化研究的关键.本文介绍了超临界处理、醇解、溶剂蒸发诱导自组装(EISA)法和喷雾干燥技术在特定结构TiO2和非钛催化剂制备中的应用,并初步介绍了光催化剂的构效关系,说明具有特定组成和形貌结构的光催化剂的制备对提高光催化性能起到了关键的作用.     

Modulated Binary–Ternary Dual Semiconductor Heterostructures

A generic modular synthetic strategy for the fabrication of a series of binary‐ternary group II‐VI and group I‐III‐VI coupled semiconductor nano‐heterostructures is reported. Using Ag₂Se nanocrystals first as a catalyst and then as sacrificial seeds, four dual semiconductor heterostructures were designed with similar shapes: CdSe‐AgInSe₂, CdSe‐AgGaSe₂, ZnSe‐AgInSe₂, and ZnSe‐AgGaSe₂. Among these, dispersive type‐II heterostructures are further explored for photocatalytic hydrogen evolution from water and these are observed to be superior catalysts than the binary or ternary semi‐conductors. Details of the chemistry of this modular synthesis have been studied and the photophysical processes involved in catalysis are investigated.     

A High‐Energy Charge‐Separated State of 1.70 eV from a High‐Potential Donor–Acceptor Dyad: A Catalyst for Energy‐Demanding Photochemical Reactions

A high potential donor–acceptor dyad composed of zinc porphyrin bearing three meso‐pentafluorophenyl substituents covalently linked to C₆₀, as a novel dyad capable of generating charge‐separated states of high energy (potential) has been developed. The calculated energy of the charge‐separated state was found to be 1.70 eV, the highest reported for a covalently linked porphyrin–fullerene dyad. Intramolecular photoinduced electron transfer leading to charge‐separated states of appreciable lifetimes in polar and nonpolar solvents has been established from studies involving femto‐ to nanosecond transient absorption techniques. The high energy stored in the form of charge‐separated states along with its persistence of about 50–60 ns makes this dyad a potential electron‐transporting catalyst to carry out energy‐demanding photochemical reactions. This type of high‐energy harvesting dyad is expected to open new research in the areas of artificial photosynthesis especially producing energy (potential) demanding light‐to‐fuel products.     

The coating of conducting copolymer on coordination polymer nanorod: A visible light active p-n heterojunction photocatalyst for H2 production

A visible light active p-n heterojunction photocatalyst was synthesized successfully through in-situ chemical oxidation copolymerization of aniline (ANI) and diphenylamine-4-sulfonate (DPAS) with the existence of coordination polymer nanorod (CPNR) under initiation of ammonium persulfate (APS). Compared with neat coordination polymer nanorod, the resulted p-n heterojunction photocatalyst exhibits higher H₂ generationrate under visible light irradiation. In this heterojunction photocatalyst, as a p-type semiconductor possessing suitable energy levels with coordination polymer nanorod, poly-(aniline-co-N-(4-sulfophenyl)-aniline) (PAPSA) forms p-n heterojunction with n-type coordination polymer nanorod, the inner electric field of p-n heterojunction accelerates the separation of electrons and holes, which enhances H₂ production performance. Furthermore, the influence of concentration ratio between DPAS and ANI on photocatalytic property of the p-n heterojunction photocatalyst was discussed and a reasonable condition to fabricate photocatalyst with high H₂ generationrate had been obtained. During photocatalytic water splitting H₂ generation, the p-n heterojunction photocatalyst exhibited outstanding stability.