光源的选择对水溶性磺酸卟啉光催化对萘二酚类物质催化性能的影响

制备了水溶性磺酸卟啉(TPPS, TMPPS)及其铁配合物(FeTPPS). 以过氧化氢为氧源、 碘钨灯为光源, 水溶性磺酸卟啉可以高效光催化氧化1,5-萘二酚, 产物为5-羟基-1,4-萘二醌. 测定了卟啉的荧光量子产率及寿命, 分析了催化机理. 选择波长在350~650 nm区间内6个波段和功率在0~20 W区间内4种功率的光源, 探索了不同波段及功率的光源对卟啉光催化活性的影响. 研究结果表明, 不同波段的光源对卟啉光催化1,5-萘二酚的催化活性顺序为λ_380—385>λ_360—370>λ_580—585>λ_620—630>λ_492—577>λ_450—470, 该活性顺序与卟啉的紫外-可见吸收密切相关; 当使用相同波段光源时, 卟啉配体催化氧化1,5-萘二酚的反应速率常数与功率呈良好的线性关系; 卟啉铁配合物随着光源功率的增大, 其催化活性与光解程度有直接关系.     

系列水溶性磺酸卟啉的制备、表征及催化性能

改进磺化路线制备了5种取代基及取代位置不同的水溶性磺酸卟啉,利用氢核磁共振波谱(1H NMR)、傅里叶变换红外光谱(FTIR)、紫外-可见吸收光谱(UV-Vis)及质谱(MS)等手段对产物进行表征及性质研究.将该系列卟啉作为光催化剂,用于催化氧化1,5-萘二酚的反应,主催化产物为5-羟基-1,4-萘二醌,转化率为78%~95%.实验发现,磺酸基团在苯环上的位置以及取代基的数目、电子效应及立体位阻效应均会对催化结果产生影响,其中磺酸根的位置至关重要.动力学研究结果表明该催化氧化过程为一级反应.探讨了该反应的反应机理.     

水溶性卟啉催化氧化1,5-萘二酚

合成并表征了系列水溶性卟啉配体[H2TPPS: 5,10,15,20-四-(4-磺酸基苯基)-21H,23H-卟啉, H2TMPyP: 5,10,15,20-四(4-吡啶基)-21H,23H-卟啉, H2TCPP: 5,10,15,20-四-(4-羧基苯基)-21H,23H-卟啉]及相应的铁、锌及钴配合物. 将水溶性卟啉作为光敏剂, 用于1,5-萘二酚的光催化反应, 产物为5-羟基-1,4萘醌. 利用UV-Vis方法对卟啉催化1,5-萘二酚的反应过程进行了监测, 探索了水相和水/二氯甲烷双相催化体系, 确定了较为理想的反应条件. 探讨了不同取代基和不同金属离子对卟啉催化性能的影响, 初步讨论了催化机理. 结果表明, 具有磺酸根阴离子取代基的水溶性卟啉具有最好的催化活性; 卟啉的催化活性与其在反应体系中的稳定性密切相关; 铁卟啉在反应初期呈现很高的催化活性, 但在光照条件下容易发生光解而导致催化活性的降低; 无金属的磺酸卟啉在催化体系中的催化活性和稳定性最好.     

磺化2,3-萘酞菁锌(Ⅱ)、钴(Ⅱ)的电子吸收光谱和荧光光谱的研究

研究了磺化2，3-萘酞菁锌(Ⅱ)、钴(Ⅱ)在DMF(N，N-二甲基甲酰胺)、DMSO(二甲基亚砜)、乙醇、水等溶剂中的电子吸收光谱和荧光光谱．萘酞菁配合物的Q带与相应的酞菁配合物Q带相比，电子吸收光谱红移80～90nm，荧光光谱红移约100nm，荧光强度也显增加．在金属萘酞菁中引入磺酸基，配合物的电子吸收光谱Q带发生红移，但是影响不大、对于相同中心金属的配合物，改变溶剂的种类对配合物的电子吸收光谱的Q带影响较大．在金属萘酞菁环上引入一个磺酸基时，在相同溶剂中与无取代萘酞菁相比发生荧光光谱Q带红移，荧光强度增大．但在萘酞菁环上继续引入磺酸基时，荧光强度反而减少．磺化萘酞菁钴比磺化萘酞菁锌有较大的荧光强度．不同浓度下的电子吸收光谱和荧光光谱说明金属萘酞菁有集聚倾向、能形成基激缔合物．     

1-甲基-3,5-二苯基吡唑啉在氯化铜催化下的氧化脱氢反应(Ⅱ)——计量反应与氧分子的作用阶段

我们在合成1-甲基-3,5-二苯基吡唑(MDPP)的过程中,发现氯化铜、氯化钴等化合物对1-甲基-3,5-二苯基吡唑啉(H₂MDPP)的氧化脱氢反应具有优异的催化性能,对以氯化铜为催化剂的反应机理进行了初步研究,获得了反应过程中形成铜(Ⅱ)H₂MDPP、铜(Ⅱ)MDPP和铜(Ⅱ)H₂MDPP分子氧配合物的证据。另外,在催化氧化反应体系中曾检测到一价铜,这显然是氯化铜的还原产物,故本文对氯化铜与H₂MDPP的计量反应及在催化反应中氧分子参与作用的阶段进行了研究。     

两个半夹心型聚吡唑硼酸盐羧酸钴配合物的合成、结构及催化活性

设计合成了2个结构新颖的半夹心单核聚吡唑硼酸盐羧酸配合物Tp^*Co(Hglu)(CH₃OH)(1)和Tp^*Co(Hsub)(H₂O)(2)[Tp^*=三聚(3,5-二甲基吡唑)硼酸根, H₂glu=戊二酸, H₂sub=辛二酸], 并通过元素分析、 红外光谱、 紫外-可见光谱和X射线单晶结构分析对标题配合物进行了表征. 结构分析表明, 在配合物1和2中, 配体Tp^*都是三齿配位, 配位模式相同; 戊二酸和辛二酸都以μ₁-η¹-η¹的端基配位模式与金属相连. 此外, 还对配合物的热稳定性进行了详细分析, 并初步探讨了配合物催化氧化环己烷的催化活性.     

溴代酞菁铁配合物的光谱电化学性质研究

本文对μ-氧-四溴酞菁铁配合物([TBPcFe]₂O)的电化学性质及光谱电化学性质进行了研究。结果表明,μ-氧-四溴酞菁铁在所研究的电压区问内经历了三个单电子氧化还原反应,其半波电势为0.06V,—0.75V及—1.33V(相对于甘汞电极),分别对应于Fe³⁺/Fe³⁼、Fe²⁺/Fe⁺及TBPc^2-/TBPc^3-电对的氧化还原反应。光谱电化学性质研究亦观察到相应酞菁配合物的特征光谱。     

一系列萘羧酸膦酸镧系配合物的合成、结构和荧光性质

在溶剂热条件下,5-羧酸-1-萘膦酸(5-pncH₃)和稀土硝酸盐反应合成得到3例萘羧酸膦酸镧系配合物：[Pr(5-pnc)(H₂O)]·2H₂O (1)、[Sm(5-pnc)(H₂O)]·H₂O (2)和[Eu(5-pnc)(H₂O)]·H₂O (3)。采用单晶X射线衍射、粉末X射线衍射、元素分析、红外光谱、热重分析和荧光光谱对配合物进行了表征。晶体结构表明,每个七配位的镧系离子由来自5个膦酸盐配体的6个O原子和来自1个配位水分子的一个O原子配位。[LnO₇]通过O—C—O、O—P—O或—O—单元连接成一维双金属链结构,一维双金属链再进一步由萘羧酸膦酸配体(5-pnc^3-)连接成三维开放骨架结构。荧光性质研究表明,配合物3在330 nm的激发光下,发射Eu的红色特征荧光,而配合物1和2在蓝光区显示出非常宽的配体中心发射带。     

邻苯二酚衍生物与稀土元素配位反应的研究(Ⅴ)——3,4-二羟基苯甲酸与铈(Ⅲ)的配位与转型反应

研究了稀土元素铈(Ⅲ)离子与3,4-二羟基苯甲酸(H₃L)在水溶液体系中生成羧基配位化合物的条件,表征其组成为Ce(H₂L)₂(OH)·3H₂O,并研究了该配合物在一定条件下,铈离子由羧基配位反应变为由两个邻酚羟基配位的配合物[Ce(HL)_n]的转型反应及氧化成铈(Ⅳ)配合物的反应。     

1,5-双(1'-苯基-3'-甲基-5'-吡唑啉酮-4')-戊二酮-[1,5]和十六烷基吡啶盐的稀土配合物的合成及表征

合成了13种1,5-双(1′-苯基-3′-甲基-5′-吡唑啉酮-4′)-戊二酮-[1,5](BPMPPD)和溴化十六烷基吡啶盐(CPB)的稀土配合物.研究了配合物的红外光谱、紫外可见光谱、差热-热重谱、荧光光谱、核磁共振谱及摩尔电导等性质,发现配合物属离子型缔合物CP⁺[Ln(BPMPPD)₂]^-.Pr、Nd、Ho、Er、Tm配合物发生超灵敏跃迁.配合物的热分解温度具有"四分组"效应,Sm、Eu、Tb、Oy为线性荧光。     

Metal-free activation of H2O2 by g-C3N4 under visible light irradiation for the degradation of organic pollutants

Semiconducting carbon nitride materials were successfully prepared via a thermal poly-condensation of dicyandiamide as a precursor at >500 °C. The resulting materials were investigated as metal-free catalysts for the activation of H(2)O(2) with visible light under mild conditions, using the decomposition of Rhodamine B (RhB) in aqueous solution as a model reaction. Results revealed that carbon nitride catalysts can activate H(2)O(2) to generate reactive oxy-radicals under visible light irradiation without employment of any metal additives, leading to the mineralization of the dye. Factors affecting the degradation of organic compounds are pH values and the concentration of H(2)O(2). Recycling of the catalyst indicated no obvious deactivation during the entire catalytic reaction, indicating good (photo)chemical stability of metal-free polymeric carbon nitride photocatalysts for environmental purification. This study demonstrated a promising approach for the activation of green oxidant, hydrogen peroxide, by the newly-developed polymer photocatalysts for environmental remediation and oxidation catalysis.     

氮-硫共掺杂二氧化钛光催化剂的制备及其可见光催化活性

采用研磨煅烧法,以硫脲(TU)作为氮源和硫源,H2TiO3(HT)为TiO2的前驱体,制备了不同TU/HT比例的N,S共掺杂TiO2光催化剂(NS/TiO2);利用X射线衍射仪、透射电镜、X射线光电子能谱仪、拉曼光谱仪、紫外-可见吸收光谱仪等分析了NS/TiO2的晶体结构、显微形貌、典型元素的化学状态以及光谱性质;利用BET法测定了NS/TiO2的比表面积,同时测定了其在可见光照下催化降解罗丹明B的活性.结果表明,当TU/HT质量比为0.5时,NS/TiO2的光催化活性最佳,光照70min时的罗丹明B降解率为44.4%.氮元素以NH3形式吸附在TiO2表面,硫元素以S6+形式存在,部分S6+取代Ti 4+的位置.与此同时N,S共掺杂使得TiO2的禁带宽度减小,可见光催化活性提高.     

Y2O3/Ag3VO4复合可见光催化剂的制备及其光催化性能

以Na3VO4.12H2O,AgNO3和Y(NO3)3.6H2O为原料,采用浸渍法制备了Y2O3/Ag3VO4复合可见光催化剂,并用XRD,SEM,XPS,UV-Vis等测试手段表征了试样的结构和性能。结果显示,Y2 O3/Ag3VO4复合可见光催化剂为单斜结构,Y以Y2 O3的形式分散在Ag3VO4晶体的表面。UV-Vis测试结果表明,Y2O3/Ag3VO4较纯Ag3VO4吸收带边发生了红移,在可见光区的吸收增强;以金属卤灯(波长大于400 nm)为光源,研究了Y2O3/Ag3VO4催化剂对甲基橙(MO)的可见光催化降解性能。结果发现,Y2O3/Ag3VO4复合可见光催化剂的光催化活性较纯Ag3VO4均有大幅提高,其中Y掺杂量为4%时活性最高。     

Enhanced photodegradation of methylene blue with alkaline and transition‐metal ferrite nanophotocatalysts under direct sun light irradiation

It is highly desired to synthesize low‐cost photocatalysts for the degradation of colored dyes to safeguard our environment for the future generations. Here, we report an extremely efficient and low‐cost synthesis of alkaline earth and transition‐metal ferrite photocatalysts (MgFe₂O₄, CaFe₂O₄, BaFe₁₂O₁₉, CuFe₂O₄, and ZnFe₂O₄) from their chloride salts and their applications for the degradation of methylene blue (MB) dye under UV–visible and direct sunlight irradiation. The as‐prepared photocatalysts displayed enhanced photoactivities under both conditions of irradiation. After calcination at 600°C, the photocatalytic degradation increased significantly, and 96 and 85% MB was removed with ZnFe₂O₄ under UV–visible and direct sunlight irradiation, respectively. Moreover, large amounts of hydroxyl free radicals were produced under both irradiation conditions, which participated in the degradation of MB. The enhanced photodegradation activities of these photocatalysts are attributed to their extended visible light absorption and low bandgaps. This work will provide a feasible route to the synthesis of efficient and low‐cost photocatalysts to utilize sunlight for environmental remediation.     

Application of an Ion Beam Technique for the Design of Visible Light-Sensitive, Highly Efficient and Highly Selective Photocatalysts: Ion-Implantation and Ionized Cluster Beam Methods

As a new concept for the design of effective photocatalysts, an ion beam technology using accelerated metal ions, a metal ion implantation and an ionized cluster beam (ICB) method, have been applied to design unique photocatalysts. The metal ion implantation of TiO₂ and Ti-containing zeolites with highly accelerated metal ions (V⁺, Cr⁺, etc.) is useful in designing photocatalysts that can operate efficiently under visible light irradiation. Also, an ICB method with a low acceleration energy is useful in preparing transparent TiO₂ thin films on various types of substrates for the efficient photocatalytic degradation of pollutants diluted in water and air. The combination of the ICB method and metal ion implantation can develop the TiO₂ thin films that are able to operate not only under UV light but also under visible light irradiation.     

A comparative study of bismuth-based photocatalysts with titanium dioxide for perfluorooctanoic acid degradation

The fabricated bismuth-based photocatalysts presented an outstanding performance as compared to commercial TiO₂ (P25) for PFOA degradation under 254 nm UV light irradiation.     

高稳定性的氮掺杂氧化钽光催化甲醇C−H活化和直接C−C偶联制乙二醇

乙二醇是非常重要的基础化学品,不仅可以作为合成聚合物(如聚对苯二甲酸乙二醇酯)的重要单体,也可以用作防冻剂和燃料添加剂等,具有广泛的用途.乙二醇的年产量超过2500万吨,目前主要的工业合成路线是由石油衍生的乙烯通过环氧化制环氧乙烷,环氧乙烷再水解制乙二醇.甲醇是一种清洁的平台化合物,不仅可以由天然气和煤炭通过传统的合成气过程生产,也可以由生物质和CO2直接合成.直接以甲醇为原料是合成乙二醇的理想过程,但目前热催化还未实现该过程.通过太阳能驱动的C?H活化和C?C偶联过程,可以实现甲醇直接偶联制乙二醇的理想反应过程.光催化甲醇制乙二醇可以在十分温和的条件下进行,目前已报道的甲醇制乙二醇光催化剂均为硫化物半导体材料,如CdS,ZnS和Zn2In2S5,但硫化物存在的光腐蚀和毒性等问题迫使我们去发展一种更加稳定和环境友好的光催化剂.氧化物基半导体材料,如Ta2O5,TiO2,ZnO和WO3等,是一类相对硫化物半导体材料更加稳定的光催化材料,然而目前还没有氧化物基半导体光催化剂用于光催化甲醇制乙二醇的报道.本文率先将金属氧化物光催化剂Ta2O5,用于甲醇制乙二醇的光催化反应,实现了乙二醇的选择性合成.在单纯的Ta2O5催化剂上,乙二醇选择性可达73％.Ta2O5十分独特,可以实现甲醇的光催化C?C偶联制乙二醇,而其他金属氧化物光催化剂(如TiO2,ZnO,WO3和Nb2O5)光催化转化甲醇只生成甲醛和甲酸等C1产物.进一步通过简单、方便的氨气焙烧法,制备了一系列不同氮掺杂量的氧化钽(N-Ta2O5)催化剂.在未经助催化剂修饰的氮含量为2.3％的2％N-Ta2O5光催化剂上,乙二醇选择性为71％,生成速率可达4.0 mmol gcat?1 h?1,约为Ta2O5的9倍,同时显著高于已报道的未经助催化剂修饰的CdS催化剂性能.通过光电流、表面光电压谱和理论计算等方法系统地研究了氮掺杂氧化钽具有高的光催化甲醇制乙二醇性能的重要原因,发现氮掺杂氧化钽高的电荷分离能力是决定其具有高活性的关键因素.另一方面,氮掺杂氧化钽表现出了非常高的反应稳定性,在超过160 h的循环测试过程中,乙二醇的生成速率基本保持不变,这是目前已报道的金属硫化物光催化剂所未能实现的.在长达60 h的反应过程中,未经助催化剂修饰的2％N-Ta2O5催化剂上乙二醇生成量基本随时间线性增长,收率可达3.6％.进一步研究发现,钽基半导体材料(Ta2O5和N-Ta2O5)可以在保持甲醇羟基不变的情况下优先活化甲醇C?H键,生成羟甲基自由基(?CH2OH),随后羟甲基自由基经C?C偶联生成乙二醇.钽基半导体光催化剂是一种环境友好且十分稳定的甲醇光催化偶联制乙二醇的优异催化剂,未来基于该类催化剂不仅有希望发展出更加高效、稳定的甲醇制乙二醇光催化剂,还有希望为更广的羟基存在下的C?H键选择性活化反应过程设计高效稳定的催化剂提供借鉴和指导.     

Protein-based SERS technology monitoring the chemical reactivity on an α-synuclein-mediated two-dimensional array of gold nanoparticles

The enhancement of weak Raman signals has been challenged to obtain high-quality signals of surface-enhanced Raman scattering (SERS). By employing the Parkinson's disease-related protein of α-synuclein, we introduce SERS-active gold nanoparticles (AuNPs) individually isolated with an ultrathin α-synuclein shell and their 2-D array into a tightly packed monolayer on a glass support, which permits a quantitative SERS measurement of phthalocyanine tetrasulfonate (PcTS), a chemical ligand of the pathological protein. Subsequently, the PcTS-bound SERS substrate was also shown to be capable of discriminating two biologically important metal ions of iron and copper by detecting copper ion to the sub-ppm level in a highly selective manner via the in situ chemical reaction of metal chelation to PcTS. The strategy of using the protein-based 2-D AuNP SERS platform, therefore, could be further developed into a custom-made protein-based biosensor system for the detection of not only specific chemical/biological ligands of the immobilized coat proteins but also their biochemical reactivities.     

B掺杂TiO2/AC光催化剂的制备及活性

以硼酸和钛酸丁酯为主要原料，以活性炭(AC)为载体。用溶胶-凝胶法制备了B掺杂TiO2／AC光催化剂．用X射线衍射(XRD)、紫外可见漫反射吸收光谱(UV—VIS)对制得的光催化剂进行了表征．以甲基橙水溶液的光催化脱色反应和氧化乐果水溶液的光催化降解反应。考查了不同B掺杂TiO2／AC光催化剂的活性．结果表明，所有B掺杂TiO2／AC光催化剂均为锐钛矿晶相．B的掺杂未导致TiO2／AC光催化剂的吸收带边发生明显的移动．当B-TiO2质量分数分别为2．0％和2．5％时，TiO2／AC光催化剂的活性有明显的提高．B-TiO2质量分数2．0％时活性最高．但是，当B-TiO2质量分数分别为1．5％和3．0％时。TiO2／AC光催化剂的活性降低．B的缺电子特性可能改变了TiO2能带中的电子密度，使光催化反应中光生电子和空穴的俘获方式发生变化；同时。B的缺电子特性也会使光催化剂表面的Lewis酸强度增强，导致表面吸附OH-数量和目标反应物的吸附方式发生变化．这些可能是B-TiO2／AC光催化剂活性发生变化的主要原因．     

A comparative study of bismuth-based photocatalysts with titanium dioxide for perfluorooctanoic acid degradation

Bismuth-based material has been broadly studied due to their potential applications in various areas, especially used as promising photocatalysts for the removal of persistent organic pollutants (POPs) and several approaches have been adopted to tailor their features. Herein, the bismuth-based photocatalysts (BiOCl, BiPO₄, BiOPO₄/BiOCl) were synthesized by hydrothermal method and advanced characterization techniques (XRD, SEM, EDS elemental mapping, Raman and UV–vis DRS) were employed to analyze their morphology, crystal structure, and purity of the prepared photocatalysts. These synthesized photocatalysts offered a praiseworthy activity as compared to commercial TiO₂ (P25) for the degradation of model pollutant perfluorooctanoic acid (PFOA) under 254 nm UV light. It was interesting to observe that all synthesized photocatalysts show significant degradation of PFOA and their photocatalytic activity follows the order: bismuth-based catalysts > TiO₂ (P25) > without catalyst. Bismuth-based catalysts degraded the PFOA by almost 99.99% within 45 min while this degradation efficiency was 66.05% with TiO₂ under the same reaction condition. Our work shows that the bismuth-based photocatalysts are promising in PFOA treatment.