2D/1D复合材料C_3N_4/CdS的构筑及其光催化制氢性能研究

利用超声-沉积法将CdS纳米线复合到C3N4表面,制备出一系列2D/1D复合C3N4/CdS光催化剂。采用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外可见漫反射(UV-Vis-DRS)和荧光光谱(PL)等手段对复合材料的晶体结构、微观形貌和光学性能进行了表征和分析。采用可见光光催化分解水产氢的方法对其光催化性能进行评价,考察了复合催化剂的构筑方法以及CdS含量对复合光催化剂活性的影响,同时对影响其光催化性能的因素和机理进行了探讨。研究结果表明,CdS纳米线的引入在C3N4表面形成了无机/有机异质结构,显著提高了光催化产氢活性,且复合物中CdS与C3N4质量比为0.1时的产物光催化活性较佳。     

硫化镉/石墨烯复合光催化剂的微波水热合成及DFT研究

采用微波水热法制备了CdS/rGO纳米复合光催化剂,通过XRD、FTIR、XPS、SEM、TEM对其结构和形貌进行了表征,结合UV-Vis和密度泛函(DFT)计算对异质界面的电荷转移机制进行了研究。结果表明所得复合材料中CdS分散性好、显示出较高的可见光催化活性和光稳定性。当rGO含量为0.5 mg/mL时复合材料的光催化性能最佳,可见光照射120 min后亚甲基蓝(MB)的光降解率达到94.40%,且五次循环实验光催化效果接近。界面相互作用、差分电荷密度、平均静电势等计算结果表明CdS与rGO通过范德华弱相互作用形成稳定异质界面,电荷由CdS向rGO转移,电子和空穴在两相界面实现了有效分离,因而材料的光催化性能得到增强。     

镧、铁共掺杂TiO2/石英砂复合光催化材料的制备及性能研究?

采用超声强化溶胶-凝胶法,以无水乙醇和钛酸丁酯为前驱体,选取石英砂作为载体,制备了 La、Fe共掺杂TiO2/石英砂复合光催化材料.通过XRD、UV-Vis和SEM等测试手段对复合材料的微观结构和理化性质进行了表征分析,并选取 TNT 废液作为目标污染物,考察复合了光催化材料的光催化性能.结果表明,在紫外光照射下,适量的La、Fe共掺杂能够提高 TiO2/石英砂的光催化活性.当 La 掺杂量为1．0％(摩尔分数),Fe 掺杂量为0．25％(摩尔分数),焙烧温度为450℃时,复合材料的光催化性能最佳.     

核壳结构CdS/ZnS@rGA的制备及光催化性能研究

为研究纳米CdS/ZnS@rGA复合材料在可见光下的光催化性能,采用一步溶剂热法合成了以ZnS为壳的CdS/ZnS核壳纳米粒子,将CdS/ZnS核壳纳米粒子附着在rGO纳米片上,并组装成CdS/ZnS@rGA复合气凝胶,用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等对样品进行了表征,通过亚甲基蓝(MB)的光催化降解实验表明：CdS/ZnS@rGA复合气凝胶的形成不仅可以提高CdS的光稳定性,还可以增强对MB吸附能力,同时对MB的降解有明显的促进作用。可见光反应90 min, 50 mg的CdS/ZnS@rGA对100 mL 20 mg/L MB的去除率最高达到99%。经过5次循环实验,该材料仍具有较好的可重复利用性。     

La掺杂TiO_2/石英砂的制备及其光催化性能

采用超声强化溶胶-凝胶法,以硝酸镧和钛酸丁酯为前驱体,选取石英砂作为载体,制备了La掺杂TiO2/石英砂复合光催化材料,通过XRD、DSC-TG和SEM等测试手段对复合材料的结构和理化性质进行了表征分析,并选取TNT废液作为目标污染物,考察复合了光催化材料的光催化性能。结果表明,在紫外光照射下,适量的镧掺杂能够提高TiO2/石英砂的光催化活性,当镧掺杂量为1.5%(摩尔分数),焙烧温度为400℃时,复合材料的光催化性能最佳。     

原位复合制备纤维素基CdS纳米复合材料及其表征

以微晶纤维素(MCC)为模板,氯化镉、硫化钠等为原料,在水的悬浮液中,用原位复合法制备了MCC/CdS纳米复合材料。对复合反应条件进行了初步研究,探讨了Cd2+浓度、Cd2+吸附时间及超声功率对复合反应的影响。研究表明,适当提高Cd2+吸附时间及超声功率有利于提高复合材料中硫化镉颗粒的复合量,Cd2+浓度对复合量的影响是显著的。应用X射线衍射(XRD),扫描电镜(SEM),红外光谱(FT-IR),光致荧光光谱(PL)对MCC/CdS复合材料进行了表征。结果表明,复合在微晶纤维素上的CdS颗粒大小均一,且均匀分布在微晶纤维素模板表面;制备的复合材料具有一定的荧光特性。     

CdS-石墨相氮化碳复合光催化剂的制备及其光催化性能

以硫脲和四水合硝酸镉为前驱体,设计了低比例、高比例两种不同石墨相氮化碳（g-C₃N₄）与CdS质量比,以简单的软化学法制备了CdS-g-C₃N₄复合光催化剂,采用SEM、XRD、紫外-可见漫反射光谱（UV-Vis DRS）、FTIR、物理吸附等对CdS-g-C₃N₄复合光催化剂的结构和性能进行表征,并通过NO光催化降解实验探究了CdS-g-C₃N₄复合光催化剂在可见光下的光催化活性。结果表明:低CdS质量比的CdS-g-C₃N₄复合光催化材料中,当CdS与g-C₃N₄质量比为7%时,CdS-g-C₃N₄复合光催化剂的降解效果最好,降解率达31%;低g-C₃N₄质量比的CdS-g-C₃N₄复合光催材料中,当g-C₃N₄与CdS的质量比为5%时,CdS-g-C₃N₄复合光催化剂的降解效果最佳,降解率为36%。CdS与g-C₃N₄质量比为大比例的CdS-g-C₃N₄复合光催化剂中,当CdS与g-C₃N₄的质量比为4:1时,CdS-g-C₃N₄复合光催化剂的降解效率最高,达33%。且g-C₃N₄与CdS质量比为5%的CdS-g-C₃N₄复合光催化剂具有良好的光稳定性,降解效果最佳。      

CdS/T-ZnO_w复合材料的制备及光催化性能研究

采用化学水浴沉积法在T-ZnOw表面上沉积CdS纳米颗粒,用X射线衍射仪、扫描电镜和场发射表征样品的结构和形貌。并且在常温(25℃)下测试了CdS/T-ZnOw复合材料的光催化性能。结果表明,CdS/T-ZnOw复合材料的光催化性能直接受NH4Cl浓度的影响,可通过调控NH4Cl的浓度来调控CdS纳米颗粒的微观形貌。在0.74～2.99mmol/L范围内,CdS/T-ZnOw复合材料的光催化性能随NH4Cl浓度的增大而增大,在2.99～7.4mmol/L范围内,光催化性能随NH4Cl浓度的增大而减小。     

水热法制备纤维素基CdS纳米复合材料及其光催化性能研究

以棉花为纤维素基质,CdCl_2·21/2H_2O和L-半胱氨酸为原料,采用水热法制备了纤维素基CdS纳米复合材料。以亚甲基蓝(MB)为目标降解物,研究了反应时间和反应温度对该复合材料光催化性能的影响,通过XRD、SEM、FT-IR和UV-VisDRS对不同温度下制得的复合材料进行了结构表征。结果表明,反应温度为影响纤维素基CdS样品光催化活性的关键因素,且对样品中CdS的微观结构有显著影响。当反应温度为120℃时,样品的光催化活性最佳,反应50min对MB溶液的光降解率达到94.78%。经过3次循环其光降解率基本保持不变,表明纤维素基CdS是一种稳定有效的光催化剂。光催化增强机理分析表明,CdS光生电子迁移至纤维素表面,实现了与光生空穴的有效分离,从而增强了材料的光催化性能。     

一维CdS-Co_9S_8复合材料的制备及光催化产氢性能

通过溶剂热法将Co_9S_8纳米粒子负载在一维CdS纳米棒上,形成一维异质结复合材料用于光催化产氢。结合X射线衍射、扫描电子显微镜、紫外-可见漫反射等表征了材料的组成、微观结构、光学性能等,并进行光催化产氢性能测试。结果表明,当Co_9S_8的负载量为CdS质量的10%时复合材料具有最佳的产氢速率18.72 mmol·g~(-1)·h~(-1),约为CdS产氢速率的16倍。此外复合材料还表现出良好的循环稳定性,在连续12 h光催化产氢测试中,产氢性能没有明显下降。探讨了材料的电荷转移机制,从瞬态光电流、交流阻抗、光致发光等表征结果可知,一维异质结CdS-Co_9S_8可以显著提高光生电子-空穴对的迁移分离效率,从而显著提高材料光催化产氢性能。     

Growth of quantum-confined CdS nanoparticles inside Ti-MCM-41 as a visible light photocatalyst

CdS nanocrystallites have been successfully incorporated into the mesopores of Ti-MCM-41 by a two-step method involving ion-exchange and sulfidation. The X-ray diffraction patterns (XRD), UV-vis absorption spectra (UV-vis), photoluminescence spectra (PL), Raman spectra and N₂ adsorption-desorption isotherms were used to characterize the structure of the composite materials. It is found that most of the CdS nanocrystallites are about 2.6 nm, less than the pore diameter of Ti-MCM-41. The CdS nanocrystallites inside the mesopores of Ti-MCM-41 host show a significant blue shift in the UV-vis absorption spectrum. Under irradiation of visible light (λ > 430 nm), the composite material has greater and more stable photocatalytic activity for hydrogen evolution than bulk CdS, which can be explained by the effective charge separation between the CdS nanocrystallites and mesoporous Ti-MCM-41.     

Pt-Cu2O/TiO2复合催化剂的制备及光催化制氢活性

采用化学沉积法制备了Cu_2O/TiO_2复合光催化剂。通过扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射光谱(DRS)表征复合催化剂的微观形貌、元素组成、结构和光学特性。以H_2PtCl_6为无机前驱体对复合材料进行Pt负载,研究了不同Cu_2O含量对制氢活性的影响及不同光源下的制氢活性。结果表明,该复合催化剂表现出较好的光催化制氢活性,当Cu_2O的含量为1%(质量分数)时,氢气的产生量最高。     

Preparation, characterization and photocatalytic properties of CdS nanoparticles dotted on the surface of carbon nanotubes

Cadmium sulfide (CdS) nanoparticles dotted on the surface of multiwalled carbon nanotubes (MWCNTs) have been synthesized by the polyol method. The as-prepared materials were characterized by x-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, and Brunauer-Emmett-Teller adsorption analysis. The results indicate that CdS nanoparticles with diameter of 5-8?nm are thickly and uniformly coated on the surface of the MWCNTs. The photodegradation of azo dye using these materials was evaluated by the degradation of Brilliant Red X-3B under visible light. The coated nanotubes show higher photocatalytic activity than both CdS alone and a CdS/activated carbon sample; in addition, there is an optimum content of MWCNTs. The presence of MWCNTs can also hamper the photocorrosion of CdS. The mechanism for the enhancement of MWCNTs on the adsorption and photocatalytic property of CdS is investigated for the first time.     

Superior Photocatalytic H2 Production with Cocatalytic Co/Ni Species Anchored on Sulfide Semiconductor

Downsizing transition metal‐based cocatalysts on semiconductors to promote photocatalytic efficiency is important for research and industrial applications. This study presents a novel and facile strategy for anchoring well‐dispersed metal species on CdS surface through controlled decarboxylation of the ethylenediaminetetraacetate (EDTA) ligand in the metal–EDTA (M–EDTA) complex and CdS mixture precursor to function as a cocatalyst in the photocatalytic H₂ evolution. Microstructure characterization and performance evaluation reveal that under visible light the resulting pentacoordinated Co(II) and hexacoordinated Ni(II) on CdS exhibits a high activity of 3.1 mmol h^?1 (with turnover frequency (TOF) of 626 h^?1 and apparent quantum efficiency (AQE) of 56.2% at 420 nm) and 4.3 mmol h^?1 (with TOF of 864 h^?1 and AQE of 67.5% at 420 nm), respectively, toward cocatalytic hydrogen evolution, and the cocatalytic activity of such a hexacoordinated Ni(II) even exceeds that of platinum. Further mechanistic study and theoretical modeling indicate that the fully utilized Co(II)/Ni(II) active sites, efficient charge transfer, and favorable kinetics guarantee the efficient activities. This work introduces a promising precursor, i.e., M–EDTA for planting well‐dispersed transition metal species on the sulfide supports by a facile wet‐chemistry approach, providing new opportunities for photocatalytic H₂ production at the atomic/molecular scale.     

A composite photocatalyst of cdS nanoparticles deposited on TiO2 nanosheets

A nanocomposite photocatalyst consisting of deposited CdS nanoparticles on TiO2 nanosheets was fabricated by a simple one-pot method. The contact between two phases was maximized by making a composite structure of TiO2 nanosheet decorated with CdS nanoparticles. The composite photocatalyst showed higher photoactivity for hydrogen production from aqueous Na2S/Na2SO3 solution and decomposition of methylene blue under visible light irradiation (lamda > or =420 nm) compared with single component CdS nanoparticles or a physical mixture of CdS nanoparticles and TiO2 nanorods. The intentional formation of nanoscale heterojunctions between two phases appears beneficial for inducing an efficient electron-hole separation.     

壳聚糖-CdS复合纳米粒子对甲基橙的光催化降解作用

用反相微乳液法制备了壳聚糖-CdS复合纳米粒子,并考察了复合纳米粒子用量、光照条件和溶液pH值等因素对光催化降解甲基橙的影响.结果表明:在100 mL质量浓度为20 mg/L的甲基橙溶液中加入0.30 g复合纳米粒子,可以达到较好的光催化降解效果;甲基橙在光催化降解过程中最大吸收波长464 nm处的吸收峰迅速减弱,并最终消失,且在258 nm和455 nm处出现了新的吸收峰,说明甲基橙发生了降解;溶液pH值对光催化降解甲基橙有一定的影响,在弱酸性条件下降解效率较高;复合纳米粒子比普通CdS降解效率高,2 min时高出50%,400 min时高出21.3%.初步提出了复合纳米粒子光催化降解机理,复合纳米粒子的吸附作用是光催化降解作用的前置步骤.     

Cu2ZnSnS4-CdS复合材料的制备及其在光催化制氢中的应用

为了进一步提高Cu₂ZnSnS₄的光催化制氢性能,首先通过水热法制备出Cu₂ZnSnS₄光催化材料,在此基础上加入Cd（CH₃COO）₂·2H₂O和Na₂S进行二次水热反应制备Cu₂ZnSnS₄-CdS复合材料。通过XRD、SEM、TEM、Raman及XPS等分析测试方法对Cu₂ZnSnS₄-CdS复合材料的物相结构、微观形貌和元素价态进行了表征。结果表明:成功制备了结晶性能较好的Cu₂ZnSnS₄-CdS复合材料。Cu₂ZnSnS₄-CdS复合材料是由球状和块状颗粒组成;Cu₂ZnSnS₄-CdS复合材料表面>95%的Cd和S原子（原子比为1:1）的存在说明块状颗粒Cu₂ZnSnS₄表面生长的球形颗粒为CdS;在氙灯下的光催化制氢性能表明,Cu₂ZnSnS₄-CdS复合材料的光催化制氢效果明显优于Cu₂ZnSnS₄和CdS,产氢效率为296.17 μmol（g·h）-1。      

Nanoconfined Nickel@Carbon Core–Shell Cocatalyst Promoting Highly Efficient Visible‐Light Photocatalytic H2 Production

The realization of large‐scale solar hydrogen (H₂) production relies on the development of high‐performance and low‐cost photocatalysts driven by sunlight. Recently, cocatalysts have demonstrated immense potential in enhancing the activity and stability of photocatalysts. Hence, the rational design of highly active and inexpensive cocatalysts is of great significance. Here, a facile method is reported to synthesize Ni@C core–shell nanoparticles as a highly active cocatalyst. After merging Ni@C cocatalyst with CdS nanorod (NR), a tremendously enhanced visible‐light photocatalytic H₂‐production performance of 76.1 mmol g^?1 h^?1 is achieved, accompanied with an outstanding quantum efficiency of 31.2% at 420 nm. The state‐of‐art characterizations (e.g., synchrotron‐based X‐ray absorption near edge structure) and theoretical calculations strongly support the presence of pronounced nanoconfinement effect in Ni@C core–shell nanoparticles, which leads to controlled Ni core size, intimate interfacial contact and rapid charge transfer, optimized electronic structure, and protection against chemical corrosion. Hence, the combination of nanoconfined Ni@C with CdS nanorod leads to significantly improved photocatalytic activity and stability. This work not only for the first time demonstrates the great potential of using highly active and inexpensive Ni@C core–shell structure to replace expensive Pt in photocatalysis but also opens new avenues for synthesizing cocatalyst/photocatalyst hybridized systems with excellent performance by introducing nanoconfinement effect.     

Nano-CdS by polymer-inorganic solid-state reaction: Visible light pristine photocatalyst for hydrogen generation

We have explored the possibility of using environmentally stable nano-CdS embedded in thermally stable polymer matrix as an efficient photocatalyst for the hydrogen generation by photodecomposition of hydrogen sulphide under visible light irradiation. Initially, we restricted our attempt to the usage of nano-CdS synthesized by novel polymer-inorganic solid-state reaction between cadmium iodide and polyphenylene sulphide (PPS). The structural study revealed the formation of nanocrystallites of CdS with the particle size ranging from 6 to 28 nm entrapped in modified (cyclized) PPS matrix. A quantum yield of 19.7% for the H₂ generation was accomplished with CdS–PPS nanocomposite in pristine state, which appears to be superior in comparison to that of the conventional Pt loaded CdS. We believe that this straightforward approach can be extended to synthesise other nano-metal sulphides in polymer network for photocatalytic and allied applications.