3D ZnIn2S4微球/1D TiO2纳米带异质结构的光催化降解和还原性能

首先采用溶剂热法和高温煅烧法制备1D TiO₂纳米带,其次利用溶剂热法将1D TiO₂纳米带均匀地穿插到片层结构组装而成的3D ZnIn₂S₄微球中,所形成的异质结构能有效抑制光生电子-空穴的复合。二元ZnIn₂S₄微球/TiO₂纳米带复合光催化剂在高浓度染料罗丹明B(RhB)的光降解和Cr(VI)的光还原实验中表现出优异的性能。在模拟太阳光照射下,ZnIn₂S₄/TiO₂纳米带光催化降解RhB和还原Cr(VI)的效率相较于纯TiO₂颗粒(10%,22%)、TiO₂纳米带(45%,40%)、ZnIn₂S₄(62%,65%)、ZnIn₂S₄/TiO₂颗粒(90%,91%)分别提高至100%和100%。最后,通过紫外-可见...     

1D/2D TiO2/ZnIn2S4S型异质结光催化剂及其高效制氢性能

通过半导体催化剂利用太阳能分解水制氢被认为是解决人类面临的环境问题和能源危机的有效途径.在众多的半导体光催化剂中,TiO₂由于其良好的光化学稳定性、无毒性、丰富的形貌以及低廉的价格,在光催化制氢领域备受关注.然而TiO₂的内在缺陷,如较宽的带隙、较窄的光响应范围,光生电子空穴对的快速复合,极大限制了其太阳能制氢效率.构建异质结结构被认为是解决以上问题的一个有效方法,通过将TiO₂与另一个半导体复合可以提升催化剂对太阳光的吸收范围,也可降低光生电子空穴对的复合速率.但构建一个成功的异质结结构不仅要满足上述的要求,还需要保留异质结催化剂体系中光生电子和空穴的氧化还原能力.研究表明,S型异质结是将两个具有合适能带结构的半导体进行耦合,由于费米能级的差异,两个半导体间将发生电子转移,从而引起能带弯曲并形成内建电场.光照条件下,具有较弱还原能力的光生电子在内建电场和能带弯曲的作用下与较弱氧化能力的光生空穴复合,实现异质结催化剂体系中各个半导体内部光生载流子有效分离的目标,同时保留了异质结催化剂体系中较强氧化能力和较强还原能力的光生电子和空穴,进而实现光催化活性的提高.本文采用水热合成方法,将具有更强还原能力和可见光响应特性的半导体(ZnIn₂S₄)原位生长在TiO₂纳米纤维表面,构建了1D/2DTiO₂/ZnIn₂S₄S型异质结光催化剂.最优比例的TiO₂/ZnIn₂S₄复合材料表现出优越的光催化制氢活性(6.03mmol/h/g),分别是纯TiO₂和纯ZnIn₂S₄制氢活性的3.7倍和2倍.TiO₂/ZnIn₂S₄复合材料光催化活性的提高可以归因于紧密的异质结界面、光生载流子的有效分离、丰富的反应活性位点以及增强的光吸收能力.通过原位XPS和DFT计算研究了异质结内部光生电子的转移机制.结果表明,在光照条件下电子由TiO₂向ZnIn₂S₄迁移,遵循了S型异质结内部电子的转移机制,实现了TiO₂和ZnIn₂S₄内部光生载流子的有效分离,同时保留了具有较强还原能力的ZnIn₂S₄价带电子和较强氧化能力的TiO₂导带空穴,从而显著提升光催化制氢效率.综上,本文制备的TiO₂/ZnIn₂S₄S型异质结光催化剂很好地克服了TiO₂在光催化制氢领域所面临的诸多障碍,为设计和制备高效异质结光催化剂提供了新的思路.     

微波辅助快速制备2D/1D ZnIn2S4/TiO2 S型异质结及其光催化制氢性能

The threat and global concern of energy crises have significantly increased over the last two decades. Because solar light and water are abundant on earth, photocatalytic hydrogen evolution through water splitting has been considered as a promising route to produce green energy. Therefore, semiconductor photocatalysts play a key role in transforming sunlight and water to hydrogen energy. To date, various photocatalysts have been studied. Among them, TiO₂ has been extensively investigated because of its non-toxicity, high chemical stability, controllable morphology, and high photocatalytic activity. In particular, 1D TiO₂ nanofibers (NFs) have attracted increasing attention as effective photocatalysts because of their unique 1D electron transfer pathway, high adsorption capacity, and high photoinduced electron–hole pair transfer capability. However, TiO₂ NFs are considered as an inefficient photocatalyst for the hydrogen evolution reaction (HER) because of their disadvantages such as a large band gap (~3.2 eV) and fast recombination of photoinduced electron–hole pairs. Therefore, the development of a high-performance TiO₂ NF photocatalyst is required for efficient solar light conversion. In recent years, several strategies have been explored to improve the photocatalytic activity of TiO₂ NFs, including coupling with narrow-bandgap semiconductors (such as ZnIn₂S₄). Recently, microwave (MW)-assisted synthesis has been considered as an important strategy for the preparation of photocatalyst semiconductors because of its low cost, environment-friendliness, simplicity, and high reaction rate. Herein, to overcome the above-mentioned limiting properties of TiO₂ NFs, we report a 2D/1D ZnIn₂S₄/TiO₂ S-scheme heterojunction synthesized through a microwave (MW)-assisted process. Herein, the 2D/1D ZnIn₂S₄/TiO₂ S-scheme heterojunction was constructed rapidly by using in situ 2D ZnIn₂S₄nanosheets decorated on 1D TiO₂ NFs. The loading of ZnIn₂S₄ nanoplates on the TiO₂ NFs could be easily controlled by adjusting the molar ratios of ZnIn₂S₄ precursors to TiO₂ NFs. The photocatalytic activity of the as-prepared samples for water splitting under simulated solar light irradiation was assessed. The experimental results showed that the photocatalytic performance of the ZnIn₂S₄/TiO₂ composites was significantly improved, and the obtained ZnIn₂S₄/TiO₂ composites showed increased optical absorption. Under optimal conditions, the highest HER rate of the ZT-0.5 (molar ratio of ZnIn₂S₄/TiO₂= 0.5) sample was 8774 μmol·g^-1·h^-1, which is considerably higher than those of pure TiO₂ NFs (3312 μmol·g^-1·h^-1) and ZnIn₂S₄nanoplates (3114 μmol·g^-1·h^-1) by factors of 2.7 and 2.8, respectively. Based on the experimental data and Mott-Schottky analysis, a possible mechanism for the formation of the S-scheme heterojunction between ZnIn₂S₄ and TiO₂ was proposed to interpret the enhanced HER activity of the ZnIn₂S₄/TiO₂heterojunctionphotocatalysts.      

高催化活性2D/2D Ti3C2/Bi4O5Br2纳米片异质结的构建及其可见光催化去除NO

This study concentrated on the production of a two-dimensional and two-dimensional (2D/2D) Ti₃C₂/Bi₄O₅Br₂ heterojunction with a large interface that applied as one of the novel visible-light-induced photocatalyst via the hydrothermal method. The obtained photocatalysts enhanced the photocatalytic efficiency of the NO removal. The crystal structure and chemical state of the composites were characterized using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that Ti₃C₂, Bi₄O₅Br₂, and Ti₃C₂/Bi₄O₅Br₂ were successfully synthesized. The experimental results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the prepared samples had a 2D/2D nanosheet structure and large contact area. This structure facilitated the transfer of electrons and holes. The solar light absorptions of the samples were evaluated using the UV-Vis diffuse reflectance spectra (UV-Vis DRS). It was found that the absorption band of Ti₃C₂/Bi₄O₅Br₂ was wider than that of Bi₄O₅Br₂. This represents the electrons in the Ti₃C₂/Bi₄O₅Br₂ nanosheet composites were more likely to be excited. The photocatalytic experiments showed that the 2D/2D Ti₃C₂/Bi₄O₅Br₂ composite with high photocatalytic activity and stability. The photocatalytic efficiency of pure Bi₄O₅Br₂ for the NO removal was 30.5%, while for the 15%Ti₃C₂/Bi₄O₅Br₂ it was 57.6%. Moreover, the catalytic reaction happened in a short period. The concentration of NO decreased exponentially in the first 5 min, which approximately reached the final value. Furthermore, the stability of 15%Ti₃C₂/Bi₄O₅Br₂ was favorable: the catalytic rate was approximately 50.0% after five cycles of cyclic catalysis. Finally, the scavenger experiments, electron spin resonance spectroscopy (ESR), transient photocurrent response, and surface photovoltage spectrum (SPS) were applied to analyze the photocatalytic mechanism of the composite. The results indicated that the 2D/2D heterojunction Ti₃C₂/Bi₄O₅Br₂ improved the separation rate of the electrons and holes, thus enhancing the photocatalytic efficiency. In the photocatalytic reactions, the photogenerated electrons (e⁻) and superoxide radical (·O₂⁻) were critical active groups that had a significant role in the oxidative removal of NO. The in situ Fourier-transform infrared spectroscopy (in situ FTIR) showed that the photo-oxidation products were mainly NO₂⁻ and NO₃⁻. Based on the above experimental results, a possible photocatalytic mechanism was proposed. The electrons in Bi₄O₅Br₂ were excited by visible light. They jumped from the valence band (VB) of Bi₄O₅Br₂ to the conduction band (CB). Then, the photoelectrons transferred from the CB of Bi₄O₅Br₂ to the Ti₃C₂ surface, which significantly promoted the separation of the electron-hole pairs. Therefore, the photocatalytic efficiency of Ti₃C₂/Bi₄O₅Br₂ on NO was significantly improved. This study provided an effective method for preparing 2D/2D Ti₃C₂/Bi₄O₅Br₂ nanocomposites for the photocatalytic degradation of environmental pollutants, which has great potential in solving energy stress and environmental pollution.     

固态TiO2纳米太阳电池研究进展

本文介绍了固态TiO2纳米太阳电池的结构和工作有理，对近年来全固态纳米太阳电池，纳米TiO2膜、染料敏化剂的研究进展进行了综述。     

纳米SnO2的制备

ＳｎＯ２在陶瓷、气敏半导体材料及催化剂等方面被广泛应用［１］．纳米级的ＳｎＯ２因具有明显的表面效应而受到关注，其制备方法也受到重视［２］．纳米ＳｎＯ２的制备方法较多，有沉淀法［２］、水热法［３，４］、溶胶－凝胶法［５］、火焰合成法［６］等．然而要制备...     

基于1D/0D有序复合SnO2纳米晶的钙钛矿太阳能电池

通过水热前驱体中的功能添加剂调控一维(1D)纳米棒阵列疏密度,继而在纳米棒间隙沉积零维(0D)纳米颗粒,制备1D/0D有序的复合SnO2电子传输层(ETL),并组装高效、稳定的钙钛矿太阳能电池。系统研究前驱体中NaCl添加剂以及后续纳米颗粒的沉积对复合ETL的形貌结构、光谱性能及界面电荷过程的作用规律,探讨上述作用对电池光电性能的影响机制。前驱体中NaCl的加入使棒密度变小,从而使0D纳米颗粒顺利渗透到1D纳米棒间隙中,其对钙钛矿/ETL和钙钛矿/FTO界面复合的抑制作用是造成器件开路电压和填充因子增大的原因。在经2 mL饱和NaCl水溶液改性的1D电子传输层ETL-2Cl的基础上,继续沉积0D的纳米颗粒,制备得到新型1D/0D复合电子传输层ETL-2P,后者优良的电荷复合抑制作用(复合电阻是ETL-2Cl的2.9倍)和高效的电子抽提性能(抽提速率3.03×10^7 s^-1,抽提效率91.6%)促成了电池较优的光电性能(光电效率12.15%)。     

构建2D-2D TiO2纳米片/层状WS2异质结用以增强可见光响应光催化活性

自Fujishima等首次报道以来, TiO_2作为一种重要的光催化剂引起了人们的广泛关注.迄今为止,研究人员已经开发出了各种形貌的具有不同晶型结构的TiO_2,并用于光催化降解有机污染物.然而, TiO_2的宽禁带(3.2 eV)使其难以被可见光激活,导致对太阳光的利用效率低下.而且,在光催化反应中,低的量子效率无法满足实际应用.因此,开发具有可见光响应的高催化活性的TiO_2基催化剂具有重要意义.集成复合材料、纳米材料和界面的优势构建纳米复合材料已成为提高TiO_2光催化活性的重要策略. WS_2具有典型的类石墨烯层状结构和窄的带隙(1.35 eV),且其导带高于TiO_2的导带,适合作为助催化剂修饰TiO_2,使其具备可见光响应光催化活性.本文采用一步水热法,以二维(2D)TiO_2纳米片作基质材料,直接在其表面原位生长WS_2层,制得了2D-2D TiO_2纳米片/层状WS_2(TNS/WS_2)异质结. XRD及Raman结果表明,层状WS_2与TiO_2纳米片紧密结合在一起,且两者之间形成了W=O键.TEM结果显示,层状WS_2以面-面堆叠方式均匀地包覆在TiO_2纳米片表面,包覆层数约为4层.光催化性能测试结果表明,可见光照射下, TNS/WS_2异质结对RhB的光催化降解能力高于原始TiO_2纳米片和层状WS_2,光催化活性得到明显增强.紫外可见光谱试验结果显示,层状WS_2的引入极大地增强了异质结的光吸收性能. PL光谱测试表明, TNS/WS_2异质结具有更高效的载流子分离效率.为了进一步证实是光吸收性能的提升还是载流子分离效率的增强对光催化性能提起其主要作用,本文还研究了3D-2D TiO_2空心微球/层状WS_2(THS/WS_2)复合材料.结果表明, TNS/WS_2异质结比THS/WS_2复合材料具有更高效的光生电子和空穴的分离能力.从而证明了TiO_2纳米片与层状WS_2之间完美的2D-2D纳米界面和紧密的界面结合,显著增加了载流子分离效率,因此光催化活性得到明显提高.为了研究TNS/WS_2异质结光催化剂的光催化机理,采用重铬酸钾、草酸铵、叔丁醇和对苯醌作自由基猝灭剂进行了自由基捕捉剂实验.结果表明,空穴在RhB降解过程中起主要作用,超氧自由基起次要作用.基于自由基猝灭实验结果和带隙结构分析,提出了TNS/WS_2异质结对RhB的光催化机理为双转移光催化机理.可见,界面异质结工程化可能是制备高效和环境稳定的光催化剂的新思路     

吸附相反应技术制备纳米TiO2/SiO2复合材料

以SiO₂表面形成的吸附层为反应器,在载体表面制备了纳米TiO₂粒子.溶剂置换实验直接给出了吸附层的存在以及吸附层作为纳米反应器的实验证据,TEM,XRD和电子能谱分析表明,载体表面形成一层比较均匀的纳米粒子.初步探讨了温度和反应物浓度对产物分布的影响,分析了各种现象产生的可能成因.     

稀土掺杂纳米TiO_2的研究进展

在过去的几十年里,TiO_2纳米晶因为禁带较宽,对387.5 nm以下的紫外光有很强的吸收能力,光生载流子复合率高、无毒、廉价,且化学稳定性好等优点已在光电器件、光通信和环境等领域广泛的研究和应用。然而TiO_2因没有连续的或者丰富的能级来提供发光、发光性质单一等缺点限制了TiO_2的应用。本文总结了近几年稀土掺杂TiO_2纳米晶发光材料的研究工作,回顾了稀土掺杂TiO_2纳米晶的制备方法以及其在光电器件、光通信、光催化等方面的研究进展,并就稀土掺杂TiO_2研究中存在的问题和发展进行了思考和展望。     

羧基功能化石墨烯增强TiO2光催化产氢性能

The use of semiconductor photocatalysts (CdS, g-C₃N₄, TiO₂, etc.) to generate hydrogen (H₂) is a prospective strategy that can convert solar energy into hydrogen energy, thereby meeting future energy demands. Among the numerous photocatalysts, TiO₂ has attracted significant attention because of its suitable reduction potential and excellent chemical stability. However, the photoexcited electrons and holes of TiO₂ are easily quenched, leading to limited photocatalytic performance. Furthermore, graphene has been used as an effective electron cocatalyst in the accelerated transport of photoinduced electrons to enhance the H₂-production performance of TiO₂, owing to its excellent conductivity and high charge carrier mobility. For an efficient graphene-based photocatalyst, the rapid transfer of photogenerated electrons is extremely important along with an effectual interfacial H₂-production reaction on the graphene surface. Therefore, it is necessary to further optimize the graphene microstructures (functionalized graphene) to improve the H₂-production performance of graphene-based TiO₂ photocatalysts. The introduction of H₂-evolution active sites onto the graphene surface is an effective strategy for the functionalization of graphene. Compared with the noncovalent functionalization of graphene (such as loading Pt, MoS_x, and CoS_x on the graphene surface), its covalent functionalization can provide a strong interaction between graphene and organic molecules in the form of H₂-evolution active sites that are produced by chemical reactions. In this study, carboxyl-functionalized graphene (rGO-COOH) was successfully modified via ring-opening and esterification reactions on the TiO₂ surface by using an ultrasound-assisted self-assembly method to prepare a high-activity TiO₂/rGO-COOH photocatalyst. The Fourier transform infrared (FTIR) spectra, X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG) curves revealed the successful covalent functionalization of GO to rGO-COOH by significantly enhanced ―COOH groups in FTIR and increased peak area of carboxyl groups in XPS. A series of characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), XPS, and UV-Vis adsorption spectra, were performed to demonstrate the successful synthesis of TiO₂/rGO-COOH photocatalysts. The experimental data for the hydrogen-evolution rate showed that the TiO₂/rGO-COOH displayed an extremely high hydrogen-generation activity (254.2 μmol∙h⁻¹∙g⁻¹), which was 2.06- and 4.48-fold higher than those of TiO₂/GO and TiO₂, respectively. The enhanced photocatalytic activity of TiO₂/rGO-COOH is ascribed to the carboxyl groups of carboxyl-functionalized graphene, which act as effective hydrogen-generation active sites and enrich hydrogen ions owing to their excellent nucleophilicity that facilitates the interfacial hydrogen production reaction of TiO₂. This study provides novel insights into the development of high-activity graphene-supported photocatalysts in the hydrogen-generation field.      

基于密度泛函理论下H2S在单原子催化剂V/Ti2CO2上的分解机理研究

In-depth understanding of the mechanisms of hydrogen sulfide (H₂S) adsorption on catalysts during desulfurization from industrial waste gas streams is important for developing effective catalysts to be used in the decomposition of H₂S. In this work, the dissociation behavior of H₂S adsorbed on a single-atom catalyst (Ti or V-decorated Ti₂CO₂ surface) was investigated by performing density functional theory (DFT) calculations. The corresponding diffusion behavior revealed that Ti or V atoms could be dispersed on the Ti₂CO₂ monolayer, without aggregation in the form of single atoms. In addition, analyses of the partial density of states (PDOS), Hirshfeld charges, and electron density difference indicated that the decorated Ti or V atoms led to charge redistribution on the Ti₂CO₂ surface and significantly improved the interaction between the H₂S gas molecules and Ti₂CO₂, thereby enhancing the catalytic activity of V/Ti₂CO₂. In order to gain a deeper understanding of the mechanism of H₂S decomposition (H₂S → HS* + H* → H₂ + S*), a comparative analysis of the results for the decomposition of H₂S on the Ti/Ti₂CO₂ and V/Ti₂CO₂ surfaces was carried out. The catalytic dissociation behavior of H₂S is explained as follows: once H₂S is adsorbed on the V/Ti₂CO₂ or Ti/Ti₂CO₂ surface, it spontaneously dissociates into HS*/H* without any energy barrier on the catalyst surface. Subsequently, the V atoms would not only promote the cleavage of the H-S bond, but also play a major role in the formation of S atoms. Moreover, the rate-limiting step for the entire process proceeded on the Ti/Ti₂CO₂ surface with an energy barrier of 0.86 eV, while that for V/Ti₂CO₂ was 0.28 eV, indicating that the H₂S molecules easily dissociated into S and H₂ on the V/Ti₂CO₂ surface at room temperature. The reaction time for H₂S decomposition on the V/Ti₂CO₂ surface at 500 K was 65.79 ns, which was almost two orders of magnitude higher than that at room temperature. Thus, the decomposition of H₂S on the V-doped Ti₂CO₂ surface is associated very fast kinetics. Furthermore, the S atoms can form elemental sulfur with aggregation on the V/Ti₂CO₂ surface to promote recycling reactions. Compared with previously reported catalytic systems, the single-atom catalyst (SAC) V/Ti₂CO₂ catalyst has greater application prospects in terms of sustainable economy or removal efficiency for H₂S treatment. Our results suggest that V-doped Ti₂CO₂ is an excellent candidate for a highly effective non-noble metal catalyst applicable to H₂S decomposition.      

制备条件对MXene形貌、 结构与电化学性能的影响

以Ti₃AlC₂为原料, 采用LiF+HCl一步刻蚀-插层制备Ti₃C₂T_x, 进一步通过超声处理得到单层或少层的MXene. 利用X射线衍射(XRD)、 X射线光电子能谱(XPS)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)和电化学测试对样品的结构、 形貌和电化学性能进行了研究. 通过改变刻蚀剂的比例及超声剥离时间, 研究了不同刻蚀条件和剥离条件对二维晶体Ti₃C₂T_x的形貌、 结构和电化学性能的影响. 结果表明, 制备条件对MXene的片层结构和性能具有较大的影响. 当HCl浓度为6 mol/L, LiF与Ti₃AlC₂的摩尔比为7.5, 超声时间为1 h时, 所得MXene具有较小的晶格常数和较大的片层尺寸, 片层尺寸可达1 μm, 具有较多的表面含氧官能团, 电化学性能最佳, 在0.5 A/g的电流密度下, 质量比容量达到342 F/g, 当电流密度提高至20 A/g时, 质量比容量仍可保持244 F/g, 在1 A/g电流密度下循环10000周后, 容量仍能保留87%左右, 表现出较好的倍率性能与循环稳定性.     

MXene-碳黑/硫复合材料在锂硫电池一体式电极的研究

锂硫电池的实际能量密度不高和多硫化物（LiPSs）的穿梭效应等问题严重影响了该电池的实际应用。本文通过将二维的Ti₃C₂T_x Mxene纳米片与碳黑/硫（CB/S）材料进行混合,制备了Ti₃C₂T_x-CB/S正极材料并将其涂覆在商业隔膜（PP）上,最终获得了Ti₃C₂T_x-CB/S-PP一体式电极并用于锂硫电池。利用Ti₃C₂T_x纳米片对CB/S进行修饰,不仅能提高活性物质硫的导电性,还能对扩散的LiPSs进行物理阻挡和化学吸附。而一体式电极的设计有利于提高电池的能量密度。恒流充放电测试结果表明,Ti₃C₂T_x-CB/S-PP电极在0.1 C电流下的初始放电容量为1028.8 mAh·g^-1,高于不含Ti₃C₂T_x的CB/S-PP电极的896.8 mAh·g^-1。Ti₃C₂T_x-CB/S-PP电极还展示出了比基于传统铝箔集流体的Ti₃C₂T_x-CB/S-Al电极更好的循环稳定性,前者在0.5 C下400圈长循环测试中的每圈衰减率为0.072%,而后者则为更高的0.10%。本文利用Ti₃C₂T_x-CB/S构建一体式电极的策略为实现高性能和高能量密度的锂硫电池提供了新的研究方向。     

新型Ti3C2 MXene的化学制备及基于MXene忆阻器特性与机理

阻变器件是一种微电子器件,具有阻值可在两个甚至两个以上的阻态之间重复变化的特点。忆阻器作为新型的阻变器件,具有可连续变化的丰富阻态。近年来因其具备简单的二端结构、高集成度以及低工作电压等特性,在新型非易失性存储以及构建神经形态系统等方面被广泛研究。但其在实现应用的过程中仍存在着稳定性较差等问题。近期一些工作证明了二维材料如氧化石墨烯在优化忆阻器性能方面具备良好的应用潜力。MXene是一种具备类似石墨烯结构的新型二维过渡金属碳/氮化物,因其具备二维层状结构显现出特殊的力学以及电学特性,有望应用于忆阻器中以提高器件的电学性能。在本文中,我们通过化学湿法刻蚀制备了Ti₃C₂粉末,通过旋涂工艺在忆阻器结构中引入Ti₃C₂薄膜。Ti₃C₂ MXene与SiO₂同时作为忆阻器阻变层,制备了Cu/Ti₃C₂/SiO₂/W结构的忆阻器,并且对其相关电学特性进行了探究。在该器件上,通过实验测得忆阻器典型的开关特性曲线并在双向直流电压下针对高、低阻态的可重复性、稳定性进行了实验。结果表明该器件能够在100个扫描循环过程中保持稳定的高、低阻态达到10⁴ s以上。同时,该器件状态能够受脉冲电压调节,实现突触间典型的双脉冲易化行为。实验结果表明基于Ti₃C₂ MXene的忆阻器将有望应用于构建新兴存储设备以及人工神经形态系统。     

二维/一维BiOBr0.5Cl0.5/WO3 S型异质结助力光催化CO2还原

S型异质结不但可以提高载流子的分离效率,还可以维持较强的氧化还原能力。因此,构建S型异质是提高光催化二氧化碳还原反应的有效途径。本研究通过静电自组装法构建了具有近红外光响应(> 780 nm)的二维BiOBr_0.5Cl_0.5纳米片和一维WO₃纳米棒S型异质结光催化剂,并用于高效还原二氧化碳。能带位置和界面电子相互作用的综合分析表明：在光催化二氧化碳还原反应过程中,BiOBr_0.5Cl_0.5/WO₃遵循S型电子转移路径;不仅提高了载流子的高效分离,还维持了两相(BiOBr_0.5Cl_0.5和WO₃)较高的氧化还原能力。此外,二维纳米片/一维纳米棒的结构使得半导体之间具备良好的界面接触,有利于载流子的分离,且暴露更多的活性位点,最终提高催化效率。结果显示,BiOBr_0.5Cl_0.5/WO₃异质结催化剂表现出较高的CO₂还原能力和CO选择性,CO的产率高达16.68 μmol∙g^-1∙h^-1,分别是BiOBr_0.5Cl_0.5的1.7倍和WO₃的9.8倍。本工作为构建S型二维/一维异质结光催化剂高效还原二氧化碳提供了新的思路。     

Bimetallic Sulfide/Sulfur Doped T3C2Tx MXene Nanocomposites as High-performance Anode Materials for Sodium-ion Batteries

The application of transition metal dichalcogenides(TMDs) as anode materials in sodium-ion batteries (SIBs) has been hindered by low conductivity and poor cyclability. Herein, we report the synthesis of Co_xFe_1-xS₂ bimetallic sulfide/sulfur-doped Ti₃C₂ MXene nanocomposites(Co_xFe_1-xS₂@S-Ti₃C₂) by a facile co-precipitation process and thermal-sulfurization reaction. The interconnected 3D frameworks consisting of MXene nanosheets can effectively buffer the volume change and enhance the charge transfer. In particular, sulfur-doped MXene nanosheets provide rich active sites for sodium storage and restrain sulfur loss during charging/discharging processes, leading the increase of specific capacity and cycling the stability of anode materials. As a result, Co_xFe_1-xS₂@S-Ti₃C₂ anodes exhibited high capacity, high rate capability and long cycle life(399 mA·h/g at 5 A/g with an 94% capacity retention after 600 cycles).     

Pd修饰对Cd0.8Zn0.2S/SiO2光催化甘油水溶液制氢性能的影响

用等体积浸渍法制备了不同Pd负载量的Pd/Cd_0.8Zn_0.2S/SiO₂光催化材料,采用XRD、H₂-TPR、XPS、UV-vis DRS和光催化反应评价等方法对光催化材料的表面结构、光吸收性能以及光催化甘油水溶液制氢反应性能进行了考察。研究结果表明,ZnS与CdS在SiO₂表面形成了Cd_0.8Zn_0.2S固溶体,金属Pd负载未对固溶体Cd_0.8Zn_0.2S/SiO₂的结构造成影响;金属Pd修饰明显地提高了原固溶体的光响应性能,拓展了其吸光域,增强了吸光效率。金属Pd修饰后,Cd_0.8Zn_0.2S/SiO₂的光解甘油水溶液产氢速率显著提高,Pd负载量为0.5%的Pd/Cd_0.8Zn_0.2S/SiO₂具有最佳的光催化甘油水溶液制氢性能,其在紫外光照射下的氢气生成速率为831 μmol/h,较未负载时提高了近四倍;模拟太阳光下为153 μmol/h,较未负载时提高了近两倍。     

具有水下超疏油性能的MXene高效油水分离膜

基于二维材料MXene(Ti₃C₂T_x)的化学组成和纳米片状结构, 在不锈钢网上制备了具有MXene微纳结构表面的新型亲水和水下超疏油分离膜. 对于不同类型的油-水混合物, 该膜材料可实现重力驱动的高效油水分离, 收集的水中残油量小于4 mg/L, 具有高分离效率(>99.99%), 水通量高达57.52 L·m^-2·s^-1. 此外, 经高温处理和多种有机溶剂浸泡后MXene膜仍具有高效的油水分离性能, 并表现出优异的稳定性和循环性.