Supporting Ultrathin ZnIn2S4 Nanosheets on Co/N‐Doped Graphitic Carbon Nanocages for Efficient Photocatalytic H2 Generation

Ultrathin ZnIn₂S₄ nanosheets (NSs) are grown on Co/N‐doped graphitic carbon (NGC) nanocages, composed of Co nanoparticles surrounded by few‐layered NGC, to obtain hierarchical Co/NGC@ZnIn₂S₄ hollow heterostructures for photocatalytic H₂ generation with visible light. The photoredox functions of discrete Co, conductive NGC, and ZnIn₂S₄ NSs are precisely combined into hierarchical composite cages possessing strongly hybridized shell and ultrathin layered substructures. Such structural and compositional virtues can expedite charge separation and mobility, offer large surface area and abundant reactive sites for water photosplitting. The Co/NGC@ZnIn₂S₄ photocatalyst exhibits outstanding H₂ evolution activity (e.g., 11270 µmol h^?1 g^?1) and high stability without engaging any cocatalyst.     

Spatial Specific Janus S-Scheme Photocatalyst with Enhanced H2O2 Production Performance

Photocatalytic oxygen reduction reaction (ORR) for H₂O₂ production in the absence of sacrificing agents is a green approach and of great significance, where the design of photocatalysts with high performance is the central task. Herein, a spatial specific S-scheme heterojunction design by introducing a novel semiconducting pair with a S-scheme mechanism in a purpose-designed Janus core–shell-structured hollow morphology is reported. In this design, TiO₂ nanocrystals are grown inside the inner wall of resorcinol-formaldehyde (RF) resin hollow nanocakes with a reverse bumpy ball morphology (TiO₂@RF). The S-scheme heterojunction preserves the high redox ability of the TiO₂ and RF pair, the spatial specific Janus design enhances the charge separation, promotes active site exposure, and reduces the H₂O₂ decomposition to a large extent. The TiO₂@RF photocatalyst shows a high H₂O₂ yield of 66.6 mM g⁻¹ h⁻¹ and solar-to-chemical conversion efficiency of 1.11%, superior to another Janus structure (RF@TiO₂) with the same heterojunction but a reversed Janus spatial arrangement, and most reported photocatalysts under similar reaction conditions. The work has paved the way toward the design of next-generation photocatalysts for green synthesis of H₂O₂ production.     

Spatially Separating Redox Centers on Z‐Scheme ZnIn2S4/BiVO4 Hierarchical Heterostructure for Highly Efficient Photocatalytic Hydrogen Evolution

Photocatalysis technology using solar energy for hydrogen (H₂) production still faces great challenges to design and synthesize highly efficient photocatalysts, which should realize the precise regulation of reactive sites, rapid migration of photoinduced carriers and strong visible light harvest. Here, a facile hierarchical Z‐scheme system with ZnIn₂S₄/BiVO₄ heterojunction is proposed, which can precisely regulate redox centers at the ZnIn₂S₄/BiVO₄ hetero‐interface by accelerating the separation and migration of photoinduced charges, and then enhance the oxidation and reduction ability of holes and electrons, respectively. Therefore, the ZnIn₂S₄/BiVO₄ heterojunction exhibits excellent photocatalytic performance with a much higher H₂‐evolution rate of 5.944 mmol g^?1 h^?1, which is about five times higher than that of pure ZnIn₂S₄. Moreover, this heterojunction shows good stability and recycle ability, providing a promising photocatalyst for efficient H₂ production and a new strategy for the manufacture of remarkable photocatalytic materials.     

不同晶相MnS制备及光解H2S制氢性能研究

采用溶剂热法成功制备了具有立方结构的α-MnS和六方结构的γ-MnS。通过X射线衍射(XRD), 扫描电子显微镜(SEM), 透射电子显微镜(TEM)、高分辨透射电镜(HRTEM)、选区电子衍射(SAED)和紫外-可见吸收光谱(UV-Vis), 对样品的物相组成、显微形貌、光学性质进行了研究, 并对不同晶相MnS在可见光(λ > 420 nm)和全光谱下光解H₂S制氢性能进行了研究。结果表明: α, γ-MnS在可见光下都具有光解H₂S制氢活性, 且相比于热力学稳定相的α-MnS (4.24 μmol/(g·h)), 亚稳态的γ-MnS (23.38 μmol/(g·h))具有更好的催化性能。相对于可见光, α, γ-MnS在全光谱下的产氢速率明显提高, 其中γ-MnS在全光谱下具有最大的光解H₂S制氢活性, 其产氢速率可达 2272.69 μmol/(g·h)。值得注意的是, 在6 h的光催化测试过程中, α, γ-MnS都展示较好的抗光腐蚀能力和光催化稳定性。此外, 对α, γ-MnS光催化分解H₂S制氢机理进行了分析, 通过对α, γ-MnS光电化学性质的研究, 对其光催化活性存在差异的原因进行了探讨。     

Heterostructure of 1D Ta3N5 Nanorod/BaTaO2N Nanoparticle Fabricated by a One‐Step Ammonia Thermal Route for Remarkably Promoted Solar Hydrogen Production

Heterostructures are widely fabricated for promotion of photogenerated charge separation and solar cell/fuel production. (Oxy)nitrides are extremely promising for solar energy conversion, but the fabrication of heterostructures based on nitrogen‐containing semiconductors is still challenging. Here, a simple ammonia thermal synthesis of a heterostructure (denoted as Ta₃N₅/BTON) composed of 1D Ta₃N₅ nanorods and BaTaO₂N (BTON) nanoparticles (0D), which is demonstrated to result in a remarkable increase in photogenerated charge separation and solar hydrogen production from water, is introduced. As analyzed and discussed, the Ta₃N₅/BTON heterostructure is type II and tends to create intimate interfaces between the 1D nanorods and 0D nanoparticles. The 1D Ta₃N₅ nanorods are demonstrated to transfer electrons along the rod orientation direction. Furthermore, the intimate interfaces of the heterostructure are believed to originate from the similar Ta‐based octahedron units of Ta₃N₅ and BTON. All of the above features are expected to integrally endow increased photoinduced charge separation and one order of magnitude higher solar overall water splitting activity with respect to counterpart systems. These results may open a new avenue to fabricate heterostructures on the basis of nitrogen‐containing semiconductors that is extremely promising for solar energy conversion.     

Construction of hierarchical FeIn2S4/BiOBr S-scheme heterojunction with enhanced visible-light photocatalytic performance for antibiotics degradation

Constructing heterojunction provides a promising tactic to improve the photocatalytic efficiency of catalysts. In this paper, hierarchical FeIn₂S₄/BiOBr heterostructure photocatalysts were prepared by facile two step methods and applied to effectively remove ciprofloxacin (CIP) and tetracycline (TC) under visible light. Compared to single catalyst, FeIn₂S₄/BiOBr hybrids display significantly improved photocatalytic activity. Among the series, 6 wt% FeIn₂S₄/BiOBr shows the optimal photocatalytic performance, where the degradation efficiencies of TC and CIP are 3.15 and 2.88 times greater than pure BiOBr, respectively. Such an improvement could arise from the S-scheme heterojunctions and unique hierarchical structures, which brings stronger light absorption, higher photoexcited charge separation efficiency and superior redox ability. Furthermore, 6 wt% FeIn₂S₄/BiOBr composite exhibits excellent stability and reusability. Radical capture experiments and EPR analyses uncover that O₂^–, h⁺ and OH are primarily reactive substances during photocatalytic removal of TC. The products of TC were detected by LC-MS analyses and possible decomposition paths are proposed. Eventually, a possible photodegradation mechanism over FeIn₂S₄/BiOBr S-scheme heterojunction is proposed. These findings supply new perspective for the simple synthesis of S-scheme photocatalysts with promising applications in environment remediation.     

可见光下光催化分解水制氢的研究进展

利用太阳能驱动光催化反应制备氢气成为了目前的研究热点。综述了近年来在可见光下光催化分解水制氢的研究进展,着重介绍了固溶体光催化剂、非金属化合物型光催化剂、Z型光催化系统及新型助催化剂的最新研究成果,并展望了光催化制氢的发展。     

S型异质结BiOBr/ZnMoO4的构建及光催化降解性能研究

光催化被广泛用于去除水中的难降解有机污染物,但是由于光生电子和空穴的复合率高,抑制了半导体光催化剂的催化活性。本研究通过简便的溶剂热法成功制备了一种BiOBr/ZnMoO₄复合材料。通过结构分析、原位XPS、功函数测试、自由基捕获及电子顺磁共振(ESR)实验等证实了BiOBr/ZnMoO₄复合材料形成了S型异质结。实验结果表明,适当ZnMoO₄含量的BiOBr/ZnMoO₄异质结可以显著提高BiOBr的光催化性能。与纯BiOBr、ZnMoO₄相比,质量分数15%BiOBr/ZnMoO₄在可见光下表现出最佳的光催化活性,双酚A的光催化降解率达到85.3%(90min),环丙沙星的光降解速率常数分别是BiOBr的2.6倍和ZnMoO₄的484倍。这可归因于BiOBr和ZnMoO₄之间形成了紧密的界面结合和S型异质结,使得光生载流子可以实现有效的空间分离和转移。这项工作为定向合成Bi基S型异质结复合光催化材料提供了一种...     

Visible light active ZnIn2S4/g-C3N4 heterostructure nanocomposite photoelectrode for efficient photoelectrochemical water splitting activity

Hexagonal zinc indium sulfide coupled g-C₃N₄ (H-ZnIn₂S₄/g-C₃N₄) nanocomposites were synthesized using chemisorption method and its performance towards photoelectrochemical water splitting activity was studied. The H-ZnIn₂S₄/g-C₃N₄ (H-ZIS/CN) nanocomposites exhibited ∼ 1.9 times enhanced photoelectrochemical performance as compared to the H-ZnIn₂S₄. The enhancement in the PEC water splitting activity of H-ZIS/CN nanocomposite is ascribed to the formation of type-II heterojunction which resulted in improved separation of photogenerated charge carriers and faster transfer of charges at the photoelectrode/electrolyte interface. The electrochemical impedance study and Mott-Schottky supported these results. Moreover, during photoelectrochemical reactions, H-ZIS/CN nanocomposites showed tremendous stability under visible light. A potential mechanism of the enhanced photoelectrochemical activity of H-ZIS/CN nanocomposites was proposed and endorsed by the PEC results. This study demonstrates that establishing a heterostructure system by coupling a ternary chalcogenide semiconductor with a conducting polymer is an effective strategy for PEC water splitting applications.     

粉煤灰基纳米复合材料的制备及光催化分解水产氢性能研究

采用一种经济可行的方法制备粉煤灰基CdS／Al-MCM-41介孔纳米复合材料,通过碱融法从粉煤灰中提取硅源和铝源,室温下模板组装纳米复合材料,小角XRD和高分辨率TEM结果表明,介孔分子筛Al-MCM-41的平均孔径约3．0nm,CdS颗粒均匀地分散于Al-MCM-41的孔道内;UV—vis漫反射光谱结果表明,CdS／Al-MCM-41纳米复合材料在波长约521nm处出现较强吸收边;荧光光谱结果表明,CdS与Al-MCM-41复合有效地降低了光生电子与空穴的复合几率;在可见光照射下,CdS／Al-MCM-41显示出较高的产H2活性,归因于CdS颗粒和介孔分子筛Al-MCM-41之间的协同作用所致。     

RuO2/ZrO2/TaON复合光催化材料的制备及光解水制氢性能

采用控制水解法制备了细颗粒的ZrO₂/Ta₂O₅复合氧化物粉体, 在氨气流量为90 mL/min、850℃下氮化10 h获得ZrO₂/TaON, 用浸渍法制备含助催化剂RuO₂的复合光催化剂。用XRD、SEM、TEM和UV-Vis漫反射光谱等对所制备的光催化材料进行了表征, ZrO₂、RuO₂的晶粒尺寸约为10 nm,TaON的晶粒尺寸约为25 nm, 复合光催化剂可以吸收波长≤500 nm的可见光。ZrO₂的引入降低了氮化生成TaON的缺陷密度, 提高了TaON的比表面积。光电流及光催化分解水制氢反应定量评价了复合材料的光催化性能, RuO₂含量为2.0wt%时复合光催化剂活性最高, 0.6 V偏压下光电流密度为0.6 mA/cm², 产氢速率为6.0 μmol/h。     

In Situ Formation ZnIn2S4/Mo2TiC2 Schottky Junction for Accelerating Photocatalytic Hydrogen Evolution Kinetics: Manipulation of Local Coordination and Electronic Structure

Regulating electronic structures of the active site by manipulating the local coordination is one of the advantageous means to improve photocatalytic hydrogen evolution (PHE) kinetics. Herein, the ZnIn₂S₄/Mo₂TiC₂ Schottky junctions are designed to be constructed through the interfacial local coordination of In³⁺ with the electronegative  O terminal group on Mo₂TiC₂ based on the different work functions. Kelvin probe force microscopy and charge density difference reveal that an electronic unidirectional transport channel across the Schottky interface from ZnIn₂S₄ to Mo₂TiC₂ is established by the formed local nucleophilic/electrophilic region. The increased local electron density of Mo₂TiC₂ inhibits the backflow of electrons, boosts the charge transfer and separation, and optimizes the hydrogen adsorption energy. Therefore, the ZnIn₂S₄/Mo₂TiC₂ photocatalyst exhibits a superior PHE rate of 3.12 mmol g⁻¹ h⁻¹ under visible light, reaching 3.03 times that of the pristine ZnIn₂S₄. This work provides some insights and inspiration for preparing MXene-based Schottky catalysts to accelerate PHE kinetics.     

Highly Stable Phosphonate-Based MOFs with Engineered Bandgaps for Efficient Photocatalytic Hydrogen Production

Photoactive metal–organic frameworks (MOFs) represent one of the most promising materials for photocatalytic hydrogen production, but phosphonate-based MOFs have remained largely underdeveloped compared to other conventional MOFs. Herein, a photocatalyst of 1D titanium phosphonate MOF is designed through an easy and scalable stirring hydrothermal method. Homogeneous incorporation of organophosphonic linkers can narrow the bandgap, which is due to the strong electron-donating ability of the  OH functional group that can efficiently shift the top of the valence band, moving the light absorption to the visible portion of the spectrum. In addition, the unique 1D nanowire topology enhances the photoinduced charge carrier transport and separation. Accordingly, the titanium phosphonate nanowires deliver remarkably enhanced photocatalytic hydrogen evolution activity under irradiation of both visible light and a full-spectrum simulator. Such concepts of engineering both nanostructures and electronic states herald a new paradigm for designing MOF-based photocatalysts.     

光催化分解水制氢体系助催化剂研究进展

煤、石油、天然气等不可再生能源的消耗导致环境污染日益严重,开发和使用清洁的可再生能源迫在眉睫。利用太阳能光催化分解水制氢被认为是解决化石能源紧缺和环境污染问题的有效途径之一。光催化分解水制氢体系非常复杂,助催化剂是影响催化剂光催化效率的一个关键因素,它的引入可以有效提高催化剂的光催化活性和氢气产生速率,因此,开发廉价高效的助催化剂已逐渐成为本领域的研究热点。本文结合光催化分解水制氢原理,简要介绍了助催化剂的作用,对近年来光催化分解水产氢助催化剂的种类和研究内容进行了总结,分析和讨论了几类重要助催化剂的特点及作用机理,并对助催化剂的发展进行了展望,以期为新型高效光催化制氢材料的设计提供参考。     

Spontaneous photoelectric field-enhancement effect prompts the low cost hierarchical growth of highly ordered heteronanostructures for solar water splitting

In this study, a potentially universal new strategy is reported for the large-scale, low-cost fabrication of visible-light-active highly ordered heteronanostructures based on the spontaneous photoelectric-field-enhancement effect inherent in pyramidal morphology. The hierarchical vertically oriented arrayed structures comprise an active molecular co-catalyst at the apex of a visible-light-active large band gap semiconductor for low-cost solar water splitting in a neutral aqueous medium without the use of a sacrificial agent.

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S、RE共掺杂TiO2的制备及其可见光分解水制氢性能

采用溶胶-凝胶法制备了系列稀土(La、Eu、Nd、Tb、Er)和硫共掺杂TiO2光催化剂RE/S/TiO2。通过紫外-可见(UV-Vis)漫反射、X射线衍射(XRD)对催化剂进行了表征。以EDTA为电子给体,考察了光催化剂在可见光照射下的制氢活性。研究结果表明,S/TiO2具有可见光活性,稀土掺杂进一步提高了S/TiO2可见光活性,其活性顺序依次为Eu/S/TiO2>La/S/TiO2>Nd/S/TiO2>Tb/S/TiO2>Er/S/TiO2。与纯TiO2和S/TiO2光催化剂相比,稀土掺杂使催化剂的粒径减小,晶格畸变应力增大,从而提高了催化剂可见光制氢活性。     

Graphitic-C3N4/ZnCr-layered double hydroxide 2D/2D nanosheet heterojunction: Mesoporous photocatalyst for advanced oxidation of azo dyes with in situ produced H2O2

In this study the constructional modification of Graphitic carbon nitride nanosheet (GCN-ns) has been made with the aid of ZnCr layered double hydroxide (ZC-LDH) in a unique 2D-2D structure to enhance its visible light absorption. Optical and morphological study presents successful incorporation of ZC-LDH on the surface of GCN-ns. Through adjusting of GCN-ns by ZC-LDH lower recombination rate of e^?/h⁺ pairs, longer lifetimes and an increase in contamination reduction was brought out. The binary nanocomposite was employed to effectively degrade Rhodamine B under UV/vis light irradiation. The improvement in photocatalytic abilities was proven to be related to in situ self-production of H₂O₂ on GCN-ns/ZC-LDH surface by Xe light irradiation which in return accounts for additional hydroxide radical generation. Radical quenching experiments specified the main active species involved while the consequent step-scheme (S-scheme) charge transfer mechanism was proposed.