Integration of Multiple Plasmonic and Co‐Catalyst Nanostructures on TiO2 Nanosheets for Visible‐Near‐Infrared Photocatalytic Hydrogen Evolution

Utilization of visible and near‐infrared light has always been the pursuit of photocatalysis research. In this article, an approach is developed to integrate dual plasmonic nanostructures with TiO₂ semiconductor nanosheets for photocatalytic hydrogen production in visible and near‐infrared spectral regions. Specifically, the Au nanocubes and nanocages used in this work can harvest visible and near‐infrared light, respectively, and generate and inject hot electrons into TiO₂. Meanwhile, Pd nanocubes that can trap the energetic electrons from TiO₂ and efficiently participate in the hydrogen evolution reaction are employed as co‐catalysts for improved catalytic activity. Enabled by this unique integration design, the hydrogen production rate achieved is dramatically higher than those of its counterpart structures. This work represents a step toward the rational design of semiconductor–metal hybrid structures for broad‐spectrum photocatalysis.     

Progressive Design of Plasmonic Metal–Semiconductor Ensemble toward Regulated Charge Flow and Improved Vis–NIR‐Driven Solar‐to‐Chemical Conversion

Surface plasmon resonance (SPR)‐mediated photocatalysis without the bandgap limitations of traditional semiconductor has aroused significant attention in solar‐to‐chemical energy conversion. However, the photocatalytic efficiency barely initiated by the SPR effects is still challenged by the low concentration and ineffective extraction of energetic hot electrons, slow charge migration rates, random charge diffusion directions, and the lack of highly active sites for redox reactions. Here, the tunable, progressive harvesting of visible‐to‐near infrared light (vis–NIR, λ > 570 nm) by designing plasmonic Au nanorods and metal (Au, Ag, or Pt) nanoparticle codecorated 1D CdS nanowire (1D CdS NW) ensemble is reported. The intimate integration of these metal nanostructures with 1D CdS NWs promotes the extraction and manipulated directional separation and migration of hot charge carriers in a more effective manner. Such cooperative synergy with tunable control of interfacial interaction, morphology optimization, and cocatalyst strategy results in the distinctly boosted performance for vis–NIR‐driven plasmonic photocatalysis. This work highlights the significance of rationally progressive design of plasmonic metal–semiconductor‐based composite system for boosting the regulated directional flow of hot charge carrier and thus the more efficient use of broad‐spectrum solar energy conversion.     

0D–2D Quantum Dot: Metal Dichalcogenide Nanocomposite Photocatalyst Achieves Efficient Hydrogen Generation

Hydrogen generation via photocatalysis‐driven water splitting provides a convenient approach to turn solar energy into chemical fuel. The development of photocatalysis system that can effectively harvest visible light for hydrogen generation is an essential task in order to utilize this technology. Herein, a kind of cadmium free Zn–Ag–In–S (ZAIS) colloidal quantum dots (CQDs) that shows remarkably photocatalytic efficiency in the visible region is developed. More importantly, a nanocomposite based on the combination of 0D ZAIS CQDs and 2D MoS₂ nanosheet is developed. This can leverage the strong light harvesting capability of CQDs and catalytic performance of MoS₂ simultaneously. As a result, an excellent external quantum efficiency of 40.8% at 400 nm is achieved for CQD‐based hydrogen generation catalyst. This work presents a new platform for the development of high‐efficiency photocatalyst based on 0D–2D nanocomposite.     

Enhanced visible light photocatalytic activity of novel Pt/C-doped TiO2/PtCl4 three-component nanojunction system for degradation of toluene in air

C-doped TiO(2) nanoparticles prepared by partial oxidation of TiC were modified with Pt species by impregnation-calcination method in order to enhance the visible light photocatalytic activity. The physicochemical properties of as-prepared samples were characterized by various techniques in detail. The results indicated that a novel Pt/C-doped TiO(2)/PtCl(4) three-component nanojunction system was formed, where C-doped TiO(2) and PtCl(4) behaved as two visible light responsive components, and Pt metal as electron-transfer system. The three-component nanojunctioned photocatalyst system exhibited six times higher visible light activity than that of the pristine C-doped TiO(2) in degradation of toluene in air. The dramatically enhanced activity can be attributed to the increased utilization of visible light, the enhanced charge carrier separation and transfer process. Further more, the band structure and photocatalysis mechanism over the three-component nanojunction system was proposed and discussed. This work may provide new insights into the design of novel multi-component photocatalyst system with efficient visible light activity.     

Dual‐Hole Excitons Activated Photoelectrolysis in Neutral Solution

II–VI semiconductors exhibit unique behaviors that can generate dual‐holes (“heavy and light”), but the application in photocatalysis is still missing. Herein, an empirical utilization of light/heavy holes in a hybrid metal cluster‐2D semiconductor nanoplatelets is reported. This hybrid material can boost the hole‐transfer at the surface and suppress the recombination. Different roles are enacted by light‐holes and heavy‐holes, in which the light‐holes with higher energy and mobility can facilitate the slow kinetics of water oxidation and further reduce the onset voltage, while the massive heavy‐holes can increase the resulting photocurrent by about five times, achieving a photocurrent of 2 mA cm^?2 at 1.23 V versus RHE under AM 1.5 G illumination in nonsacrificial neutral solution. These strategies can be the solutions for photoelectrolysis and be beneficial for sustainable development in solar conversion.     

界面电荷快速转移提升铜修饰氧化钨光催化性能(英文)

非贵金属修饰可以有效增强单一半导体的光生电荷分离,进而改善光催化活性。采用一种简单的抗坏血酸室温还原法制备了WO₃-Cu复合光催化材料,并用不同表征手段对其组成和结构进行了表征。结果显示, Cu颗粒沉积在WO₃纳米立方的表面,在模拟太阳光照射下,与WO₃相比, WO₃-Cu复合材料具有良好的光催化降解刚果红的能力。活性物种捕捉实验以及顺磁共振结果表明,光诱导产生的空穴、羟基自由基、超氧自由基阴离子等活性物种在刚果红降解过程中起主要作用。根据光电化学测试结果,WO₃在光催化过程中产生的电子快速转移向Cu颗粒,可以有效分离光生电子–空穴对并加快光生载流子迁移,进而有利于光催化反应的发生,从而使WO₃表现出较高的光催化活性。     

Dual Cocatalysts in TiO2 Photocatalysis

Semiconductor photocatalysis is recognized as a promising strategy to simultaneously address energy needs and environmental pollution. Titanium dioxide (TiO₂) has been investigated for such applications due to its low cost, nontoxicity, and high chemical stability. However, pristine TiO₂ still suffers from low utilization of visible light and high photogenerated‐charge‐carrier recombination rate. Recently, TiO₂ photocatalysts modified by dual cocatalysts with different functions have attracted much attention due to the extended light absorption, enhanced reactant adsorption, and promoted charge‐carrier‐separation efficiency granted by various cocatalysts. Recent progress on the component and structural design of dual cocatalysts in TiO₂ photocatalysts is summarized. Depending on their components, dual cocatalysts decorated on TiO₂ photocatalysts can be divided into the following categories: bimetallic cocatalysts, metal–metal oxide/sulfide cocatalysts, metal–graphene cocatalysts, and metal oxide/sulfide–graphene cocatalysts. Depending on their architecture, they can be categorized into randomly deposited binary cocatalysts, facet‐dependent selective‐deposition binary cocatalysts, and core–shell structural binary cocatalysts. Concluding perspectives on the challenges and opportunities for the further exploration of dual cocatalyst–modified TiO₂ photocatalysts are presented.     

光解水制氢半导体光催化材料的研究进展

自从Fujishima-Honda效应发现以来,科学研究者一直努力试图利用半导体光催化剂光分解水来获得既可储存而又清洁的化学能--氢能.近一二十年来,光催化材料的研究经历了从简单氧化物、复合氧化物、层状化合物到能响应可见光的光催化材料.本文重点描述了这些光催化材料的结构和光催化特性,阐述了该课题的意义和今后的研究方向.     

氮掺杂纳米TiO2光催化材料的制备及表征分析

以钛酸丁酯为钛源,尿素为氮源,采用溶胶——凝胶法制备纳米TiO2胶体。通过XRD、FI-IR、TG/DTG、UV-VisDRS等分析方法发现,氮掺杂对TiO2的晶型转化起抑制作用;紫外-可见光吸收光谱的分析结果表明,氮掺杂纳米TiO2可有效增强其紫外光区和可见光区吸收性能,拓展了纳米TiO2的光响应波长范围,提高了其光催化性能。     

Coupling Solar Energy into Reactions: Materials Design for Surface Plasmon‐Mediated Catalysis

Enabled by surface plasmons, noble metal nanostructures can interact with and harvest incident light. As such, they may serve as unique media to generate heat, supply energetic electrons, and provide strong local electromagnetic fields for chemical reactions through different mechanisms. This solar‐to‐chemical pathway provides a new approach to solar energy utilization, alternative to conventional semiconductor‐based photocatalysis. To provide readers with a clear picture of this newly recognized process, this review presents coupling solar energy into chemical reactions through plasmonic nanostructures. It starts with a brief introduction of surface plasmons in metallic nanostructures, followed by a demonstration of tuning plasmonic features by tailoring their physical parameters. Owing to their tunable plasmonic properties, metallic materials offer a platform to trigger and drive chemical reactions at the nanoscale, as systematically overviewed in this article. The design rules for plasmonic materials for catalytic applications are further outlined based on existing examples. At the end of this article, the challenges and opportunities for further development of plasmonic‐mediated catalysis toward energy and environmental applications are discussed.     

Cyclic performance and photo-induced crystalline growth of nanostructured AgI/TiO2 visible light photocatalyst

Nanostructured AgI/TiO2 visible light photocatalyst was prepared with AgNO3, KI, and Ti(OBu)4 as precursors. The photocatalyst was used repeatedly to degrade methylene blue and methyl orange in water with visible light irradiation. Though a high photocatalytic efficiency was observed for the photocatalyst in the first cycle, the photocatalytic efficiency was found to decrease dramatically in subsequent cycles. X-ray diffraction and SEM analyses revealed an obvious crystalline growth of AgI in AgI/TiO2 nanocomposite after photocatalysis or visible light irradiation. It was proposed that photo-induced crystalline growth had occurred to AgI in the course of photocatalysis and resulted in dramatic decrease in the photocatalytic efficiency of the photocatalyst. Photo-induced crystalline growth may be a limiting factor for the lifetime of photocatalysts and should be examined as an important aspect of photostability when new photocatalysts are developed.     

一种具有微纳孔隙结构的二氧化钛多孔膜层光催化系统

采用溶胶-凝胶法配合以离子注入的方式,研制了一种具有纳米和亚微米(零点几个微米)孔隙结构的锐钛矿相二氧化钛光催化膜。首先通过常规的溶胶-凝胶法制得密实的二氧化钛膜层,然后采用具有一定动能的Fe离子轰击膜层,从而在膜层中形成大量的微纳孔隙。这些微纳孔隙明显提高了原膜层的比表面积。光催化降解甲基橙溶液的实验结果表明,无论是在紫外光下还是在可见光下,所得多孔膜层的光催化效果均优于未造孔的二氧化钛膜层。     

Single Pt Atoms Confined into a Metal–Organic Framework for Efficient Photocatalysis

It is highly desirable yet remains challenging to improve the dispersion and usage of noble metal cocatalysts, beneficial to charge transfer in photocatalysis. Herein, for the first time, single Pt atoms are successfully confined into a metal–organic framework (MOF), in which electrons transfer from the MOF photosensitizer to the Pt acceptor for hydrogen production by water splitting under visible‐light irradiation. Remarkably, the single Pt atoms exhibit a superb activity, giving a turnover frequency of 35 h^?1, ≈30 times that of Pt nanoparticles stabilized by the same MOF. Ultrafast transient absorption spectroscopy further unveils that the single Pt atoms confined into the MOF provide highly efficient electron transfer channels and density functional theory calculations indicate that the introduction of single Pt atoms into the MOF improves the hydrogen binding energy, thus greatly boosting the photocatalytic H₂ production activity.     

Supramolecular Energy Materials

Self-assembly is a bioinspired strategy to craft materials for renewable and clean energy technologies. In plants, the alignment and assembly of the light-harvesting protein machinery in the green leaf optimize the ability to efficiently convert light from the sun to form chemical bonds. In artificial systems, strategies based on self-assembly using noncovalent interactions offer the possibility to mimic this functional correlation among molecules to optimize photocatalysis, photovoltaics, and energy storage. One of the long-term objectives of the field described here as supramolecular energy materials is to learn how to design soft materials containing light-harvesting assemblies and catalysts to generate fuels and useful chemicals. Supramolecular energy materials also hold great potential in the design of systems for photovoltaics in which intermolecular interactions in self-assembled structures, for example, in electron donor and acceptor phases, maximize charge transport and avoid exciton recombination. Possible pathways to integrate organic and inorganic structures by templating strategies and electrodeposition to create materials relevant to energy challenges including photoconductors and supercapacitors are also described. The final topic discussed is the synthesis of hybrid perovskites in which organic molecules are used to modify both structure and functions, which may include chemical stability, photovoltaics, and light emission.     

Modulation of Bi2MoO6‐Based Materials for Photocatalytic Water Splitting and Environmental Application: a Critical Review

Highly active photocatalysts driving chemical reactions are of paramount importance toward renewable energy substitutes and environmental protection. As a fascinating Aurivillius phase material, Bi₂MoO₆ has been the hotspot in photocatalytic applications due to its visible light absorption, nontoxicity, low cost, and high chemical durability. However, pure Bi₂MoO₆ suffers from low efficiency in separating photogenerated carriers, small surface area, and poor quantum yield, resulting in low photocatalytic activity. Various strategies, such as morphology control, doping/defect‐introduction, metal deposition, semiconductor combination, and surface modification with conjugative π structures, have been systematically explored to improve the photocatalytic activity of Bi₂MoO₆. To accelerate further developments of Bi₂MoO₆ in the field of photocatalysis, this comprehensive Review endeavors to summarize recent research progress for the construction of highly efficient Bi₂MoO₆‐based photocatalysts. Furthermore, benefiting from the enhanced photocatalytic activity of Bi₂MoO₆‐based materials, various photocatalytic applications including water splitting, pollutant removal, and disinfection of bacteria, were introduced and critically reviewed. Finally, the current challenges and prospects of Bi₂MoO₆ are pointed out. This comprehensive Review is expected to consolidate the existing fundamental theories of photocatalysis and pave a novel avenue to rationally design highly efficient Bi₂MoO₆‐based photocatalysts for environmental pollution control and green energy development.     

Biotemplated preparation of CdS nanoparticles/bacterial cellulose hybrid nanofibers for photocatalysis application

In this work, we describe a novel facile and effective strategy to prepare micrometer-long hybrid nanofibers by deposition of CdS nanoparticles onto the substrate of hydrated bacterial cellulose nanofibers (BCF). Hexagonal phase CdS nanocrystals were achieved via a simple hydrothermal reaction between CdCl(2) and thiourea at relatively low temperature. The prepared pristine BCF and the CdS/BCF hybrid nanofibers were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV-vis absorption spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results reveal that the CdS nanoparticles were homogeneously deposited on the BCF surface and stabilized via coordination effect. The CdS/BCF hybrid nanofibers demonstrated high-efficiency photocatalysis with 82% methyl orange (MO) degradation after 90 min irradiation and good recyclability. The results indicate that the CdS/BCF hybrid nanofibers are promising candidate as robust visible light responsive photocatalysts.     

Preparation and characterization of ZnO-TiO2 nanocomposite for photocatalytic disinfection of bacteria and detoxification of cyanide under visible light

ZnO-TiO₂ nanocomposite was prepared by modified ammonia-evaporation-induced synthetic method. It was characterized by powder X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and energy dispersive X-ray, UV-visible diffuse reflectance, photoluminescence and electrochemical impedance spectroscopies. Incorporation of ZnO leads to visible light absorption, larger charge transfer resistance and lower capacitance. The nanocomposite effectively catalyzes the inactivation of E. coli under visible light. Further, the prepared nanocomposite displays selective photocatalysis. While its photocatalytic efficiency to detoxify cyanide with visible light is higher than that of TiO₂ P25, its efficiency to degrade methylene blue, sunset yellow and rhodamine B dyes under UV-A light is less than that of TiO₂ P25.     

Accelerating Photogenerated Charge Kinetics via the Synergetic Utilization of 2D Semiconducting Structural Advantages and Noble‐Metal‐Free Schottky Junction Effect

Although photocatalysis is one of the most promising technologies for environmental and energy issues, the irreconcilable contradiction between the absorption of the visible light and the strong redox capability of the photocatalyst and the low photocatalytic reaction kinetics result in the poor efficiency. Here, a composite photocatalyst is reported with high redox capability and accelerated reaction kinetics synergistically utilizing 2D semiconducting structural advantages and the noble‐metal‐free Schottky junction effect. The 2D structure can not only increase the bandgap of the photocatalyst but also improve the transfer and separation of the photogenerated charge carriers. Furthermore, the introduction of the noble‐metal‐free Schottky junction effect accelerates the photocatalytic reaction kinetics. The Schottky barrier can also prevent the photogenerated charges trapped by the electron acceptor from flowing back to the semiconductor, which can further boost the photocatalytic performance. The transfer process of the photogenerated charge carriers is also researched in detail by the comprehensive characterization methods, which enable the photocatalytic mechanism to be revealed.     

A review:Synthesis,modification and photocatalytic applications of ZnIn2S4

Solar energy is an ideal energy source for solving energy shortages and serious environmental problems.In the past few decades,photocatalytic technology which uses solar energy to deal with the above prob-lems has caused great interest.ZnIn2S4,as a layered ternary metal chalcogenide compound,has a series of advantages such as the wide light absorption range and adjustable bandgap.It has been applied in the different fields of photocatalysis in recent years.This review introduced the crystal structures and growth mechanism of ZnIn2S4 and summarized the preparation methods of ZnIn2S4.Also,the promoted strate-gies of ZnIn2S4 based photocatalytic system and their applications in the pollutant removal,hydrogen evolution,reduction of CO2,nitrogen fixation,and chemical synthesis was summarized.Furthermore,the challenges and development directions of the current ZnIn2S4 based photocatalytic system were proposed.It is hoped that this review will help researchers design a better ZnIn2S4 based photocatalytic system.     

TiO2-based photocatalysts prepared by oxidation of TiN nanoparticles and their photocatalytic activities under visible light illumination

To develop TiO₂-based photocatalysts with visible light activity for better solar energy utilization, a simple flash oxidation method was developed by calcining commercial TiN nanoparticle to prepare N-doped TiO₂ photocatalyst and TiN/TiO₂ composite photocatalysts through the modulation of the calcination time and temperature. It was found that more energy and processing time were needed to prepare N-doped TiO₂ photocatalyst than that of TiN/TiO₂ composite photocatalyst during this process, while TiN/TiO₂ composite photocatalyst had a better visible light absorption/photocatalytic performance than that of N-doped TiO₂ photocatalyst prepared from the oxidation of the same TiN precursor. Thus, the preparation of TiN/TiO₂ composite photocatalyst from TiN precursor should be a more preferred approach than the preparation of N-doped TiO₂ photocatalyst for visible-light-activated photocatalysis for its cost-effectiveness.