Solar‐energy‐driven CO2 conversion into value‐added chemical fuels holds great potential in renewable energy generation. However, the rapid recombination of charge carriers and deficient reactive sites, as two major obstacles, severely hampers the photocatalytic CO2 reduction activity. Herein, a desirable surface halogenation strategy to address the aforementioned concerns over a Sillén‐related layer‐structured photocatalyst Bi2O2(OH)(NO3) (BON) is demonstrated. The surface halogen ions that are anchored on the Bi atoms by replacing surface hydroxyls on the one hand facilitate the local charge separation, and, on the other hand, activate the hydroxyls that profoundly boost the adsorption of CO2 molecules and protons and facilitate the CO2 conversion process, as evidenced by experimental and theoretical results collectively. Among the three series of BON‐X (X = Cl, Br, and I) catalysts, BON‐Br shows the most substantially enhanced CO production rate (8.12 µmol g?1 h?1) without any sacrificial agents or cocatalysts, ≈73 times higher than that of pristine Bi2O2(OH)(NO3), also exceeding that of the state‐of‐the‐art photocatalysts reported to date. This work presents a surface polarization protocol for engineering charge behavior and reactive sites to promote photocatalysis, which shows great promise to the future design of high‐performance materials for clean energy production. 相似文献
Ferroelectric materials with spontaneous polarization-induced internal electric fields have drawn increasing attention in solar fuel production due to the intrinsic polarized structure. However, the origination of charge separation in these materials at the nano/microlevel is ambiguous owing to the complexity of the multielectric fields. Besides, the observed charge separation ability is far from theoretical expectation. Herein, by spatially resolved surface photovoltage spectroscopy, it is clearly demonstrated that the depolarization field in single-domain ferroelectric PbTiO3 (PTO) nanoplates is the main driving force for charge separation and it can effectively drive photogenerated electrons and holes to the positive and negative polarization facets, respectively. Moreover, the charge separation ability of PTO nanoplates increases with increasing particle size along the polarization direction, due to the increasing potential difference between the opposite polarization facets. Furthermore, this driving force for charge separation directly contributes to the enhancement of the photocatalytic hydrogen evolution reaction activity in ferroelectrics. Finally, it is proved that the screening field compensates part of the depolarization field and can be diminished by adding a dielectric layer on the ferroelectric surface. These findings demonstrate the importance of increasing the depolarization field and decreasing the screening field for efficient charge separation in ferroelectric semiconductor photocatalysts. 相似文献
Hollow nanoreactors (HoNRs) have regarded as an attractive catalytic material for photocatalysis due to their exceptional capabilities in enhancing light harvesting, facilitating charge separation and transfer, and optimizing surface reactions. Developing novel HoNRs offers new options to realize controllable catalytic behavior. However, the catalytic mechanism of photocatalysis occurring in HoNRs has not yet been fully revealed. Against this backdrop, this review elaborates on three aspects: 1) the fundamental theoretical insights of HoNRs-driven photocatalytic kinetics; 2) structure–performance relationship of HoNRs to photocatalysis; 3) catalytic advantages of HoNRs in photocatalytic applications. Specifically, the review focuses on the fundamental theories of HoNRs for photocatalysis and their structural advantages for strengthening light scattering, promoting charge separation and transfer, and facilitating surface reaction kinetics, and the relationship between key structural parameters of HoNRs and their photocatalytic performance is in-depth discussed. Also, future prospects and challenges are proposed. It is anticipated that this review paper will pave the way for forthcoming investigations in the realm of HoNRs for photocatalysis. 相似文献
Prompt recombination of photogenerated electrons and holes in bulk and on the surface of photocatalysts harshly impedes the photocatalytic efficiency. However, the simultaneous manipulation of photocharges in the two locations is challenging. Herein, the synchronous promotion of bulk and surface separation of photoinduced charges for prominent CO2 photoreduction by coupling macroscopic spontaneous polarization and surface oxygen vacancies (OVs) of BiOIO3 single crystals is reported. The oriented growth of BiOIO3 single-crystal nanostrips along the [001] direction, ensuing substantial well-aligned IO3 polar units, renders a large enhancement for the macroscopic polarization electric field, which is capable of driving the rapid separation and migration of charges from bulk to surface. Meanwhile the introduction of surface OVs establishes a local electric field for charge migration to catalytic sites on the surface of BiOIO3 nanostrips. Highly polarized BiOIO3 nanostrips with ample OVs demonstrate outstanding CO2 reduction activity for CO production with a rate of 17.33 µmol g−1 h−1 (approximately ten times enhancement) without any sacrificial agents or cocatalysts, being one of the best CO2 reduction photocatalysts in the gas–solid system reported so far. This work provides an integrated solution to governing charge movement behavior on the basis of collaborative polarization from bulk and surface. 相似文献
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. 相似文献
As an effort to develop a simple and versatile synthetic strategy that contributes to the evolution of hollow nanostructures with increasing complexity and functionality, this research is devoted to study the hollow transformation within a nanosized solid matrix. Through an in‐depth investigation of a hollowing process of MnO nanocrystals confined within a Ni2+ incorporating silica nanosphere, a very distinct transformation pathway can be explained that produces the yolk@shell nanostructure with a single Ni nanocrystal inside a silicate nanoshell. The yolk@shell structure is developed by a mechanism combining different processes, including the formation of a (Ni0.1Mn0.9)O mixed‐metal oxide and subsequent segregation of the reduced Ni. Furthermore, this study also devises a protocol to exploit the solid‐state‐synthesized powder for fabricating a colloidal hollow nanoreactor that can selectively catalyze the reduction of nitroarenes and be recycled via the magnetic process. 相似文献
Currently, blade-coated perovskite solar cells (PSCs) with high power conversion efficiencies (PCEs), that is, greater than 20%, normally employ methylammonium lead tri-iodide with a sub-optimal bandgap. Alloyed perovskites with formamidinium (FA) cation have narrower bandgap and thus enhance device photocurrent. However, FA-alloyed perovskites show low phase stability and high moisture sensitivity. Here, it is reported that incorporating 0.83 molar percent organic halide salts (OHs) into perovskite inks enables phase-pure, highly crystalline FA-alloyed perovskites with extraordinary optoelectronic properties. The OH molecules modulate the crystal growth, enhance the phase stability, passivate ionic defects at the surface and/or grain boundaries, and enhance the moisture stability of the perovskite film. A high efficiency of 22.0% under 1 sun illumination for blade-coated PSCs is demonstrated with an open-circuit voltage of 1.18 V, corresponding to a very small voltage deficit of 0.33 V, and significantly improved operational stability with 96% of the initial efficiency retained under one sun illumination for 500 h. 相似文献
Hollow microspheres of two bismuth oxychlorides, BiOCl and Bi24O31Cl10, were successfully synthesized using carbonaceous microsphere sacrificial templates. The phase evolution from BiOCl to Bi24O31Cl10 was easily realized by heating the former at 600 °C. With a uniform diameter of about 200 nm, an average shell thickness of 40 nm, and basic nanosheets of <20 nm, the hollow microspheres of both BiOCl and Bi24O31Cl10 showed high visible light photocatalytic activity towards the degradation of Rhodamine B (RhB). Besides the effective photosensitization process and efficient photointroduced carrier separation, the high photocatalytic activity was believed to result from their hollow-structure-dependent large visible light absorption. Moreover, as a chlorine-deficient analogue, the Bi24O31Cl10 hollow spheres possessed a narrower band gap, more dispersive band structure, and higher photocarrier conversion efficiency, which further helped them to exhibit better photocatalytic activity.
Lanthanide‐doped nanomaterials have attracted significant attention for their preeminent properties and widespread applications. Due to the unique characteristic, the lanthanide‐doped photoluminescence materials with hollow structures may provide advantages including enhanced light harvesting, intensified electric field density, improved luminescent property, and larger drug loading capacity. Herein, the synthesis, properties, and applications of lanthanide‐doped photoluminescence hollow structures (LPHSs) are comprehensively reviewed. First, different strategies for the engineered synthesis of LPHSs are described in detail, which contain hard, soft, self‐templating methods and other techniques. Thereafter, the relationship between their structure features and photoluminescence properties is discussed. Then, niche applications including biomedicines, bioimaging, therapy, and energy storage/conversion are focused on and superiorities of LPHSs for these applications are particularly highlighted. Finally, keen insights into the challenges and personal prospects for the future development of the LPHSs are provided. 相似文献
This paper describes a facile method of preparing cubic Au nanoframes with open structures via the galvanic replacement reaction
between Ag nanocubes and AuCl2−. A mechanistic study of the reaction revealed that the formation of Au nanoframes relies on the diffusion of both Au and
Ag atoms. The effect of the edge length and ridge thickness of the nanoframes on the localized surface plasmon resonance peak
was explored by a combination of discrete dipole approximation calculations and single nanoparticle spectroscopy. With their
hollow and open structures, the Au nanoframes represent a novel class of substrates for applications including surface plasmonics
and surface-enhanced Raman scattering.
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Recent years have witnessed an incredibly high fever in metal halide perovskite materials due to their promising applications in a wide range of optoelectronic applications. The morphologies and optoelectronic properties of the perovskite layers play critical roles in affecting the optoelectronic performances. This review summarizes the recent advances in the fabrication of a variety of perovskite morphologies and their promising progress achieved in different optoelectronic applications, including solar cells, light‐emitting diodes, photodetectors, lasers, photocatalysis, X‐ray detectors/imagers, and luminescent solar concentrators. Several blossoming representatives, including 0D perovskite quantum dots, 1D perovskite nanowires, 2D perovskite nanosheets/nanoplatelets, and 3D textured perovskite assemblies (i.e., cuboid‐like, inverse opal‐like, coral‐like, or maze‐like morphologies, etc.), are highlighted to demonstrate their fascinating properties and outstanding capabilities for efficient optoelectronic applications. Finally, a perspective on the remaining challenges and future directions of fabricating unique perovskite morphologies for next‐generation high‐performance optoelectronic devices is provided. 相似文献
Engineered heterostructures create new functionality by integrating dissimilar materials. Combining different 2D crystals naturally produces two distinct classes of heterostructures, vertical van der Waals (vdW) stacks or 2D sheets bonded laterally by covalent line interfaces. When joining thicker layered crystals, the arising structural and topological conflicts can result in more complex geometries. Phase separation during one‐pot synthesis of layered tin chalcogenides spontaneously creates core–shell structures in which large orthorhombic SnS crystals are enclosed in a wrap‐around shell of trigonal SnS2, forcing the coexistence of parallel vdW layering along with unconventional, orthogonally layered core–shell interfaces. Measurements of the optoelectronic properties establish anisotropic carrier separation near type II core–shell interfaces and extended long‐wavelength light harvesting via spatially indirect interfacial absorption, making multifunctional layered core–shell structures attractive for energy‐conversion applications. 相似文献
Ultraviolet (UV) light can be used in versatile applications ranging from photoelectronic devices to biomedical imaging. In the development of new UV light sources, in this study, stable UV emission at ≈350 nm is unprecedentedly obtained from carbon nanospheres (CNSs). The origin of the UV fluorescence is comprehensively investigated via various characterization methods, including Raman and Fourier transform infrared analyses, with comparison to the visible emission of carbon nanodots. Based on the density functional calculations, the UV fluorescence is assigned to the carbon nanostructures bonded to bridging O atoms and dangling –OH groups. Moreover, a twofold enhancement in the UV emission is acquired for Au‐carbon core‐shell nanospheres (Au‐CNSs). This remarkable modification of the UV emission is primarily ascribed to charge transfer between the CNSs and the Au surface. 相似文献
Introducing heterojunction is an effective way for improving the intrinsic photocatalytic activity of a graphitic carbon nitride (GCN) semiconductor. These heterostructures are mostly introduced by interfacing GCN with foreign materials that normally have entirely different physicochemical properties and show unfavorable compatibility, thus resulting in a limited improvement of the photocatalytic performance of the resultant materials. Herein, a composite polymeric carbon nitride (CPCN) that contains both melon‐based GCN and triazine‐based crystalline carbon nitride (CCN) is prepared by a simple thermal reaction between lithium chloride and GCN. Thanks to the intimate contact and good compatibility between GCN and CCN, an in situ formed heterojunction acts as a driving force for separating the photogenerated charge carriers in CPCN. As a result, CPCN exhibits a significantly improved photocatalytic performance under visible light irradiation, which is, respectively, 10.6 and 5.3 times as high as those of the GCN and CCN alone. This well designed isotype heterojunction by a coupling of CCN presents an effective avenue for developing efficient GCN photocatalysts. 相似文献
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