Providing novel photocatalysts with high photocatalytic efficiency is of great significance. In the present work, hydrogen peroxide and carbon dots (C-Dots) were utilized to enhance the photocatalytic performance of TiO2 under visible light. The fabricated TiO2-peroxo/C-Dots photocatalysts were analyzed by XRD, HRTEM, SEM, EDX, BET, FT-IR, XPS, PL, UV–Vis DRS, EIS, and photocurrent density. Photocatalytic abilities of the nanocomposites were evaluated by photocatalytic removal of RhB, MO, MB, fuchsine, and Cr (VI) upon visible-light illumination. The results demonstrated that the binary nanocomposites exhibited remarkably enhanced photocatalytic activity compared with the TiO2 and TiO2-peroxo photocatalysts. The best photocatalytic performance was obtained using 0.75?mL of C-Dots, which was approximately 79.2, 17.1, 71.4, and 40.5 times higher than the pure TiO2 for degradations of RhB, MO, MB, and fuchsine, respectively. Furthermore, the TiO2-peroxo/C-Dots nanocomposites exhibited high stability in consecutive photocatalytic processes. Based on the results, the TiO2-peroxo/C-Dots photocatalyst is expected to become a promising photocatalyst for practical applications in water purification. 相似文献
Graphene is a novel two-dimensional nanomaterial that holds great potential in electronic and sensor applications. By etching the edges to form nanoribbons or introducing defects on the basal plane, it has been demonstrated that the physical and chemical properties of graphene can be drastically altered. However, the lithographic or chemical techniques required to reliably produce such nanoribbons remain challenging. Here, we report the fabrication of nanosensors based on holey reduced graphene oxide (hRGO), which can be visualized as interconnected graphene nanoribbons. In our method, enzymatic oxidation generated holes within the basal plane of graphene oxide, and after reduction with hydrazine, hRGO was formed. When decorated with Pt nanoparticles, hRGO exhibited a large and selective electronic response toward hydrogen gas. By combining experimental results and theoretical modeling, we propose that the increased edge-to-plane ratio, oxygen moieties, and Pt nanoparticle decoration were responsible for the observed gas sensing with hRGO nanostructures. 相似文献
The depletion of energy and increasing environmental pressure have become one of the main challenges in the world today. Synthetic high-efficiency catalysts bring hope for efficient conversion of energy and effective treatment of pollutants, especially, single-atom catalysts (SACs) are promising candidates. Herein, we comprehensively summarizes the atomic diffusion strategy, which is considered as an effective method to prepare a series of SACs. According to the different diffusion forms of the precursors, we review the synthesis pathways of SACs from three aspects: gas diffusion, solid diffusion and liquid diffusion. The gaseous diffusion method mainly discusses atomic layer deposition (ALD) and chemical vapor deposition (CVD), both of which carry out gas phase mass transfer at high temperatures. The solid-state diffusion method can be divided into nanoparticle transformation into single atoms and solid atom migration. Liquid diffusion mainly describes the electrochemical method and the molten salt method. We hope this review can trigger the rational design of SACs.
Open-cell stainless steel foams, composed of hollow struts, are excellent candidates for energy absorption and thermo-mechanical applications. The basic mechanical element responsible for the function of these foams is the single strut. However, testing and characterisation of single foam struts to predict the foam strength have stirred up a new debate about approaches to micro-tensile testing of such elements. In this paper, we present a protocol for in-situ micro-tensile testing of hollow steel struts using a custom-made grip system. The adapted grips make it possible to perform analysis of the deformation of multiple sintered struts. Here we present and discuss challenges encountered during such micro-tensile testing of hollow steel struts. 相似文献
DNA is the prototype template for building nanoelectronic devices by self-assembly. The electronic functions are made possible by coordinating electronic polymer chains to DNA. This paper demonstrates two methods for fabrication of aligned and ordered DNA nanowires complexed with conjugated polyelectrolytes (CPEs). The complex can be formed either in solution prior to stretching or after stretching of the bare DNA on a surface. Molecular combing was used to stretch the complexes on surface energy patterned surfaces, and PMMA for the bare DNA. Single molecular spectroscopy, in fluorescence, and microscopy, in atomic force microscopy, give evidence for coordination of the short CPE chains to the aligned DNA. 相似文献
The role of Coulomb correlations on the resonant charge transfer in atom scattering on an atom adsorbed on a metal surface has been studied theoretically within the Hartree-Fock approximation and the time-dependent Anderson-Newns model. Using the evolution operator technique the probabilities of the different charge states of the back-scattered atoms were calculated for broad range of parameters. In particular, the effect of the constant or z-dependent (z being the distance of the moving atom from the surface) effective intra-atomic Coulomb correlations was analysed. 相似文献
Due to its appropriate bandgap(~2.4 eV)and efficient light absorption,bismuth vanadate(BiVO4)shows promising photocatalysis activity.However,the charge carrier recombination and poorelectron transmis-sion often induce poor photocatalytic performance.Herein,we report a new method to in-situ synthesize non-noble metal Bi decorated mulberry-like BiVO4 by a two-step calcination process.Comprehensive characterizations reveal that non-noble metal Bi nanoparticles grown in-situ on BiVO4 result in the red-shift of the absorbance edge,greatly extending the light absorption from the ultraviolet into the near-infrared region.The surface plasmon resonance excitation of Bi nanoparticles and synergetic effects between Bi and BiVO4 effectively improve the photocatalytic efficiency and promote the separation of photoinduced electron-hole pairs in mulberry-like BiVO4.Density functional theory(DFT)calculation results further verify that the electrons are transferred from Bi to BiVO4 and the formation of·OH radical in Bi/BiVO4 is attributed to the lower simulated free energy,which supports our experimental outcomes.This work provides a novel strategy to enhance light absorption and promote efficient solar utilization of photocatalysts for practical applications. 相似文献
Benefiting from strong redox ability,improved charge transport,and enhanced charge separation,Z-scheme heterostructures of ZnIn2S4 based photocatalysts have received considerable interest to tackle energy needs and environmental issues.The present review highlights the properties of ZnIn2S4 which make it a promising photocatalyst,and a suitable combination with oxidation photocatalyst to form Z-scheme,leading to improve their photocatalytic properties dramatically.As the central part of this review,various types of Z-scheme heterojunction developed recently based on ZnIn2S4 and their application in pollutant degradation,water splitting,CO2 reduction,and toxic metals remediation.Some analytical techniques to detect or trap the active radical and study the charge separation and lifetime of charge carriers in these Z-schemes are highlighted.This review offers its readers a broad optical window for the structural architecture of ZnIn2S4-based Z-schemes,photocatalytic activity,stability,and their tech-nological applications.Finally,we discuss the challenges and opportunities for further development on Z-Scheme ZnIn2S4-based photocatalysts toward energy and environmental applications based on the recent progress. 相似文献
This work is a review of recent progress on spectroscopic measurements in hydrogen, in the optical domain and in the microwave domain. It is shown that having knowledge of the Rydberg constant at the level of 10-11 will furnish in the future a new relation between microwave and optical frequencies 相似文献
Development of metal matrix composites has extended the choice of materials particularly for the space, aero-space and automobile
industries, with a view to reduce fuel consumption and operating cost by weight saving. Tailoring of a composite to suit a
given application requires choice of constituents and promotion of desirable interfaces. Solidifcation processing of composites
demands particular attention to wetting of dispersoids by alloys, defects like porosities and evolution of microstructures
particularly in respect of changing the nature of interfaces in a composite. 相似文献
The efficient conversion of solar energy to electricity for human utilization heavily relies on the development of solar cells. Nowadays, a variety of high-performance solar cells are constantly emerging. Thin-film solar cells made from inorganic materials have constituted one of the major categories of solar cells showing potential in the fast growing photovoltaic (PV) market. In order to provide an overall grasp of and insight into the future direction of inorganic thin-film solar cell development, we review key emerging and representative inorganic photovoltaic materials including chalcopyrite Cu(In,Ga)Se2 (CIGSe), kesterite Cu2ZnSn(S,Se)4 (CZTSSe), CdTe, Sb2Se3 and inorganic perovskite CsPb(I1−xBrx)3 in this paper. Absorber materials, evolution of device development, and current challenges and key strategies for performance enhancement are detailed. 相似文献
Multijunction solar cells are the most efficient solar cells ever developed with demonstrated efficiencies above 40%, far in excess of the performance of any conventional single-junction cell. This paper describes paths toward next-generation multijunction cells with even higher performance. Starting from fundamental multijunction concepts, the paper describes the desired characteristics of semiconductor materials for multijunction cells; the corresponding challenges in obtaining these characteristics in actual materials; and materials and device architectures to overcome these challenges. 相似文献
This paper describes the thermal oxidative behavior of atomized iron or atomized cobalt in the presence of multiwalled carbon nanotubes (MWCNT). The thermogravimetric analysis shows the atomized iron thermal oxidation starts at about 500 degrees C that is absent when the atomized iron is sintered with multiwalled carbon naonotubes. The thermal oxidation of iron in the sintered samples requires the collapse of the multiwalled carbon nanotubes. A similar behavior is observed with atomized cobalt when its oxidation requires the collapse of the nanotubes. This thermal oxidative shift is interpreted as due to the atomized iron or atomized cobalt atom experiencing extensive overlap and confinement effect with multiwalled carbon nanotubes causing a spin transfer. This confinement effect is suggested to produce a transformation of iron from the outermost electronic distribution of 3d64s2 to an effective configuration of 3d84s0 and for cobalt 3d74s2 to 3d94s0 producing spintronics effect. 相似文献
Nanoparticle fluid suspensions were prepared using photochemically functionalized multiwalled carbon nanotubes in polar base fluids. Multiwalled carbon nanotubes prepared by catalytic chemical vapour deposition technique have been functionalized by irradiating with ultraviolet light of wavelength 254 nm. The photochemical oxidation of multiwalled carbon nanotubes under UV irradiation introduces oxygen containing functional groups onto the surface of the nanotubes, generating new defects on their structure. Silver nanoparticles have been deposited over multiwalled carbon nanotubes by chemical method. The enhancement in thermal conductivity of the prepared nanofluids using functionalized multiwalled carbon nanotubes and Ag nanoparticles deposited functionalized multiwalled carbon nanotubes with volume fraction, temperature and aspect ratio has been demonstrated. Silver deposited functionalized multiwalled carbon nanotubes based nanofluids in DI water with 0.02% volume fraction exhibit a thermal conductivity enhancement of 9.9% and 47% at room temperature and at 50 degrees C respectively. 相似文献
Non-lithium ion (Na/K/Mg/Ca/Zn/Al-ion) batteries (NLIBs) have stepped into the spotlight as alternatives or supplements to lithium-ion batteries in large-scale energy storage systems with the aid of vast advantages in resource and production cost. In the past years, a lot of efforts have been taken to develop high-performance cathode materials for various NLIBs by exploiting new cathode materials or optimizing the existing categories. As an efficient optimizing strategy to break the bottleneck of intrinsic lattice, crystal defect modulation attracts much attention and has been applied in many cathode materials. Suitable crystal defects in cathode materials could enhance the electrochemical reactivity, electronic conductivity, ionic diffusivity, and structural stability, then improving the capacity, rate performance and cycling stability of batteries. In this review, the investigations of crystal defect modulation in cathode materials for NLIBs are systematically summarized by highlighting some typical and recent progresses. The positive effects and improvement mechanism of intentionally introduced defects, including substitutional impurity, interstitial impurity, vacancy defect, cation disorder and amorphization, are discussed. Besides, the challenges and the perspectives about future directions of crystal defect modulation on the cathode materials for NLIBs are presented. 相似文献
Polymer nanocomposites based on thermoplastic polyurethane (PU) elastomer and metal nanoparticle (Ag and Cu) decorated multiwall carbon nanotubes (M-CNTs) were prepared through melt mixing process and investigated for its mechanical, dynamic mechanical and electro active shape memory properties. Structural characterization and morphological characterization of the PU nanocomposites were done using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Morphological characterization revealed better dispersion of M-CNTs in the polyurethane, which is attributed to the improved interaction between the M-CNTs and polyurethane. Loading of the metal nanoparticle coated carbon nanotubes resulted in the significant improvement on the mechanical properties such as tensile strength of the PU composites in comparison to the pristine carbon nanotubes (P-CNTs). Dynamic mechanical analysis showed that the glass transition temperature (Tg) of the polyurethane increases slightly with increasing loading of both pristine and metal nanoparticle functionalized carbon nanotubes. The metal nanoparticles decorated carbon nanotubes also showed significant improvement in the thermal and electrical conductivity of the PU/M-CNTs nanocomposites. Shape memory studies of the PU/M-CNTs nanocomposites exhibit remarkable recoverability of its shape at lower applied dc voltages. 相似文献