Display omitted
•Bi2S3-BiOBr nanosheets were synthesized on TiO2 NTA/Ti mesh.•The Bi2S3-BiOBr/TiO2 NTAs showed the attractive hydrogen generation activity.•The active species and photocatalytic ...mechanism were studied.
Novel energy material is the investigation focus to overcome the environment pollution and resource shortage crisis. TiO2 nanotube arrays (TiO2 NTA) could be used for pollutant decomposition, photoelectric conversion and H2, CH4 generation. BiOBr nanosheets were fabricated on TiO2 NTA by a solvothermal deposition method, and then transformed into Bi2S3 nanosheets after the ion exchange reaction. The results revealed that the ion concentration significantly influenced the morphology, microstructure, optical harvesting and photoelectrochemical capacity of Bi2S3-BiOBr/TiO2 NTA. The samples also exhibited high photocatalytic activity for the removal of dyes and Cr(VI), and the excellent photocurrent and photovoltage were obtained under visible light irradiation. The photocatalytic water splitting for hydrogen generation was carried out, and the photocatalytic hydrogen production rate achieved 17.26 μmol·cm−2·h−1. The photocatalyst showed the remarkable stability, and the photocatalytic ability still maintained high level after several repeated photocatalytic cycles. The photocatalytic data indicated that the Bi2S3-BiOBr/TiO2 NTA photocatalyst provided a perfect strategy for the sensitizer deposition on TiO2 NTA and novel approach for the photocatalytic performance improvement.
. It is speculated that the Sb2O3 nanorod-bundles are formed mainly via a three-step sequence, i.e. nucleation, self-assembly and 1D oriented attachment growth. The nucleated grains first grow into ...small nanoparticles, and were absorbed by PVA molecules. After this, PVA self-assembled into micelles with the layered structures and these Sb2O3 nanoparticles aggregated into microdisks of ∼230nm in diameter. Furthermore, the remaining seeds attached on the surface of the microdisks and grew into short rods. The arms were elongated by oriented attachment on the end of each rod, which led to the formation of a long rod. Finally, product with bundle-like structures is obtained with the growth of arms along the 001 direction. The whole formation of Sb2O3 nanorod-bundles can be summarized in the schematic illustration as shown in the figure. Display omitted
► We report the fabrication of uniform Sb2O3 nanorod-bundles via a facile hydrothermal synthetic method. ► Morphology, composition, microstructure and optical property of Sb2O3 nanorod-bundles were researched. ► The self-assembly assisted oriented attachment mechanism was proposed.
Sb2O3 nanorod-bundles with length of about 4μm were fabricated in the presence of polyvinyl alcohol (PVA) by a simple hydrothermal method. The composition, morphology, microstructure and optical property of the as-prepared bundles were characterized by XRD, XPS, SEM, TEM and Raman spectrum. The results showed that the nanorod-bundles were composed of massive orthorhombic phase Sb2O3 nanorods grown along 001 direction. It was speculated that the nanorod-bundles developed through self-assembly of initially scattered nuclei into microdisks and subsequent oriented attachment process. PVA played a crucial role in the formation of Sb2O3 nanorod-bundles.
Bi2WO6 particles with controlled morphologies of nanosheets, microroses and microspheres were obtained by the solvothermal Sb3+ doping, and the Bi2WO6 deposition on TiO2 nanotubes with different Sb3+ ...doping amounts influenced the solar absorption, photocurrent and photocatalytic ability. The rose-like BWO-10 photoelectrode showed more excellent photocurrent (0.24 mA/cm2), outstanding photovoltage (−0.24 V) and interface resistance than those of other samples under visible light irradiation. The BWO-10 photoelectrode also exhibited excellent photocatalytic activity, and 80.58%, 77.23%, 99.06% and 93.84% of rhodamine B (RhB), methyl orange (MO), methylene blue (MB) dye molecules and Cr (VI) ions could be removed. The active species and photocatalytic mechanism for the pollutant treatment were explored based on the free radical capture experiments. The optimization of morphology and energy band structure was the main reason for the dramatical improvement of photocatalytic performances. The work illustrates the advance of metal ion doping in semiconductor photocatalysts, which provides the effective strategy for the preparation of photocatalysts with high photocatalytic performances in wastewater purification.
Display omitted
•The rose-like Sb3+ doped Bi2WO6 was prepared on TiO2 NTAs by solvothermal methods.•The dopant concentration had vital influences on the morphology, optical absorption and photoelectrochemical activity.•The Sb3+ doped Bi2WO6/TiO2 NTAs showed outstanding photoelectric conversion and photocatalytic performances.
Display omitted
•The CdS/Bi/TiO2 NTs photocatalyst with remarkable photocatalytic performance was prepared.•The CdS/Bi/TiO2 NTs exhibited fascinating ability of photocatalytic wastewater ...treatment.•CdS/Bi/TiO2 NTs photoelectrodes displayed the attractive photocatalytic H2 production.•Possible carrier transfer mechanisms were discussed, and S-scheme heterojunction is proposed.
A composite Bi/CdS/TiO2 nanotube arrays (TiO2 NTs) photocatalyst with remarkable photocatalytic performance was prepared by the successive ionic layer adsorption and reaction (SILAR) method. The crystallinity of the samples was determined by XRD and TEM, and the SEM results showed the successful formation of Bi and CdS. The excellent photocatalytic performance of CdS/Bi/TiO2 NTs was confirmed by the degradation of rhodamine B (RhB), methylene blue (MB) and the reduction of Cr(VI), specifically, the removal efficiency reached 100 % toward MB degradation after 2 h irradiation, 85.41% and 97.04% for RhB and Cr(VI) after 3 h irradiation. In addition, CdS/Bi/TiO2 NTs exhibited stable electrochemical properties. The S-scheme heterostructure photocatalytic mechanism was proposed based on the energy band structure calculation and radical formation analysis from electron spin resonance (ESR). The hydrogen production rate of CdS/Bi/TiO2 NTs reached 673.81 μmol·h−1·cm−2, and the high stability of CdS/Bi/TiO2 NTs was exhibited in the cycling test of hydrogen production and dye degradation, confirming the stability improvement role of Bi nanoparticles.
A simple one-step calcination route was used to prepare Ti3+ self-doped TiO2/g-C3N4 heterojunctions by mixture of H2Ti3O7 and melamine. X-ray diffraction (XRD), transmission electron microscopy ...(TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) spectroscopy, and UV–Vis diffuse reflectance spectroscopy (UV–vis DRS) technologies were used to characterize the structure, crystallinity, morphology, and chemical state of the as-prepared samples. The absorption of the prepared Ti3+ self-doped TiO2/g-C3N4 heterojunctions shifted to a longer wavelength region in comparison with pristine TiO2 and g-C3N4. The photocatalytic activities of the heterojunctions were studied by degrading methylene blue under a 30 W visible-light-emitting diode irradiation source. The visible-light photocatalytic activities enhanced by the prepared Ti3+ self-doped TiO2/g-C3N4 heterojunctions were observed and proved to be better than that of pure TiO2 and g-C3N4. The photocatalysis mechanism was investigated and discussed. The intensive separation efficiency of photogenerated electron–hole in the prepared heterojunction was confirmed by photoluminescence (PL) spectra. The removal rate constant reached 0.038 min–1 for the 22.3 wt % Ti3+ self-doped TiO2/g-C3N4 heterojunction, which was 26.76 and 7.6 times higher than that of pure TiO2 and g-C3N4, respectively. The established heterojunction between the interfaces of TiO2 nanoparticles and g-C3N4 nanosheets as well as introduced Ti3+ led to the rapid electron transfer rate and improved photoinduced electron–hole pair’s separation efficiency, resulting in the improved photocatalytic performance of the Ti3+ self-doped TiO2/g-C3N4 heterojunctions.
Images in figure show the low- and high-magnification SEM images of hollow spindle-like and cobblestone-like Sb2O3 microstructures, respectively. Fig. a shows that the as-prepared product exists a ...great deal of uniform broken spindle-like structures in high yield, which confirms the formation of hollow structures. Fig. b shows HRSEM images of the amplified morphology of the pore about 300nm in diameter and the surface of the sample is very rough, indicating that the microspindle is composed of many smaller homogeneous nanoparticles. Fig. c and d show that the cobblestone-like microstructure is in diameter of about 3μm and the surface of an individual cobblestone-like Sb2O3 particle is not very smooth, covered with uneven salience. Display omitted
▶ We report the fabrication of novel uniform hollow spindle-shaped and cobblestone-shaped microarchitectures by using CTAB as a soft-template in mixed solvents via a facile hydrothermal synthetic method. ▶ We have varied different reaction parameters such as the reaction temperature and time to study their effect on the size and shape of the formed Sb2O3 morphology. ▶ The possible mechanisms leading to spindle-shaped and cobblestone-shaped microarchitectures were proposed, respectively. ▶ In addition, variations of the crystal structure and morphology of the samples were systematically investigated using XRD, SEM, TEM, BET and micro-Raman spectroscopy.
Hollow spindle-like and cobblestone-like Sb2O3 microstructures, have been successfully synthesized via a hydrothermal method by using cetyltrimethylammonium bromide (CTAB) as soft-templates. Results from XRD, SEM, TEM, Raman and BET showed that experimental parameters, such as the reaction temperature and time, played crucial roles in the respective morphological control of Sb2O3 microstructures. On the basis of these results, possible growth mechanisms for the formation of hollow spindle-like and cobblestone-like microstructures are presented and discussed.
Cobalt sulfide and molybdenum sulfide, with high theoretical capacities, have been considered as one of most promising anode materials for lithium‐ion batteries (LIBs). However, the poor cyclability ...and low rate performances originating from the large volume expansion and poor electrical conductivity extremely inhibit their practical application. Here, the electrochemical performances are effectively improved by growing amorphous cobalt sulfide and molybdenum sulfide onto amorphous carbon‐coated multiwalled carbon nanotubes (CNTs@C@CoS2 and CNTs@C@MoS2). The CNTs@C@CoS2 presents a high reversible specific capacity of 1252 mAh g−1 at 0.2 Ag−1, excellent rate performance of 672 mAh g−1 (5 Ag−1), and enhanced cycle life of 598 mAh g−1 after 500 cycles at 2 Ag−1. For CNTs@C@MoS2, it exhibits a specific capacity of 1395 mAh g−1, superior rate performance of 727 mAh g−1 at 5 Ag−1, and long cycle stability (796 mAh g−1 after 500 cycles at 2 Ag−1). The enhanced electrochemical properties of the electrodes are probably ascribed to their amorphous nature, the combination of CNTs@C that adhered and hindered the agglomeration of CoS2 and MoS2 as well as the enhanced electronic conductivity.
Hybrid power: Amorphous metal sulfides, anchored on carbon‐coated carbon nanotubes, are designed and fabricated through a facile and effective procedure. Such amorphous structures of CoS2 and MoS2, adhered to CNTs@C, which hinders the agglomeration of CoS2 and MoS2, are beneficial for improving the electrochemical performance of the electrodes.
Solar-driven water evaporation is a promising method to address the growing freshwater crisis. Materials with excellent photothermal conversion property and their incorporation into high-efficiency ...devices are the key to solving such crisis. Herein, a flexible architecture featuring uniformly distributed Ag nanoparticles within three-dimensional (3D) carbonized melamine foams (CMF) is proposed, which combines the merits of CMF's porous structure and Ag's plasmonic optical property to efficiently convert light to heat. Packing such 3D CMF@Ag with a melamine foam (MF) as the water absorption layer, solar-driven water evaporation with high efficiency is achieved. With 1 kW m−2 solar illumination on pure tap water, wet fine sand and xalsonte, the fully packed device exhibits evaporation rates of 2.12, 2.14 and 2.39 kg m−2 h−1 and photothermal efficiency of 102.99%, 105.83% and 119.46%, respectively. The enhanced water evaporation performance is ascribed to the synergistic effect of the efficient photothermal conversion of CMF@Ag layer, the strong water absorption/transfer ability of the MF layer, the tightly integrated CMF/MF interface and the environmental energy-assisted means. Equivalently important is the 3D porous structure of CMF that increases the scattering of light and reduces the water vaporization enthalpy. By demonstrating this unique design capable of scalable processing and packing, we expect it to be a promising candidate for efficient water purification applicable to various water sources.
•A flexible 3D CMF@Ag/MF setup was designed for solar steam generation.•A high evaporation rate (2.39 kg m−2 h−1) was achieved under 1 sun for wet xalsonte.•The conversion efficiency of the setup reaches as high as 119.46% under 1 sun.•The mechanisms of the enhanced solar energy conversion were proposed.•The device can absorb extra thermal energy from the external environment.
Display omitted
► We report the fabrication of single crystalline CdTe branched nanowires and well-aligned nanorod arrays via a facile chemical vapor deposition synthetic method. ► Morphology, ...composition, microstructure and optical property of CdTe branched nanowires and nanorod arrays were researched. ► The formation mechanisms of the CdTe branched nanowires and nanorod arrays were proposed.
Single crystalline CdTe branched nanowires and well-aligned nanorod arrays were simultaneously synthesized by a simple chemical vapor deposition (CVD) technique. X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and selected area electronic diffraction (SAED) were used to study the crystalline structure, composition and morphology of different samples. Vapor–liquid–solid (VLS) and vapor–solid (VS) processes were proposed for the formation of the CdTe branched nanowires and nanorod arrays, respectively. As-grown CdTe nanorod arrays show a strong red emission band centered at about 620
nm, which can be well fitted by two Gaussian curves centered at 610
nm and 635
nm, respectively.
Direct Z-scheme NiTiO3/g-C3N4 heterojunctions were successfully assembled by using simple calcination method and the photoelectrochemical and photocatalytic performance were investigated by light ...emitting diode (LED). The photoanode composed by the heterojunction with about 50 wt % NiTiO3 content exhibits the best photoelectrochemical activity with photoconversion efficiency up to 0.066%, which is 4.4 and 3.13 times larger than NiTiO3 or g-C3N4. The remarkably enhanced photoelectrochemical and photocatalytic activity of the heterojunction can be due to the efficiently photogenerated electron–hole separation by a Z-scheme mechanism.
PDF