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Plasmonic nanostructures have received significant attention in the field of solar-to-fuels conversion, because they can collect and utilize abundant low-energy photons to generate high-energy hot electrons for producing green chemical fuels. However, the ultrafast relaxation process of hot electron often leads to poor quantum yields of plasmonic nanostructures. Herein, we construct the one-dimensional W 18 O 49 /Carbon heterostructure for employing low-cost electrospun carbon fibers as the “electron mediator” to hinder the relaxation of hot electron in plasmonic W 18 O 49 nanowires. We confirm that the IR-excited plasmonic hot electrons in W 18 O 49 nanowires can quickly transfer to carbon fibers within only ∼50 fs in the W 18 O 49 /C heterostructure. This kinetics time is much shorter than the relaxation time of these hot electrons from high-energy surface plasmon (SP) to the ground state in W 18 O 49 nanowires (∼5.5 ps). As a result, upon low-energy IR-light excitation, the W 18 O 49 /C heterostructures exhibit nearly 2-fold enhancement on the catalytic H 2 production from ammonia borane as compared to single W 18 O 49 nanowires. Wavelength-dependent catalytic tests further indicate that this plasmon-enhanced catalytic activity is induced by the ultrafast transport process of plasmonic hot electron due to the localized surface plasmon resonance. [ABSTRACT FROM AUTHOR]

Rational arrangement of nanosized semiconductor components in the multi-heterojunction photocatalyst can lead to the formation of a high-speed transport channel for charge-carriers separation and migration, which provides a promising way to achieve excellent photocatalytic efficiency for solar fuels generation. Herein, we develop a photo-assisted self-optimization strategy to re-build the charge-carriers transport channel in the copper species nanocrystals/TiO 2 electrospun nanofibers with the organic hydrogen-carrier molecules as the photo-reactants. As a result of the dynamics difference of the excitons migration during the photocatalytic process, the binary CuO/TiO 2 heterojunction nanofibers are recrystallized to form the quaternary Cu/Cu 2 O/CuO/TiO 2 multi-heterojunction nanofibers that exhibits a higher rate constant ( ∼ 1.7 × 10 8 S − 1 ) for the interfacial electron-transfer than the former nanofibers ( ∼ 0.7 × 10 8 S − 1 ) due to the improved charge-carriers transport channel. In this way, a 40-fold enhanced H 2 generation rate was observed on the recrystallized nanofibers photocatalyst during the photocatalytic decomposition of formic acid as compared to the pure TiO 2 nanofibers. Our work presents an available paradigm to skillfully use a transient photo-physicochemical process to mildly engineer a high-quality charge-carriers transport channel in the hetero-nanophotocatalyst for realizing an optimal photocatalytic performance. [ABSTRACT FROM AUTHOR]

Direct evidence of plasmon-enhanced 4-nitrophenol (4-NP) reduction is observed in a photo-assisted catalytic process with the NaBH 4 as the electron donator by using the Ag nanoparticles (AgNPs) supported onto a flexible and processable polyacrylonitrile (PAN) microfibrous network. The Ag/PAN composite fibrous networks exhibit certain activity for 4-NP reduction in general condition. Significantly, when the beam irradiation is introduced to excite the surface plasmon resonance (SPR) of AgNPs, we observed an enhanced catalytic activity for 4-NP reduction (1 ∼ 3 times). Meanwhile, the enhancement factors for the catalytic kinetic constants are directly correlated with the SPR absorption spectra of AgNPs. Further in-depth studies by adjusting the experiment conditions reveal that the SPR-induced ultrafast thermal effect of AgNPs is responsible for the enhanced catalytic activity that can not be nevertheless initiated or magnified by the hot plasmonic electrons from Ag. By combining with the theoretical analyses, we propose that this plasmon enhancement is ascribed to the promoted diffusion rate of reactants in the solution driven by increasing the local temperature around the AgNPs on the basis of SPR-enhanced electric field. Our present work provides a new sight to understand the plasmonic enhancement of metal-related catalytic reactions, and would also create more opportunities to guide the design and fabrication of high-performance plasmonic catalysts with excellent recycling property. [ABSTRACT FROM AUTHOR]

We present high-yield hydrogen production through selective photocatalytic decomposition of formic acid by using electrospun TiO 2 nanofibers decorated with AuPd bimetallic alloy nanoparticles under simulated sunlight irradiation. By using only 5 mg of the AuPd/TiO 2 nanofibers containing the 0.75% Au and 0.25% Pd, we could achieve an optimal H 2 generation rate of 88.5 μmol h −1 with an apparent quantum yield at 365 nm as 15.6%, which is higher than that of the Pd/TiO 2 and Au/TiO 2 nanofibers by a factor of 1.6 and 4.5, respectively. The enhanced photocatalytic decomposition of formic acid for H 2 generation could be attributed to the stronger electron-sink effect of AuPd alloy nanoparticles, the high selectivity of Pd for the dehydrogenation of formic acid, and the surface plasmon resonance effect of Au. More importantly, we demonstrate that the photocatalytic processes enable re-activation of the AuPd nanoparticles that were poisoned by CO during thermal decomposition of formic acid. As such, the presented AuPd/TiO 2 nanofibers are promising materials for re-generation of H 2 under mild conditions from liquid storage carrier of hydrogen. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) Pt/TiO 2 hybrid nanofibers (HNFs) with different concentrations of Pt were fabricated by a facile two-step synthesis route combining an electrospinning technique and calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) results showed that the Pt nanoparticles (NPs) with the size of 5–10 nm were well dispersed in the TiO 2 nanofibers (NFs). Further investigations from the UV–Vis diffuse reflectance (DR) and X-ray photoelectron spectroscopy (XPS) analysis revealed that some Pt ions were incorporated into the TiO 2 lattice as Pt 4+ state, which contributed to the visible light absorption of TiO 2 NFs. Meanwhile, the Pt 2+ ions existing on the surface of Pt NPs resulted in the formation of Pt–O–Ti bond at Pt NPs/TiO 2 NFs interfaces that might serve as an effective channel for improving the charge transfer. The as-electrospun Pt/TiO 2 HNFs exhibited remarkable activities for photocatalytic H 2 evolution under visible light irradiation in the presence of l -ascorbic acid as the sacrificial agent. In particular, the optimal HNFs containing 1.0 at% Pt showed the H 2 evolution rate of 2.91 μmol h −1 and apparent quantum efficiency of 0.04% at 420 nm by using only 5 mg of photocatalysts. The higher photocatalytic activity could be ascribed to the appropriate amount of Pt ions doping and excellent electron-sink effect of Pt NPs co-catalysts. [ABSTRACT FROM AUTHOR]

Abstract: Nanofibers and nanoribbons of poly (methyl methacrylate) (PMMA)/Eu3+ ions composites with different concentration of Eu3+ ions were successfully prepared by using a simple electrospinning technique. From the results of scanning electron microscopy and energy-dispersive X-ray spectroscopy, we found that the morphology of the as-electrospun PMMA/Eu3+ ions composites could be changed from fiber to ribbon structure by adjusting the concentration of Eu3+ ions in the electrospun precursor solution. The coordination between the Eu3+ ions and PMMA molecules were investigated by Fourier transform infrared spectroscopy and differential thermal analysis. The photoluminescence (PL) properties of the as-electrospun PMMA/Eu3+ ions composites were studied in comparison to those of the Eu(NO3)3 powder. It was showed that the 5D0–7F J (J =0, 1, 2, 3, 4) emission appeared in the PL spectra of the as-electrospun PMMA/Eu3+ ions composites, whereas the 5D0–7F0 emission was completely absent in the PL spectra of Eu(NO3)3 powder due to the different local environments surrounding Eu3+ ions. It was interesting to note that the intensity ratios of the electric–dipole and magnetic–dipole transitions for the PMMA/Eu3+ ions composites could be enhanced significantly by increasing electrospinning voltage. [Copyright &y& Elsevier]

Abstract: In this work, V-doped TiO2 nanofibers with different V contents have been fabricated by an electrospinning technique. The as-prepared nanofibers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS), and UV–Vis diffuse reflectance (DR) spectroscopy. The results indicated that the V4+ or V5+ ions were successfully incorporated into the crystal lattice of anatase TiO2 nanofibers. Meanwhile, the V doping could extend the visible light absorption of TiO2 nanofibers. The photocatalytic experiments indicated that the obtained V-doped TiO2 nanofibers possessed high activity for the photodegradation of organic pollutant methylene blue (MB). Especially, the 1.0 and 5.0wt.% V-doped TiO2 nanofibers exhibited the best catalytic activity under visible and ultraviolet (UV) light irradiation, respectively. Also, these nanofibers could be easily recycled without a decrease of the photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Highly dispersed ZnO quantum dots (QDs) in poly(vinyl pyrrolidone) (PVP) nanofibers have been successfully prepared by electrospinning technique. The structure and optical properties were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), resonant Raman spectra, Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric and differential thermal analysis (TG–DTA), ultraviolet (UV)–vis absorption spectra, and photoluminescence (PL) spectra. In the PVP/ZnO QDs composite nanofibers, PVP molecules could effectively prevent the aggregation of ZnO QDs and passivate the surface defects of ZnO QDs. Thus, by comparing ZnO QDs, the composite nanofibers exhibited a blue-shifted band gap and enhanced ultraviolet (UV) emission. Furthermore, the composite nanofibers prepared at higher voltage showed more intense UV emission than which obtained at lower voltage, suggesting that the UV emission intensity of the composite nanofibers could be controlled by adjusting the electrospinning voltage. [Copyright &y& Elsevier]

The tubular nanocomposite with well-dispersed distribution of small gold nanoparticles (AuNPs) assembled on the inside and outside surfaces of silica nanotubes (SNTs) was fabricated by combining the single capillary electrospinning technique and an in situreduction approach. The AuNPs/SNTs nanocomposite exhibited a good catalytic activity for reduction of 4-nitrophenol (4-NP). [ABSTRACT FROM AUTHOR]

With the rapid development of industry, organic pollutants and bacterial contamination in water resources are becoming increasingly severe. Photocatalysis is an effective approach to address this problem. ZnO, as a traditional n- type semiconductor photocatalyst, has a relatively wide bandgap, which results in a narrow range of light absorption and quick recombination of photogenerated charge carriers, thus limiting its development. In this work, we constructed p -type CuO/ n -type ZnO heterojunction nanofibers (HNFs) to extend the light harvesting range and improve the migration and separation of the photoinduced electrons and holes across the hetero-interface through. Afterwards, Ag nanoparticles were introduced into above HNF matrix to reinforce the photocatalytic activity. Results showed that, upon simulated sunlight irradiation, the Ag NPs-decorated p- type CuO/ n- type ZnO HNFs exhibited enhanced photocatalytic activities. After 20 min of simulated sunlight irradiation, approximately 98.5% of MB was degraded by 1.0 at% Ag NPs-decorated p- type CuO/ n- type ZnO HNFs. Additionally, after 10 min of irradiation, the disinfection efficiency of HNFs for Escherichia coli was > 99.99%. It is worth noting that this study has opened up a new pathway for the rational design of p-n junction photocatalysts with superior charge transfer properties, to achieve remarkable photocatalytic disinfection and degradation activities. [Display omitted] • A p -type CuO/ n -type ZnO photocatalyst was prepared, leading to the broadening of photoabsorption in the visible region. • The CuO/ZnO nanofibers possess excellent photocatalytic activity for the degradation of MB and disinfection of E. coli. • To further enhance the activity of binary photocatalysts, Ag nanoparticles were successfully modified on CuO/ZnO HNFs. • Ag nanoparticles-modified CuO/ZnO HNFs photocatalysts exhibit rapid dye degradation and bactericidal activity (<30 min). [ABSTRACT FROM AUTHOR]

• TiO 2 /Cu 2 O/CuO CNFs is produced via a photoinduced phase-transition on the TiO 2 /CuO CNFs. • The TiO 2 /Cu 2 O/CuO CNFs exhibited the enhanced sensing property for glucose. • The sensitivity of TiO 2 /Cu 2 O/CuO CNFs depends on the TiO 2 content in the CNFs. • The sensing property of TiO 2 /Cu 2 O/CuO CNFs electrode is recoverable via the light irradiation. • The CNFs electrode possesses a good long-term stability, high anti-interference ability, and good reproducibility. The TiO 2 /Cu 2 O/CuO composite nanofibers (CNFs) were obtained via the photoinduced phase-transition process occurring in the electrospun TiO 2 /CuO CNFs. The TiO 2 /Cu 2 O/CuO CNFs electrode showed the higher sensitivity (2074.7 µA·mM−1·cm−2; 0–2 mM) than the pure CuO NFs, TiO 2 NFs, and TiO 2 / CuO CNFs electrodes, respectively. The enhanced glucose sensing performance is attributed to the existence of multiple valence-states and redox-couples in TiO 2 /Cu 2 O/CuO CNFs to promote the redox reaction. [Display omitted] Constructing metal-oxide-based composites with the multiple valence-states and redox-couples has been proved as an effective strategy to enhance the performance of non-enzymatic glucose sensing. Herein, we report a mild and efficient method to prepare multiple-valent copper-based oxide composite nanofibers (Cu x O CNFs) through introducing the TiO 2 photosensitizer into the CuO NFs for actuating the localized phase transition from tenorite CuO (Cu2+) to cuprite Cu 2 O (Cu+) upon UV–visible light irradiation. The sensitivity of the obtained TiO 2 /Cu 2 O/CuO CNFs for glucose sensing (0–2 mM) could be enhanced by 1.12–1.31 times as compared to that of the TiO 2 /CuO CNFs. The enhanced sensitivity is dependent on the TiO 2 -content in the primal TiO 2 /CuO CNFs. When introducing 5.0 at.% of TiO 2 into the CuO nanofibers, the photoinduced phase-transition process could result in the formation of optimal TiO 2 /Cu 2 O/CuO CNFs with the component ratio of Cu 2 O to CuO at 0.46:1. This TiO 2 /Cu 2 O/CuO CNFs (2074.7 µA·mM−1·cm−2; 0.25 µM) exhibited nearly 1.32-fold improvement on the sensitivity and 3.0-fold enhancement on the detection limit as compared to the corresponding values of the pure CuO electrospun nanofibers (1581 µA·mM−1·cm−2; 0.75 µM). After the continuous measurements for 14 days, the sensitivity of the optimal sample could maintain 89.4% of its initial value. Notably, its sensitivity could be further recovered to 97.4% of the initial value after UV–visible light irradiation for 1 h. [ABSTRACT FROM AUTHOR]

Abstract: Zn2TiO4@carbon core/shell nanofibers (Zn2TiO4@C NFs) with different thickness of carbon layers (from 2 to 8nm) were fabricated by combining the electrospinning technique and hydrothermal method. The results showed that a uniform carbon layer was formed around the electrospun Zn2TiO4 nanofiber (Zn2TiO4 NFs). By adjusting the hydrothermal fabrication parameters, the thickness of carbon layer varied linearly with the concentration of glucose. Furthermore, the core/shell structure formed between Zn2TiO4 and carbon enhanced the charge separation of pure Zn2TiO4 under ultraviolet excitation, as evidenced by photoluminescence spectra. The photocatalytic studies revealed that the Zn2TiO4@C NFs exhibited enhanced photocatalytic efficiency of photodegradation of Rhodamine B (RB) compared with the pure Zn2TiO4 NFs under ultraviolet excitation, which might be attributed to the high separation efficiency of photogenerated electrons and holes based on the synergistic effect between carbon and Zn2TiO4. Notably, the Zn2TiO4@C NFs could be recycled easily by sedimentation without a decrease of the photocatalytic activity. [Copyright &y& Elsevier]

Abstract: The 3D open Bi2MoO6/ZnTiO3 hierarchical heterostructures with Bi2MoO6 ultrathin nanosheets (<10nm) grown on hexagonal-phase ZnTiO3 nanofibers were fabricated by combining the electrospinning technique and solvothermal method. And, the Bi2MoO6/ZnTiO3 hierarchical heterostructures had remarkable light absorption in the visible region. The photocatalytic studies revealed that the hierarchical heterostructures system exhibited exceptional photocatalytic activity in visible-light degradation of Rhodamine B, which might be attributed to the synergistic system with excellent charge separation characteristics and the unique morphology of Bi2MoO6 nanosheets with the extended absorption in the visible light region. What is more, the 3D open structure supported on nanofibrous candidates possessed large surface areas and excellent recyclability. [Copyright &y& Elsevier]

Abstract: A novel photocatalyst of nanostructured cadmium phthalocyanine (CdPc) immobilized on the surface of polyacrylonitrile (PAN) nanofibers had been successfully fabricated by a simple combination of electrospinning technique and the solvent-thermal process. FE-SEM micrographs indicated that the nanostructured CdPc uniformly immobilized on the surface of PAN nanofibers without agglomeration. And the obtained CdPc/PAN composite nanofibers exhibited high visible light photocatalytic activity for the degradation of rhodamine B. Moreover, this photocatalyst could be easily separated for reuse due to the one-dimensional nanostructural property of the CdPc/PAN composite nanofibers. [Copyright &y& Elsevier]

Abstract: Tin oxide (SnO2)/carbon nanofibers (CNFs) heterostructures were fabricated by combining the versatility of the electrospinning technique and template-free solvent–thermal process. The results revealed that the SnO2 nanostructures were successfully grown on the primary electrospun carbon nanofibers substrates. And, the coverage density of SnO2 nanoparticles coating on the surface of the CNFs could be controlled by simply adjusting the mass ratio of CNFs to SnCl4·5H2O in the precursor during the solvent–thermal process for the fabrication of SnO2/CNFs heterostructures. The electrochemical performances of the SnO2/CNFs heterostructures as the electrode materials for supercapacitors were evaluated by cyclic voltammetry (CV) and galvanostatic charge–discharge measurement in 1M H2SO4 solution. At different scan rates, all the samples with different coverage densities of SnO2 showed excellent capacitance behavior. And, the sample CS2 (the mass ratio of CNFs to SnCl4·5H2O reached 1:7) exhibited a maximum specific capacitance of 187F/g at a scan rate of 20mV/s. Moreover, after 1000 cycles, the specific capacitance retention of this sample was over 95%. The high capacitive behavior could be ascribed to the low resistance of SnO2/CNFs heterostructures and rapid transport of the electrolyte ions from bulk solution to the surface of SnO2. [Copyright &y& Elsevier]