Display omitted
► TiO2/WO3 composite microspheres were prepared by ultrasonic spray pyrolysis method. ► Crystal phase evolution of WO3 from amorphous to orthorhombic was observed with the increase of ...its content. ► TiO2–2% WO3 showed higher activity than TiO2 in CO2 production and acetaldehyde degradation. ► Electron storage in WO3 had detrimental effect to the complete mineralization of acetaldehyde.
Heterostructured TiO2/WO3 porous microspheres with W/Ti molar ratio of 2, 4, and 10% (TW-2, TW-4, TW-10, respectively) were prepared by ultrasonic spray pyrolysis of aqueous suspension of Degussa P25 particles containing ammonium tungstate. Crystal phase evolution of WO3 from amorphous to orthorhombic was observed with the increase of its content. TiO2/WO3 heterostructured microspheres displayed higher photocatalytic activity towards acetaldehyde degradation than pure TiO2 due to the enhanced charge separation by TiO2/WO3 heterojunction, but only the TW-2 microspheres with amorphous WO3 phase displayed faster generation of CO2 and free hydroxyl radicals than TiO2 (TW-0) micropheres. Photochromism was observed on the TW-4 and TW-10 microspheres due to electron accumulation in orthorhombic WO3, but not observed on the TW-2 with amorphous WO3. These observations suggest that the influence of WO3 on the photocatalytic activity of TiO2 is complicated, and should be related to the crystal phase and electron accumulation ability of WO3, as well as the degradation mechanism of pollutants.
Display omitted
► One-step solvothermal route to RGO/CdS hybrid materials. ► The hybrid materials exhibit an enhanced photocatalytic degradation activity for MB. ► The optimum loading amount of RGO ...is 5.0wt%. ► The RGO retards the charge recombination of CdS enhancing the degradation efficiency.
Reduced graphene oxide/cadmium sulfide (RGO/CdS) hybrid material was synthesized by a one-step solvothermal method, wherein graphene oxide (GO) was a supporting material on which CdS nanoparticles were distributed homogeneously, and cadmium acetate (Cd(Ac)2·2H2O) was used as the CdS precursor. The supporting material RGO for CdS nanoparticles effectively enhanced their photocatalytic activities for the photodegradation of methylene blue in the aqueous solution. The optimum weight ratio of the GO to CdS in the hybrid material was 5.0%, which exhibited an excellent photodegradation efficiency (94%) and a better removal efficiency of total organic carbon (TOC) (57%), about 2.5 times and 5.1 times higher than that of pure CdS nanoparticles, respectively, under visible light (VL) irradiation. This improved photodegradation efficiency could be attributed to the increased adsorbability for methylene blue molecules, light absorption levels located in visible region, high charge transfer and separation ability, due to the introduction of a two-dimensional RGO network.
Micron-sized CNTs/Cu2O composite powder prepared by Molecular Level Mixing (MLM) was mixed with flaked Cu-1.0 wt% Ti (Cu-1.0 Ti) matrix powders by low-energy ball milling. After reduction and hot ...pressing, CNTs/Cu-Ti composites were fabricated. Microstructure and mechanical properties of the composites were characterized by SEM, EDS, HRTEM, hardness and tensile tests, etc. The results showed that mechanical properties of the CNTs/Cu-Ti composites were enhanced compared with alloy matrix, which were ascribed to the well-distributed of CNTs and strong bonding interface with the matrix by the formation of a transition layer of TiC. Finally, strengthening mechanisms were discussed.
•CNTs reinforced Cu-Ti composites were fabricated by powder metallurgy process.•The Molecular Level Mixing method was used to disperse CNTs effectively.•CNTs was mixed with metal matrix in the form of micron-sized CNTs/Cu2O powders.•The formation of TiC improved the interface bonding strength of composites.
Exploration of optoelectronic memristors with the capability to combine sensing and processing functions is required to promote development of efficient neuromorphic vision. In this work, the authors ...develop a plasmonic optoelectronic memristor that relies on the effects of localized surface plasmon resonance (LSPR) and optical excitation in an Ag–TiO2 nanocomposite film. Fully light‐induced synaptic plasticity (e.g., potentiation and depression) under visible and ultraviolet light stimulations is demonstrated, which enables the functional combination of visual sensing and low‐level image pre‐processing (including contrast enhancement and noise reduction) in a single device. Furthermore, the light‐gated and electrically‐driven synaptic plasticity can be performed in the same device, in which the spike‐timing‐dependent plasticity (STDP) learning functions can be reversibly modulated by visible and ultraviolet light illuminations. Thereby, the high‐level image processing function, i.e., image recognition, can also be performed in this memristor, whose recognition rate and accuracy are obviously enhanced as a result of image pre‐processing and light‐gated STDP enhancement. Experimental analysis shows that the memristive switching mechanism under optical stimulation can be attributed to the oxidation/reduction of Ag nanoparticles due to the effects of LSPR and optical excitation. The authors' work proposes a new type of plasmonic optoelectronic memristor with fully light‐modulated capability that may promote the future development of efficient neuromorphic vision.
A novel plasmonic optoelectronic memristor is demonstrated for the first time relying on localized surface plasmon resonance (LSPR) effect. Both fully light‐modulated and light‐gated electrically‐driven synaptic modulation can be implemented in such a single device. Furthermore, combination of visual sensing, low‐level (contrast enhancement and noise reduction), and high‐level image processing (image recognition) promotes the development of efficient neuromorphic vision.
Display omitted
•Introduction of dye and construction of superparticles improved photothermal effect.•The Fe3O4-IR806 superparticles exhibited negligible toxicity.•A highly efficient ...photothermal-photodynamic therapy of glioma was performed.
It is challenging and urgent in neurosurgery to improve therapeutic effect of the most common and lethal malignant glioma in central nervous system. The superadditive therapeutic effect of photothermal therapy and photodynamic therapy holds great promise. Herein, a highly efficient photothermal-photodynamic therapy nanoplatform was developed on the basis of Fe3O4-IR806 superparticles. The introduction of the near-infrared (NIR) dye IR806 and the fabrication of the self-assembled structure of the superparticles warrant 3.5 times increase in the photothermal conversion efficiency compared with the Fe3O4 nanoparticles. The Fe3O4-IR806 superparticles generated reactive oxygen species (ROS) with the NIR light irradiation by virtue of the dye IR806. Both in vitro and in vivo experiments demonstrated that the Fe3O4-IR806 superparticles exhibited negligible toxicity. The Fe3O4-IR806 superparticles efficiently inhibited the cultured glioma cells via photothermal ablation and ROS cytotoxicity in vitro, as well as suppressed the bearing glioma growth in vivo with the NIR light induction. Our results highlight the promise of the Fe3O4-IR806 superparticles for improved photothermal-photodynamic therapy of cancer.
•The HfO2−x based RRAMs exhibit high uniformity by Ar plasma.•The low-power multilevel memory is achieved by Ar plasma.•The reliable resistive switching behaviors depend on interface changes at ...Au/HfO2−x.
We demonstrated an effective method of Ar surface plasma treatment (SPT) to improve the resistive switching (RS) uniformity of HfO2−x based resistive random access memory (RRAM) device. More importantly, the operation of multilevel RRAM and low power consumption can be further achieved by reliable RS, which enabled to obtain five distinguishable low resistance states and can be operated with a low power consumption of ∼30 pJ. The results of atomic force microscope and X-ray photoelectron spectroscopy analysis confirmed that the Ar SPT induced more oxygen defects and higher roughness on the surface, which decreased the migration barrier of oxygen migration and some tips below the electrode. Eventually, a moderate forming process and local electric-field enhancement around these tips were obtained, accounting for the improvement of RS uniformity. This method could be promising to develop RRAM with high uniformity for the low-power multilevel memory applications.
Abstract Electrochemical reduction of carbon dioxide into ethylene, as opposed to traditional industrial methods, represents a more environmentally friendly and promising technical approach. However, ...achieving high activity of ethylene remains a huge challenge due to the numerous possible reaction pathways. Here, we construct a hierarchical nanoelectrode composed of CuO treated with dodecanethiol to achieve elevated ethylene activity with a Faradaic efficiency reaching 79.5%. Through on in situ investigations, it is observed that dodecanethiol modification not only facilitates CO 2 transfer and enhances *CO coverage on the catalyst surfaces, but also stabilizes Cu(100) facet. Density functional theory calculations of activation energy barriers of the asymmetrical C–C coupling between *CO and *CHO further support that the greatly increased selectivity of ethylene is attributed to the thiol-stabilized Cu(100). Our findings not only provide an effective strategy to design and construct Cu-based catalysts for highly selective CO 2 to ethylene, but also offer deep insights into the mechanism of CO 2 to ethylene.
A flexible high-sensitive wearable strain sensor has been fabricated based on flexible rubrene single crystal as sensing material. Different from the previously extensively reported thin-film organic ...field-effect transistor (OFET) based strain sensors, the present sensing system is based on the modulation of the intermolecular distance of organic crystal under strain, and applied the two-terminal device configuration. This new device designed with the simple device configuration exhibits the comparable sensing performance with the conventional thin-film OFET based strain sensors, including high sensitivity (gauge factor = 279), wide detection range, and high cycle stability. Furthermore, the rubrene single-crystal strain sensors can accurately detect the motions of the body, such as swallowing saliva of throat, inside-bending and outside-bending of finger, and multi-angle bending of arm. Such a new-type device design opens a new powerful route to realize ultra-sensitive strain detection for promising applications in artificial intelligence and healthcare systems.
Display omitted
•The flexible organic strain sensor applies the two-terminal device configuration.•The strain sensor that uses organic crystal as the sensing element is presented.•The sensor exhibits the comparable sensing performance with the thin-film sensors.•The high gauge factor has exceeded that of the organic thin-film strain sensor.•The organic crystal strain sensor can accurately detect the motions of the body.
Gas sensors based on organic semiconductor have recently attracted much attention due to their inherent advantages, especially excellent flexibility and good selectivity. However, the gas species ...identification with high sensing response remains a key subject for organic gas sensors. Herein, a ZnPc single nanobelt field-effect transistor with the gas dielectric was fabricated and exhibited excellent gas sensing performance at room temperature. The sensors show the high response with 220% to 10 ppm NO 2 and 3566% to 20 ppm H 2 S, and the low detection limit down to 50 ppb towards NO 2 /H 2 S, which surpass most reported room-temperature organic-based NO 2 /H 2 S sensors. Further, our single device realized accurate gas selective identification among NO 2 , SO 2 and H 2 S with 92% success ratio in LDA feature space.
Colored wide‐bandgap semiconductor oxides with abundant mid‐gap states have long been regarded as promising visible light responsive photocatalysts. However, their catalytic activities are hampered ...by charge recombination at deep level defects, which constitutes the critical challenge to practical applications of these oxide photocatalysts. To address the challenge, a strategy is proposed here that includes creating shallow‐level defects above the deep‐level defects and thermal activating the migration of trapped electrons out of the deep‐level defects via these shallow defects. A simple and scalable solution plasma processing (SPP) technique is developed to process the presynthesized yellow TiO2 with numerous oxygen vacancies (Ov), which incorporates hydrogen dopants into the TiO2 lattice and creates shallow‐level defects above deep level of Ov, meanwhile retaining the original visible absorption of the colored TiO2. At elevated temperature, the SPP‐treated TiO2 exhibits a 300 times higher conversion rate for CO2 reduction under solar light irradiation and a 7.5 times higher removal rate of acetaldehyde under UV light irradiation, suggesting the effectiveness of the proposed strategy to enhance the photoactivity of colored wide‐bandgap oxides for energy and environmental applications.
Solution plasma brings H doping into oxygen vacancy type TiO2. The H dopant bridges the gap between the oxygen vacancy (Ov) and conduction band (CB), resulting in photothermal extraction of trapped electrons at the Ov to CB. The solution plasma strategy endows a 300 times higher conversion rate for CO2 reduction under solar light at 393 K than that at 298 K.
PDF
