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Li0.45V2O5·0.89H2O (LVO) was successfully synthesized by wet-mixing of LiOH·H2O and V2O5, with subsequent hydrothermal method for the first time. The hydrated lithium ions as the intercalated guest species were inserted into the V2O5 interlayer. The as-obtained LVO with a stable lamellar structure, enlarged interlayer space, weak interlayer repulsive force and low molecular weight, which shows a specific capacitance of 403 mAh g−1 at 0.1 A g−1, excellent rate capability and longlifespan with capacity retention of 86% over 1000 cycles at 10 A g−1. Furthermore, the LVO-based AZIBs possess a synergistic insertion mechanism of Zn2+ and H+, that is the reason for its superior performance. This work provides an efficient design strategy for synthesizing advanced cathode materials for the high-performance Zn2+ energy storage system.

Adjusting the interlayer structure of carbon nitride is expected to adjust its physicochemical properties, thereby enhancing photocatalytic activity. In this paper, alkaline metal ion-intercalated carbon nitride was prepared by molten salt co-pyrolysis. Alkali metal ions acted as mediators to provide a new migration path for the photogenerated electrons of g-C3N4. The intercalation of K+ and Na+ reduced the bandgap value of carbon nitride, expanded the visible light absorption range, and promoted the separation and migration of charge carriers. As a result, the hydrogen production rate of DCN1 reached 500 μmol g−1 h−1, which was 10 times than that of pristine g-C3N4. Experimental and theoretical methods were used to explain the improvement of photocatalytic efficiency after K+ and Na+ were intercalated into the interlayer of g-C3N4. Our work provided a new idea for the design of high-efficiency hydrogen evolution photocatalysts via intercalation method.

For applications in thermal structure engineering, static and dynamic mechanical properties of 3D braided SiC/SiC composites after oxidation were investigated and the effects of interface between fibers and matrix were revealed. The results showed that composites with combined (PyC + SiC) multilayer interface (denoted as K–C/S) were superior to those with a single interlayer or without an interlayer. After oxidation, K–C/S showed the least weight changes, the highest flexure strength, small internal friction, and highest storage modulus. The outside SiC interface of K–C/S protected the PyC interface from further oxidation. Thus, K–C/S showed highly advantageous with regard to both static and dynamic properties after oxidation.

Two-dimensional graphene-like hexagonal borophene sheets (HBSs) have a thermodynamically unsteady configuration since boron has one electron less than the carbon in graphene. To overcome this problem, we proposed a novel 2D graphene-like HBS oxide (h-B3O) in theory, which is designed by substituting partial boron atoms in a HBS with oxygen atoms. Molecular dynamics simulations indicate that h-B3O has good thermal stability. Besides, we also explored the potential of h-B3O monolayers as anodes for Li-ion batteries (LIBs) and Na-ion batteries (NIBs) by using first-principles calculations. The results indicated that the h-B3O monolayer has high adsorption energies (-2.33/-1.70 eV for Li/Na), low diffusion barriers (0.67/0.42 eV for Li/Na) and suitable average open-circuit voltages (0.36/0.32 V for LIBs/NIBs). Particularly, h-B3O has a large theoretical specific capacity of 1161 mA h g-1 for LIBs. Thus, benefiting from these characteristics, the h-B3O monolayer is considered as a promising candidate for an anode material for LIBs/NIBs.

Bismuth oxychloride (BiOCl) has great potential as a photocatalytic material. It is worthy to improve its photocatalytic performance by a simple and feasible method. In this work, withered cattail is carbonized directly at 800 ℃ in nitrogen atmosphere to obtain cattail carbon with good conductivity, which could be a good acceptor of photogenerated electrons. Through the one-step facile co-precipitation route with stirring at room temperature followed by the treatment of acetic acid, ultrathin nanosheets of BiOCl were synthesized and grew on the surface of cattail carbon. The BiOCl/cattail carbon composites have well-contacted heterojunction interface, hierarchical structure, high specific surface area and enhanced utilization of visible light, which allow the composites to separate the photogenerated electron-holes efficiently. Thus the BiOCl/cattail carbon composites could show excellent photocatalytic activity, which could remove rhodamine B completely within one hour under visible light. The degradation rate of the composite could achieve about 17 times higher than that of pure BiOCl. Mechanism test showed that both OH and h+ active species could work together to degrade organic pollutants. Therefore, our work combines readily available and inexpensive biochar materials with BiOCl, which provides a strategy for the low-cost synthesis of efficient BiOCl-based photocatalytic materials that can be used in large-scale industrial production to be applied in the treatment of organic wastewater.

The development of high-efficiency anode materials with large capacity, high stability and fast diffusion rates is a key requirement for rechargeable Li-ion and Na-ion batteries (LIBs/NIBs). In this work, the adsorption and diffusion of Li and Na atoms on two-dimensional (2D) Si3N materials is studied using first-principles calculations. The Si3N monolayers have large adsorption energies (2.74 eV for Li and 2.17 eV for Na) and a high theoretical capacity (1772.0 mAh/g for Li and 859.6 mAh/g for Na). Moreover, the low diffusion barriers (0.45 and 0.24 eV) for Li and Na atoms indicate that Si3N has an excellent high charge/discharge capability. In addition, molecular dynamics simulations showed that the structure of the 2D Si3N monolayer with adsorption of 32 Li/Na atoms has a very small change at 400 K due to the large adsorption energies for Li/Na. Owing to its good features, the Si3N monolayer is a highly promising anode material for energy storage devices.

The development of bimetallic-based ternary materials (BTMs) has attracted much attention due to their multi-component flexibility and synergistic effect. Herein, BTM (Ce2Sn2O7) nanoparticles are encapsulated into graphene (Ce2Sn2O7/RGO), which served as a novel anode material for lithium-ion batteries and capacitors (LIBs/LICs). Benefiting from the synergistic effects from two metal elements and the conductive networks of graphene, the optimized Ce2Sn2O7/RGO delivers a reversible capacity of 814.6 mA h g−1 at 0.05 A g−1, good cycling performance with a reversible capacity of 369.5 mA h g−1 after 1500 cycles at 1 A g−1 and a superior rate capability of 432.4 mA h g−1 at 2 A g−1 in Li+ half cells. Meanwhile, the detailed phase transition and kinetics analysis as well as the theoretical calculation are performed to investigate the reaction mechanisms behind the good electrochemical performance. Furthermore, the Ce2Sn2O7/RGO also shows good lithium-ion full cell and capacitor performances coupled with commercial LiCoO2 and activated carbon, respectively, which further demonstrates the application prospect of Ce2Sn2O7/RGO.

We suggest the possibility to build graphene analogue with the planar hexacoordinate wheel-type Fe@B6H6 cluster as the building block through studying theoretically the geometry, stability, and electron structure of its dimer and trimer as well as the dimerization of the two trimers. Employing the dehydrogenation route to polymerization, we can obtain the hexagonal boron sheet that are partly and uniformly filled by Fe atoms in the center of the holes, achieving uniform chemical doping and a very large hexagonal-hole density. Thus, we may offer a novel cluster-assembled material for experimental chemists to construct graphene analogue.

It remains an exciting challenge to achieve a direct production of large quantities of •OH, generated from photogenerated h+ using visible-light-driven photocatalysts fabricated by a one-step metho...

BiOI is a visible photocatalyst towards organic pollutant. In this work, biomass waste (withered typha grass) was used to fabricate nitrogen-doped hierarchical carbon (NHC) by an one-step carbonization route. Then NHC provided a good carrier to load the BiOI semiconductor materials by a green simple co-precipitation method, after adding NaOH solution, the irregular microspheres BiOI/NHC was gradually etched by OH− to form the tremella-like Bi4O5I2/NHC. The well-defined tremella-like Bi4O5I2/NHC invested adequate interface and high particular surface range (SBET: 66 m2 g−1), which is higher than pure BiOI (22 m2 g−1) and Bi4O5I2 (17 m2 g−1). Multiple synergistic effects, such as high SBET can give more dynamic destinations, the special tremella-like structure can assimilate more reflected occurrence light of other nanosheets, low I content can increase the conduction/valence band gap of semiconductor materials and NHC can act as an electron acceptor, making as-prepared Bi4O5I2/NHC composite ideal candidates for photocatalysis. The degradation rate of Bi4O5I2/NHC reaches up to 87.4% of methyl orange in 2 h, which is about 2 times higher than BiOI and Bi4O5I2. Therefore, this work gives a technique to link NHC derived from biomass waste to Bi4O5I2 with highly-efficiency photocatalytic performance.

Two dendritic host materials consisting of non-conjugated adamantane cores and four first-/second-generation carbazole dendrons (Ad-4D1 and Ad-4D2) are developed for efficient solution-processed blue thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs). The dendrimers with three-dimensional geometries, which are constructed through facile one-step palladium-catalyzed C–N coupling reactions involving tetra-substituted adamantane and carbazole dendrons, show high thermal stability and excellent solubility in common organic solvents. The dendrimers possess high triplet energies (ETs) of 2.83–2.95 eV, making them suitable to host blue TADF emitters. Compared with Ad-4D1 with the first-generation dendrons showing a deep highest occupied molecular orbital (HOMO) level of −5.51 eV, Ad-4D2 with the second-generation ones exhibits an elevated HOMO level of −5.32 eV, favorable for hole injection from anode to the emissive layer. Solution-processed blue TADF OLEDs utilizing Ad-4D2 as a host exhibit promising device performance with a maximum luminous efficiency, power efficiency and external quantum efficiency of 44.2 cd A−1, 34.4 lm W−1 and 18.3%, respectively, among the highest values for solution-processed blue TADF OLEDs. This work sheds light on the development of dendritic host materials, as an alternative to soluble small-molecule hosts and polymer hosts, to realize high-efficiency solution-processed TADF OLEDs.

Metal-semiconductor-metal ultraviolet photodetector with different electrode spacing is fabricated on ZnO film, prepared by radio frequency magnetron sputtering technique on a quartz substrate. The responsivity of the ZnO photodetector increased with decreasing electrode spacing for the same bias. Meanwhile, both of the spectral responses show a saturation behavior due to the gain effect dependence on the applied bias voltage. Additionally, more attractive thing is that the rise and fall ratios of responsivity in the narrower spacing are approximately three times faster than that in the wider one. A physical mechanism primary focused on depletion width and electron-hole pairs is given to explain the above results. It is demonstrated that a straightforward way to enhance the responsivity of ZnO photodetectors for application is with different electrode spacings.

Sodium-ion batteries (SIBs) have obtained widespread attention because of the non-toxicity and low cost of element sodium. In this paper, we used first-principles methods to investigate the adsorption and diffusion of Na atom on the surface of Si3C. Calculation results show that the adsorption energy and the diffusion barrier for Na on Si3C are 2.33 and 0.26 eV, respectively, suggesting Si3C has good stability and fast charge/discharge capability as for anode in SIBs. More importantly, the Si3C can adsorb 32 Na atoms, which makes the storage capacity up to 1031 mAh/g. These advantages further suggest that Si3C monolayer could become one of the excellent candidates for anodes in SIBs.

Blue phosphorene (blue-P), an allotrope of black phosphorene, is prone to oxidize under ambient conditions, which significantly hinders its incorporation in anode for Li/Na ion batteries (LIBs/NIBs). Combining blue-P and hexagonal boron nitride (h-BN) together to construct h-BN/blue-P heterostructure (BN/P) can break the limitation of the restricted properties of blue-P. By means of first-principles computations, we explored the potential of using BN/P as anode material for LIBs/NIBs. Our computations show that the adsorption energies of Li/Na in BN/P are stronger than those in blue-P. Interestingly, although Li has similar chemical properties to Na, their the most energetically favorable sites on BN/P are different. Li prefers to insert into the interlayer of BN/P while Na prefers to absorb on the blue-P surface of BN/P. Furthermore, BN/P can achieve high theoretical specific capacities 801 and 541 mAh/g and low diffusion barriers 0.08 and 0.07 eV for LIBs and NIBs, respectively. All these characteristic...

In this work, dual-wavelength UV photodetectors were successfully constructed by growing ZnO and MgZnO layers on SiO2 substrates with ZnO/Au/MgZnO structure. The photodetectors exhibited high performance and the influence of different thickness of MgZnO layers was investigated. Moreover, simply by adjusting the applied voltage on the devices, the ratio of the two response peaks (caused by MgZnO and ZnO layers) changed therewith. The detecting properties may originate from the two layers having different increasing rates where the existence of Schottky junctions plays an important role. The photodetectors are meaningful for fabricating dual-wavelength optoelectronic devices for practical applications.

Here, we report that the co-loading of graphene quantum dots (GQDs) and PdS dual cocatalysts on ZnCdS surface achieves a high efficiency photocatalytic H2 evolution under visible light (≥420 nm). The GQDs/ZnCdS/PdS photocatalyst was prepared by a facile two steps: hydrothermal coupling of GQDs on ZnCdS surface followed by an in-situ chemical deposition of PdS. The resulted GQDs/ZnCdS/PdS exhibits a H2 evolution rate of 517 μmol h−1, which is 15, 7, and 1.7 times higher than that of pure ZnCdS, GQDs/ZnCdS, and ZnCdS/PdS, respectively, demonstrating the synergistic effects of GQDs and PdS dual cocatalysts. A high apparent quantum efficiency (AQE) up to 22.4% can be achieved over GQDs/ZnCdS/PdS at 420 nm. GQDs/ZnCdS/PdS also has a relatively good stability. Such a considerable enhancement of photocatalytic activity was attributable to the co-loading of the GQDs and PdS as respective reduction and oxidation cocatalysts, leading to an efficient charge separation and surface reactions.

In this paper, we report a highly active and robust three-dimensional (3D) Cu foam@MoSx electrode for electrocatalytic hydrogen evolution reaction (HER) prepared by a simple and controllable electrochemical deposition method. Highly conductive Cu foam scaffold with exposed 3D frameworks can not only ensure an intimate interface for facilitate a fast electron transfer but also render the deposited amorphous MoSx with abundant exposed active sites and large contact area for electrolyte diffusion. As a result, the optimized Cu foam@MoSx electrode exhibits high activity for electrocatalytic H2 evolution in 0.5 M H2SO4, the required overpotentials to reach current densities of 10 and 100 mA cm−2 are 200 and 250 mV, respectively. Moreover, the Cu foam@MoSx electrode shows no obvious deactivation after 2000 potential cycling and also retains its outstanding electrocatalytic activity after 10 h bulk electrolysis for H2 evolution due to the robust adhesion of MoSx. This work provides a new strategy to the development of highly active HER electrocatalyst by integrating high-surface-area and conductive substrate and the favorable surface structures of active components.

Efficient photocatalysts induced by visible light (e.g. BiOI) have attracted wide attention for energy storage and environmental pollutant rehabilitation. In this work, N-doped bamboo tube-like carbon (NTC) was derived directly from the carbonization of bio-waste (withered typha grass) under an ammonia atmosphere. During fabrication, the BiOI/NTC material was used as a self-sacrificing template and I- ions were gradually replaced by OH- ions from NH3·H2O solution. Then Bi7O9I3/NTC was formed with micro-/nanohierarchical structures, which could exactly be explained by the in situ ion exchange-recrystallization mechanism. Thereinto, the well-defined hierarchical lantern-like Bi7O9I3 composed of interconnecting ultrathin nanosheets firmly embedded the "bamboo tubes" of NTC, which endow sufficient interface and high specific surface area (40 m2 g-1). The multiple synergistic effects of the lantern-like structure with ultrathin nanosheets, low iodine content and well-contacted interface endow the synthesized Bi7O9I3/NTC with outstanding visible-light catalytic activity. The results show that the obtained Bi7O9I3/NTC degraded 93.5% of methyl orange and 97.6% of rhodamine B within 2 hours, showing superior performance as compared to the pure BiOI. Therefore, our work demonstrates a controllable approach that can provide guidelines for designing optimized bismuth oxyiodide-based photocatalyst materials and has the potential for application in environmental remediation.

CoAl-layered double hydroxide nanosheets (CoAl-NSs) could serve as an active matrix to effectively anchor amorphous MoSx nanoparticles with high dispersion and the formation of an additional active “CoMoS” phase. The resulting CoAl-NSs/MoSx catalyst showed 13 times higher H2 evolution activity than free MoSx nanoparticles from an erythrosin B–triethanolamine (ErB–TEOA) system under visible light.

Noble-metal-free, durable and high-efficiency electrocatalysts for oxygen reduction and evolution reaction (ORR/OER) are vital for rechargeable Zn-air batteries (ZABs). Herein, a flexible and free-standing carbon fiber membrane immobilized with atomically dispersed Fe-N4 /C catalysts (Fe/SNCFs-NH3 ) is synthesized and used as air cathode for ZABs. The intertwined carbon fibers with hierarchical nanopores facilitate the gas transportation, electrolyte infiltration and electron transfer. The larger specific surface area after NH3 activation exposes a high concentration of Fe-N4 /C sites that embedded in the carbon matrix. Modulation of local atomic configurations by sulfur doping in Fe/SNCFs-NH3 catalyst leads to excellent ORR and enhanced OER activities. As-synthesized Fe/SNCFs-NH3 catalyst demonstrates a positive half-wave potential of 0.89 V and a small Tafel slope of 70.82 mV dec-1 , outperforming the commercial Pt/C (0.86 V/94.74 mV dec-1 ) and most reported M-Nx /C (M = Fe, Co, Ni) catalysts. Experimental characterizations and theoretical calculations uncover the crucial role of S doping in regulating ORR and OER activity. The liquid-state ZABs with Fe/SNCFs-NH3 catalyst as air cathode deliver a large peak power density of 255.84 mW cm-2 and a long-term cycle durability over 1000 h. Solid-state ZAB shows stable cycling at various flat/bent/flat states, demonstrating great prospects in portable and wearable device applications. This article is protected by copyright. All rights reserved.

This study investigates the photocatalytic degradation of nitrogen oxides over graphitic carbon nitride (g-C3N4) based photocatalysts. The synthesis procedure of g-C3N4 consists of two-step: in the first step, the synthesis of g-C3N4 is carried out through a microwave heating method, whereas in the second step the as-synthesized product is annealed. The characterization was carried out by XRD (X-ray Diffraction), FESEM (Field Emission Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), BET (Brunauer-Emmet-Teller), and XPS (X-ray Photoelectron Spectroscopy). Photocatalytic activities for the degradation of NOx (Nitrogen Oxides) are compared with commercial TiO2 and g-C3N4, to investigate the structural and physio-chemical features of prepared samples and their correlation with the catalytic activity. The results show that g-C3N4 nanosheets have better activity and stability as compared to TiO2. The deposition effect of 1 wt% Pt to the g-C3N4 nanosheets is also observed which puts a negative effect on the degradation results.

Based on the interesting Janus-type all-cis1,2,3,4,5,6-hexafluorocyclohexane (1) molecule, a novel type of excess electron compounds MF-1-MH (MF = Li, Na and K, MH = Zn, Cd and Hg) were designed theoretically. The geometric structures, electronic structures and nonlinear optical properties of MF-1-MH compounds were studied by density functional theory. Our results show that in Li-1-MH, the obvious charge transfer between Li and MH can be observed while in Na/K-1-MH, the charge transfer between Na/K and MH is negligible. Particularly, the MF-1-MH exhibit remarkable nonlinear optical (NLO) response and the first hyperpolarizability of the K-1-Zn almost achieve 1.0 × 106 au. We hope this work will further enrich the family of excess electron compounds, so that more experimental interests and efforts can be attracted to propose and synthesize new excellent NLO materials.

The development of green and clean synthetic techniques to overcome energy requirements have motivated the researchers for the utilization of sustainable biomass. Driven by this desire we choose rice as starting materials source. After the explosion effect, the precursor is converted into puffed rice with a honeycomb-like structures composed of thin sheets. These honeycomb-like macrostructures, effectively prevent the cross-linking tendency towards the adjacent nanosheets during activation process. Furthermore, tuneable micro/mesoporous structures with ultrahigh specific surface areas (SBET) are successfully designed by KOH activation. The highest SBET of 3326 m2 g−1 with optimized proportion of small-mesopores is achieved at 850 °C. The rice-derived porous N-doped carbon nanosheets (NCS-850) are used as the active electrode materials for supercapacitors. It exhibites high specific capacitance specifically of 218 F g−1 at 80 A g−1 in 6 M KOH and a high-energy density of 104 Wh kg−1 (53 Wh L−1) in the ionic liquid electrolytes. These are the highest values among the reported biomass-derived carbon materials for the best of our knowledge. The present work demonstrates that the combination of “puffing effect” and common chemical activation can turn natural products such as rice into functional products with prospective applications in high-performance energy storage devices.

Lithium-rich layered oxides are widely considered as the most promising candidate for high energy density cathode in lithium-ion batteries (LIBs) due to their extraordinary capacity. However, cycle instability, poor rate capability and voltage decay impede their practical applications, which are caused by oxygen release and phase transformation during cycling. In this work, an ultrathin spinel Li4Ti5O12 (LTO) coating acting alike a “lithium ion pump” is built on the surface of lithium-rich layered oxides Li1.2Ni0.2Mn0.6O2 (LLNMO) through solvothermal method. It is identified that spinel LTO and layered LLNMO phases display heteroepitaxial structure resulting in reduction of oxygen loss, phase transformation, capacity decline and voltage fading. The cathode with heteroepitaxial structure demonstrates an acceptable initial coulombic efficiency up to 87.7% (only 79.8% for LLNMO), highly competitive cycling stability (97.9% capacity retention at 0.1C after 100 cycles), minimal voltage decay of 1.22 mV cycle−1 and excellent rate capability (171.5 mAh g−1 at 10C). The supreme electrochemical performances suggest that epitaxial spinel LTO coating can effectively stabilize oxygen framework and the layered structure on the surface of lithium-rich layered oxides for modification of high-capacity cathode in next generation LIBs.

A novel Ag-Bi2WO6-TiO2 (ABT) ternary photocatalyst was synthetized using a surface deposition and solvothermal method and its composite starch films with different amounts of ABT loading were prepared via a casting method. The morphology and microstructure of the ABT/starch composite films were characterized and their photocatalytic activity during the degradation of ethylene were evaluated. The results showed that the ABT photocatalyst exhibits excellent photocatalytic activity for the removal of ethylene under visible light with the maximum mineralization rate of 96% and CO2 production of 0.81 × 10-4. Compared with that of pure TiO2, Bi2WO6 and Bi2WO6-TiO2 composite, the reaction rate constant (k’) of ABT was improved by 188.13, 150.51, and 64.62%, respectively. When the surface loading of ABT was 2%, the photocatalytic performance of the ABT/starch film under visible-light reached its maximum with k’ increasing by 61.8% compared with the starch film without ABT loading on the surface. The improvement in the photocatalytic activity was attributed to the synergistic effect of nano-Ag, TiO2 and Bi2WO6. Ag nanoparticles are anchored on the Bi2WO6-TiO2 heterojunction, which increases the number of reactive active sites, broadens the absorption of visible light and produces more active species ·O2– and ·OH, thus enhancing the photocatalytic performance. The cooperative synergy over as-prepared ABT formed by multiple electron transfer channels composed of localized surface plasmon resonance (LSPR) enhancement, Z-sheme charge transfer and electronic sink effect results in effective charge separation and inhibits the recombination of photogenerated carriers, thus exhibiting exceptional photocatalytic activity.

We theoretically designed a novel two-dimensional (2D) donor-acceptor heterostructure, hydrogenated borophene (HB)/blue phosphorene (BP), with a very short interlayer distance (2.38 A). The molecular dynamics simulations indicate that the HB/BP heterostructure exhibits the high dynamic stability. Besides, we also explored the possibility of using HB/BP heterostructure as a potential anode for Li/Na-ion batteries (LIBs/NIBs) by performing density functional theory. Our results indicate that the HB/BP heterostructure has large adsorption energies (2.61 eV for Li and 2.17 eV for Na), low diffusion barriers (0.11 eV for Li and 0.10 eV for Na) and high storage capacities (1520 mAh/g for Li and 719 mAh/g for Na). Moreover, when the storage capacity reaches the maximum, the interlayer distances of the HB/BP heterostructure can shrink to about 2.27 A, which can buffer the anode volume change during charging/discharging of the battery. These excellent characteristics show that HB/BP heterostructure can be a new choice as anode material for LIBs/NIBs.

Low-crystalline or amorphous molybdenum sulfides (MoS x ), bearing abundant unsaturated active sites, have been identified as efficient catalysts for electrocatalytic and photocatalytic H 2 evolution reactions, however, their intrinsic activity is still low and need to be further improved for large-scale applications. In this paper, we report that low-crystalline MoS x doped with Co (Co-MoS x ) as efficient cocatalysts could be loaded on CdS nanoparticles through a facile and controllable photochemical reduction method and showed high performances in catalyzing H 2 evolution under visible light irradiation (≥420 nm). The photochemical loading of Co-MoS x was accomplished by using an in-situ formed molecular complex precursor and photogenerated electrons on CdS as reductants under mild conditions. The optimized CdS/Co-MoS x (Co:Mo = 1:4, 2 mol% loading) photocatalyst exhibited a catalytic H 2 evolution rate of 535 μmol h −1 , which is 1.8 times higher than that of CdS/MoS x , and an apparent quantum efficiency (AQE) of 23.5% was achieved over CdS/Co-MoS x photocatalyst at 420 nm. Co-MoS x catalyst also shows a long-term stability without noticeable activity degradation. Notably, Co-MoS x cocatalyst was found more efficient than that of noble metals in catalyzing photocatalytic H 2 evolution on CdS. The formation of CoMoS phase, the enhanced electrocatalytic activity as well as reduced electron transfer resistance due to the doping effects of Co ions, account for the enhanced catalytic activity of this Co-MoS x cocatalyst.

This paper demonstrates surface plasmons (SPs) enhanced MgZnO ultraviolet (UV) photodetectors grown by a radio frequency (RF) magnetron sputtering technique, and the magnesium concentration is 30%. Predominantly, well-defined Au NPs with different sizes were produced embedded in MgZnO thin films. Notably, at 30 V applied bias, the proper combination MgZnO/Au NPs (40 s), responsivity as high as 341.08 A/W is achieved after optimizing the process. Impressively, the excellent comprehensive performance of MgZnO/Au NPs UV photodetectors should have great applied potential, a physical mechanism is given to explain the above results.

Popcorn-derived porous carbon flakes have been successfully fabricated from the biomass of maize. Utilizing the “puffing effect”, the nubby maize grain turned into materials with an interconnected honeycomb-like porous structure composed of carbon flakes. The following chemical activation method enabled the as-prepared products to possess optimized porous structures for electrochemical energy-storage devices, such as multilayer flake-like structures, ultrahigh specific surface area (SBET: 3301 m2 g–1), and a high content of micropores (microporous surface area of 95%, especially the optimized sub-nanopores with the size of 0.69 nm) that can increase the specific capacitance. The as-obtained sample displayed excellent specific capacitance of 286 F g–1 at 90 A g–1 for supercapacitors. Moreover, the unique porous structure demonstrated an ideal way to improve the volumetric energy density performance. A high energy density of 103 Wh kg–1 or 53 Wh L–1 has been obtained in the case of ionic liquid electrolyte,...

Amorphous molybdenum sulfide catalysts (MoSx) can efficiently catalyze the H2 evolution reaction (HER); however, their catalytic activities are still limited that need to be improved. Herein, transition metal-promoted MoSx H2 evolution catalysts were facilely fabricated through an in-situ photochemical reduction with inexpensive organic dye as photosensitizers. Under visible light (λ ≥ 420 nm), the promotional effect of transition metals on the H2 evolution over MoSx follows the order of Co > Fe ≈ Ni > unpromoted > Cu > Zn in Erythrosin B-triethanolamine (ErB-TEOA) system. The most active Co-promoted MoSx (Co-MoSx) catalyst is amorphous and composed of inter-connected nanoparticles with diameters of 30–50 nm. The Co-MoSx catalyst contains both CoMoS phase and Co oxides/hydroxides. At the optimal reaction conditions, the Co-MoSx catalyst with Co:Mo ratio of 4:6 exhibits enhanced H2 evolution activity by 2 times as compared to unpromoted MoSx and turnover numbers (TONs) of 30 and 60 based on ErB and catalyst used, respectively. The Co-MoSx catalyst also shows a long-term stability without noticeable activity degradation. The formation pathways of Co-MoSx catalyst and the photocatalytic mechanism for enhanced H2 evolution performance were studied and a two-step reaction mechanism involved an oxidative quenching pathway of dye was proposed. This study demonstrates that in-situ concurrent photochemical fabrication with transition metal modification of amorphous MoSx catalyst is an effective strategy for development of MoSx-based HER catalysts with enhanced performances.

The coupling of semiconductor photocatalysts with graphene quantum dots (GQDs) has been proven to be an effective strategy to enhance the photocatalytic and photoelectrical conversion performances of the resulted composites; however, the preparation of semiconductor/GQDs composites usually involves several time-inefficient and tedious post-treatment steps. Herein, we present a facile one-step hydrothermal route for the preparation of GQDs coupled TiO2 (TiO2/GQDs) photocatalysts using 1,3,6-trinitropyrene (TNP) as the sole precursor of GQDs. During the hydrothermal process, TNP molecules undergo an intramolecular fusion to form GQDs, which simultaneously decorate on the surface of TiO2 nanoparticles, leading to a strong surface interaction between the two components. The effective coupling of GQDs on TiO2 can effectively extend the light absorption of the TiO2 to visible region and enhance the charge separation efficiency of TiO2/GQDs composites as a result of GQDs acting as a photosensitizer and an excellent electron acceptor. These key advances make the TiO2/GQDs photocatalyst highly active towards the H2 evolution reaction, resulting in 7 and 3 times higher H2 evolution rate and photocurrent response at optimal GQDs content than TiO2 alone, respectively. This study provides a new methodology for the development of high-performance GQDs modified semiconductor photocatalysts for energy conversion applications.

In this work, cobalt micro-particles containing various nanoscale subunits were hydro- thermally synthesized and controlled by the content of sodium tartrate in reaction solution. Both the static and dynamic magnetization properties of cobalt particles changes accordingly. As the content of sodium tartrate varies from 0 g, 0.552 g to 4.416 g, subunits of the cobalt particles shrinks from dendrites, coralloids to small bumps, saturation magnetization changes from 122.5 emu/g, 86.5 emu/g, to 95.79 emu/g, and the coercive force reduces from 195 Oe, 148 Oe, to 62 Oe. Consequently, ferromagnetic resonance bandwidth of the cobalt particles decreases due to the diminishing surface scatterers (subunits), whereas low frequency loss tangential increases following the growth of spherical particle core. The proposed cobalt particles with nanoscale subunits shows potential for electromagnetic wave absorption and shielding application.

We report on metal-semiconductor-metal ultraviolet photodetectors based on a ZnO film/Pt nanoparticles/ZnO film composite structure. The responsivity of the sandwich photodetector is 45 times greater for the back-illuminated than the front-illuminated. Surprisingly, the responsivity of a ZnO photodetector without the Pt nanoparticles has rather feeble enhancement under the same conditions (illumination from back and front). The responsivity of the sandwich photodetector can be enhanced from 14 to 45 times by adjusting the embedded depth of the Pt nanoparticles. Combining this result with the optical absorption spectra of ZnO films with and without Pt nanoparticles, we can reasonable to deduce the underlying mechanism and attribute it to the coupling of the localized surface plasmon from Pt nanoparticles with ZnO films. These results demonstrate a method to control the responsivity enhancement by adjusting the embedded depth of the Pt nanoparticles in the sandwich photodetector.

The purpose of this study is to develop an active, low cost, non-precious, stable, and high-performance catalyst for oxygen reduction reaction (ORR). In this regard, Mn2O3-decorated nitrogen-doped carbon nanosheets (Mn2O3/NC) are fabricated by a two-step strategy involving a hydrothermal method and a solid-state method. In the resultant structures, very fine Mn2O3 nanoparticles with an average size of about 5 nm are strongly attached to nitrogen-doped carbon nanosheets. The role of the Mn2O3 nanoparticles is to provide active sites for ORR, while the presence of the nitrogen-doped carbon not only enhances the conductivity of the overall structure but is also helpful for overall stability. The Mn2O3/NC shows good onset potential (0.80 V@−1 mA/cm2), methanol crossover effect, and stability (90%).

Sodium (Na)-ion batteries (NIBs) and potassium (K)-ion batteries (KIBs) have grabbed great attention because they are cheaper, more abundant in earth, and safer alternatives of lithium-ion batteries. However, the lack of anode materials for NIBs/KIBs with good performance has been the main obstacle. In this paper, we studied monolayer MnC by carrying out calculations on the basis of first principle study to see if it can be a potential anode material for NIBs and KIBs. Calculation results show that monolayer MnC processes good negative adsorption energies of - 2.83 eV for Na and - 2.16 eV for K. Moreover, MnC has comparable theoretical capacities for Na and K of 475 mAh/g and 253 mAh/g, respectively. Our calculation results manifest that the MnC can be a promising anode material for NIBs. MnC monolayer absorbed with two layers of Na atoms.

Bismuth oxyiodide (BiOI) is among the most potential photocatalysts due to its photocatalytic activity under visible light irradiation. However, the photoinduced carrier separation efficiency has limited the BiOI photocatalytic activity. Herein, we utilized the direct carbonation of sapless cattail grass to obtain N-doped hierarchical structure cattail-based carbon (NCC). The NCC not only served as an appropriate host but also as a self-sacrificing template for BiOI microspheres for the preparation of BiOI/NCC composite material. The acidic solutions (HCl or AcOH) were used as a solvent which helped to obtain a well-defined micro/nano hierarchical BiOI microspheres composed of ultrathin nanosheets. Thus, BiOI/NCC composites were successfully designed through the in-situ self-template rapid dissolution-recrystallization mechanism. Additionally, numerous well-contacted interfaces were formed between NCC and BiOI, which served as an electron-acceptor bridge function for ultrafast electron transfer process in order to hinder the electron-hole pairs recombination. On account of the multiple synergistic effects of micro/nano hierarchical microsphere structure, ultrathin nanosheets, and well-contacted interface, the as-prepared BiOI/NCC composites exhibit the superior degradation of rhodamine B (RhB) than pure BiOI under visible light irradiation.

With the aid of ab initio calculations at the MP2 level of theory, a novel type of alkaline-earthides, namely Li(NH3)4M (M = Be, Mg, Ca), has been theoretically designed and investigated. These compounds possess a similar geometric structure, in which the alkali-metal cation Li+ lies near the center of the cagelike (NH3)4 complexant and the alkaline-earth anion M− is located outside. All the proposed alkaline-earthides exhibit extremely large static first hyperpolarizability (β0) up to 8.01 × 106 au, indicating that they can be considered as novel NLO molecules with high performance. The calculated results reveal that the alkaline-earth atom is more suitable to serve as excess electron acceptor in excess electron compounds for increasing the β0 value. We hope that our study can attract more research interest in alkaline-earthides and further experimental research.

Ideal anchoring materials can inhibit the shuttle effect which is one of the major challenging issues in lithium-sulfur (Li-S) batteries. Here, we employ first-principle calculations to systematically investigate the potential application of FeS monolayer as anchoring material for Li-S batteries. Our calculations show that the adsorption energies of Li2Sn (n = 1, 2, 4, 6 and 8) and S8 over FeS monolayer are moderately strong, about in the range 1.00 – 3.26 eV. Further analysis of the adsorption energy reveals that the van der Waals physical adsorptions mainly contribute to anchoring S8 and Li2Sn (n = 8, 6, 4 and 2) while the chemical interaction mainly contribute to anchoring Li2S. Moreover, the ultra-small energy barrier for Li2S diffusion over FeS monolayer will make Li2S transfer ultrafast, thereby restraining the agglomeration of Li2S and improving reaction rates. Our results demonstrate that the FeS monolayer may act as an excellent anchoring material for high-efficiency Li-S batteries.

Two-dimensional (2D) graphene-like hexagonal borophene sheet (HBS) is a kinetically unstable configuration since the electrons of π-valence orbitals of HBS are less than those of graphene. Inspired by the planar hexacoordinate wheel-type Fe©B6H6, we theoretically designed a novel 2D material FeB6 where the HBS can be stabilized by Fe atoms located at the center of partial boron rings. Moreover, we also investigated the possibility of using FeB6 monolayer as a potential anode for Li-ion batteries (LIBs) and Na-ion batteries (NIBs). Our calculations showed that FeB6 monolayer had strong adsorption energies (2.89 eV for Li and 2.39 eV for Na), low diffusion barriers (0.24 eV for Li and 0.10 eV for Na) and high theoretical specific capacities (991 mAh/g for Li and 622 mAh/g for Na), which indicates that FeB6 monolayer can be a potential anode material for LIBs/NIBs.

A novel 2D bonding heterostructure consisting of hexagonal borophene monolayer bonding with two blue phosphorene layers was designed theoretically, which possesses high stability, good conductivity and high in-plane stiffness. Subsequently, the heterostructure as an anchor material for lithium-sulfur (Li-S) batteries was investigated systematically by using density functional theory. Our results indicate that lithium polysulfides on the heterostructure have appropriate adsorption energies (0.60–2.68 eV) and moderate diffusion barriers (0.09–0.31 eV), which can suppress the “shuttle effect” and inhibit the agglomeration of lithium polysulfides. Therefore, the novel heterostructure can hold great promise as an anchoring material for Li-S batteries.

It remains a challenge to improve the photocatalytic activity of bismuth oxychloride (BiOCl) under visible light irradiation. In this work, BiOCl was changed by doping iron ions with a simple chemical precipitation method. During fabrication, under acidic conditions (pH = 3), bismuth nitrate and ferric chloride were mixed together and then annealed at 400 ℃, 450 ℃, 500 ℃ and 550 ℃, respectively. Finally, Bi0.7Fe0.3OCl with uniform doping of Fe (III) was obtained. The properties of Bi0.7Fe0.3OCl samples were characterized by XRD, SEM, TEM, XPS, and UV–vis. Bi0.7Fe0.3OCl nanomaterials synthesized at different temperatures were compared for their photocatalytic performance through investigating the degradation of a dye (Rhodamine B) under visible light. The experimental results showed that doping with Fe (III) can improve the visible light catalytic efficiency of BiOCl. Bi0.7Fe0.3OCl-450 had the best RhB removal rate, reaching 74 % within 3 h, which was about 4.8 times higher than pure BiOCl. This work may provide a promising method for preparing metal-doped BiOCl materials with efficient photocatalytic performance by generating large quantities of electron-holes during the photoreaction process.

Owing to the potential to solve environmental issues, semiconductor photocatalysis process using solar energy has drawn significant attention in recent decades. So, the photocatalysis major issues have solved by semiconductor nanotechnology. Here, BiOBr layered structures are synthesized with induced IEF, oxygen vacancies, and layer growth along {001} direction by using hydrothermal synthesis method. Therefore, we exercise optimized amounts of EG, which organized Bi ions at the surface of BiOBr. The exposed {001} facet orientation and oxygen vacancy generation are controlled by using EG. Consequently, the bonding force of the Bi-O band is reduced, allowing O atoms to be dragged out under solar light irradiation, resulting oxygen vacancies produced. Finally, these oxygen vacancies induced IEF across the layers of BiOBr, which suppressed electrons-holes recombination and enhanced reaction process with the degraded material achieved. Most significantly, optimized EG quantity has used to the synthesis of BiOBr structures, which improve photogenerated electrons holes (e−-h+) pairs capability due to IEF and oxygen vacancies. Thus, an optimized quantity of EG is a strategic measure to induce IEF, which is significant for separation of (e−-h+) pairs, consequently, it enhances photocatalytic performance and has considered a novel method.

Well-controlled brush-shaped block copolymers (BBCPs) of high molecular weight with polystyrene (PS) and polylactic (PLA) side chains, (poly (cis-5-norbornene-exo-2,3-dicarboximide-end poly (styrene)))-block-(poly (cis-5-norbornene-exo-2,3-dicarboximide-end poly (lactide))) (PNB-g-PS)-b-(PNB-g-PLA) were synthesized by combining atom transfer radical polymerization (ATRP) and ring opening polymerization (ROP). The synthesis of the (PNB-g-PS)-b-(PNB-g-PLA) was well-controlled with molecular weight and polydispersity index (Mn, GPC = 1310000 g mol-1 and Mw/Mn (GPC) = 1.16). The SEM, XRD and DSC reveal that there are two immiscible cis-5-norbornene-exo-2,3-dicarboximide-end poly(styrene) (NB-PS) and cis-5-norbornene-exo-2,3-dicarboximide-end poly(lactide) (NB-PLA) phases in BBCP after self-assembly, which leads to partial crystallization. Moreover, the effect of the self-assembly temperature on morphology and reflectance of (PNB-g-PS)-b-(PNB-g-PLA) has been investigated. These (PNB-g-PS)-b-(PNB-g-PLA) exhibit obvious pearlescent appearance and wide band reflection after heat-treated at different temperatures (120 °C, 130 °C, 140 °C and 150 °C). Besides, with the increase of the self-assembly temperature, the domain spacing of (PNB-g-PS)-b-(PNB-g-PLA) decreases and the reflectance in visible range of (PNB-g-PS)-b-(PNB-g-PLA) increases. However, the self-assembly temperature does not significantly influence the reflection wavelength range of (PNB-g-PS)-b-(PNB-g-PLA).

To reduce capacity attenuation during cycling and improve ultrahigh-sulfur-loading of Li-S batteries, we have manufactured nitrogen doped hollow carbon nanospheres (60 nm) with interconnected mesoporous shell (MHCS) as conducting frameworks for sulfur loading. One-step dual template technique is employed to prepare nitrogen doped polymer-silica nanocomposites with “interpenetration twins” nano-architectures at the initial stage. After carbonization and etching of silica, the “interpenetration twins” nano-architectures converted into interconnected functionalized mesoporous carbon nanospheres that endow desired micro-mesoporous volume (4.75 cm3/g) and high-specific area (SBET, 1875 m2/g). To the best of our knowledge, we achieved the highest sulfur content (90.4 wt%) in the carbon-based cathodes due to the interlinked pore network between S and carbon skeleton, which is formed by occupying the space of the removed silica with sulfur. In this way sulfur element could be closely contacted with the conductive carbon skeleton. Furthermore, polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) composite polymer were adhesive on the encapsulated carbon shell to limit the leakage of lithium sulfide leading to an improved the capacity retention of Li-S batteries. Noticeably, the average of the capacity decay reached to 0.023% per cycle during 3,100 cycles, which represent optimal performance of long-period lithium-sulfur batteries heretofore. The effortless method can provide a new way to design exceptionally high pore volume with interconnected mesoporous, and maintained definite hollow nanostructure, which are critical for porous carbons and energy storage.

Nb2O5 appeared as a promising candidate for a large number of applications. In the present work novel, 3D-hollow hierarchical Nb2O5 superstructures are prepared by self-organization of mesorods. The work emphasizes on the synthesis and detailed investigation of 3D-hollow hierarchical Nb2O5 superstructures, which are attained by two-step, template-free hydrothermal synthesis route. The obtained orthorhombic(T)-Nb2O5 superstructures have shown a high crystallinity, with a wide band gap of 3.1 eV. Among semiconductor oxides Nb2O5 with different morphologies are less explored due to complicated synthesis, growth and nucleation process. Thus, in general, factors involved for self-organized superstructures are not studied in detail. In this context, assembly of T-Nb2O5 superstructures is investigated in depth by applying SEM, TEM and UV/Vis absorption measurements. Based on the realized results a formation mechanism is proposed, which is further strengthened by the time and precursor dependent experiments. In addition, asymmetric supercapacitor properties of T-Nb2O5 superstructures are studied for the first time by using an inorganic electrolyte. The devised T-Nb2O5 superstructures have demonstrated excellent supercapacitor performance. The supercapacitor is operated at a wide potential window of 2.5 V in Na2SO4 electrolyte and exhibited high power density (650 W/Kg), energy density (86 Wh/Kg) with good cycling capability.

By means of first-principles computations, we explored the potential of using Y2C monolayer as anode material for rechargeable Na-ion batteries (NIBs). As a two-dimensional electride material, Y2C monolayer is metallic and has a strong in-plane stiffness. Significant interactions between Y2C monolayer and Na atom ensure its high theoretical specific capacity of 564 mA·h/g. The Y2C monolayer also has high Na mobility and rather small average open-circuit voltages. All these characteristics suggest that the Y2C monolayer could be a promising anode material for NIBs.

A series of ultraviolet photodetectors have been fabricated on MgZnO films, the molar ratio of Mg/Zn is about 18%, which grown by a radio frequency magnetron sputtering technique. Metal (Pt) nanoparticles are sputtered on the surface of the MgZnO film, embedded into the film and deposited on the substrate to improve the performances of the photodetectors, respectively. I–V characteristics under dark are improved by sputtering Pt nanoparticles on the surface of MgZnO film. Meanwhile, the photoresponse of the photodetectors with Pt nanoparticles are enhanced, especially when nanoparticles embedded into the MgZnO film, the peak responsivity is enhanced from 0.134 to 0.349 A/W at 30 V bias. It is demonstrated that the key role of Pt nanoparticles in the performance enhancement of MgZnO-based photodetectors, revealing the applicability of metal nanoparticles in ultraviolet photodetectors.

The structure and electrochemical storage characteristics of the Ti 1.4 V 0.6 Ni + xZrH 2 (x = 5, 10 and 15 wt.%) mixture powders, which synthesized by melt-spinning technique and subsequent mechanical ball-milling, are studied at ambient temperature. The XRD shows that the Ti 1.4 V 0.6 Ni alloy contains icosahedral quasicrystal phase (I-phase), V-based solid solution phase with BCC structure and face centered cubic (FCC) phase with Ti 2 Ni-type structure. After adding ZrH 2 , we find that NiZr phase and ZrH 2 phase presence in the XRD of composite materials. In the equation, x is equal to 10 wt.%, and 317.5 mAh/g is the maximum discharge capacity at the first cycle. For another, the materials without the ZrH 2 are pale when they compare with the composite materials which contain the ZrH 2 in high-rate dischargeability (HRD) and cycle stability.