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CoSe 2 has become one of the most appealing non-noble metal catalysts for hydrogen evolution reaction (HER) in the field of electrolysis water due to its abundant resources and good activity. Inversely, its slow kinetic behavior is still restrained, which plays a negative influence for high-efficiency HER. Herein, a certain of Ni or S was introduced into the (100) crystal facet of CoSe 2 on the basis of density functional theory (DFT) calculations. Thermodynamic calculation results reveal that the HER activity for CoSe 1 S 1 is relatively better than those of Ni 0.375 Co 0.625 Se 2 and pristine CoSe 2 when a certain of S atoms were introduced into CoSe 2. More strikingly, the active sites of CoSe 1 S 1 are reversed from cationic Co to anion S, which is close to the ideal value (0) of Gibbs free energy. Meanwhile, the kinetic performance of H adsorbed on the anionic S or Se site is optimal, and their migration energy barrier is lower in comparison with 1/2 of the cationic Co site. According to the electronic structure analysis, the conductivity of CoSe 1 S 1 is prominent than other counterparts (such as Ni 0.375 Co 0.625 Se 2 and CoSe 2). This work indicates that CoSe 1 S 1 exhibits an excellent catalytic performance for HER, and offers theoretical guidance in the aspect of experiments for designing high-efficient HER catalysts. [Display omitted] • The doping of S into Se sites of CoSe 2 was systematically investigated. • The CoSe 1 S 1 presented more active sites and high conductivity. • The S sites in CoSe 1 S 1 are thermodynamically beneficial for HER catalysis. • The kinetic rate of S sites is superior to that of Co within CoSe 1 S 1. [ABSTRACT FROM AUTHOR]

Three-dimensional hierarchical SnO 2 microspheres were successfully synthesized through a rapid sonochemical reaction followed by a facile solvothermal process. The resultant samples were characterized in detail by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM). It was observed that the hierarchical SnO 2 microspheres (∼2.2 μm) consist of nanoparticles (∼23–30 nm). These samples are used to fabricate photoelectrodes for dye-sensitized solar cells (DSSCs). The effects of different samples on the photovoltaic performance were studied based on photocurrent-voltage ( J – V ), intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated voltage spectroscopy (IMVS). It is found that the highest power conversion efficiency of 6.25% has been achieved based on the hierarchical SnO 2 microspheres film photoanode with thickness of ∼13.5 μm, and the corresponding photovoltaic parameters are 14.11 mA cm −2 in short-circuit current density, 803 mV in open-circuit voltage and 0.55 in fill factor, respectively. [ABSTRACT FROM AUTHOR]

A one‐step approach of synthesis and interfacial functionalization of Mo to modify TiO2 nanocrystallines (iMTNCs) derived from tetrabutyl orthotitanate is proposed through mild alkaline and reductive hydrothermal reaction. Ultrafine crystallite sized TiO2 nanocrystallines (TNCs) with functionalized interface are obtained from the interfered synthesis process by hydrothermal etching and liquid phase infiltration of Mo dopants. The composite iMTNCs−C (incorporated with carbon black) is employed as the functionalized support for PtRu binary catalyst towards methanol electrooxidation. The resultant PtRu/iMTNCs−C catalyst manifests 1.68 times higher mass activity comparing to that of the un‐functionalized catalyst (PtRu/TNCs−C) and 1.44 times enhanced mass activity to PtRu/C catalyst with improved durability. These improvements in catalytic performance are attributed to the electronic donation from Mo functionalized interface of iMTNCs to PtRu nanoparticles (NPs) and ultrafine crystallite sized architecture of composite support. This work suggests a potential application of the functionalized nanocrystalline support material in fuel cell. [ABSTRACT FROM AUTHOR]

A synchronous carbon‐coating and interfacial‐functionalizing approach is proposed for the fabrication of Mo‐doped MoxTi1−xO2‐δ nanotubes (C@IF‐MTNTs) under mild hydrothermal reaction with subsequent annealing as advanced catalyst supports for PtRu nanoparticles (NPs) towards methanol electrooxidation. The carbonation of glucose and Mo‐doping takes place simultaneously at the interface of pristine anatase TiO2 nanotubes (TNTs), generating a unique concentric multilayered one‐dimensional (1D) structure with crystalline an anatase/rutile mixed‐phase TiO2 core and Mo‐functionalized interface and subsequently a carbon shell. The obtained PtRu/C@IF‐MTNTs catalyst exhibits an over 2 times higher mass activity with comparable durability than that of the unmodified PtRu/C@TNTs catalyst and over 1.7 times higher mass activity with over 20 % higher stability than that of PtRu/C catalyst. Such superior catalytic performance towards methanol electrooxidation is ascribed to the Mo‐functionalized interface, concentric multilayered 1D architecture, and anatase/rutile mixed‐phase core, which facilitates the charge transport through 1D structural support and electronic interaction between C@IF‐MTNTs and ultrafine PtRu NPs. This work reveals the critical application of a 1D interfacial functionalized architecture for advanced energy storage and conversion. [ABSTRACT FROM AUTHOR]

Electrostatically assembled ultrathin rhodium nanosheet–gold nanowire nanocomposites (Rh–Au CNSs) were used as an advanced electrocatalyst for the methanol oxidation reaction, which revealed a mass activity of 355 mA mgRh−1 at 0.607 V potential, much higher than single metal Rh nanosheets (273 mA mgRh−1) and commercial Rh nanoparticles (165 mA mgRh−1). [ABSTRACT FROM AUTHOR]

A facile and efficient hydrolysis process was proposed to create graphene nanosheets-SnO 2 nanocomposites (GSCS). The hydrolysis reaction results in the formation of pure phase SnO 2 nanoparticle (∼10 nm in size) uniformly dispersed on graphene sheets while simultaneously cause reduction of graphene oxide. The as-prepared materials were characterized in detail by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Raman spectra and X-ray photoelectron spectroscopy (XPS). In the investigation of photocurrent response properties, it was found that the photocurrent of GSCS was 130 μA/cm 2 , which is about 4 times higher than that of SnO 2 . [ABSTRACT FROM AUTHOR]

The engineered interfacial and configuration design of anode materials plays pivotal role in photovoltaic performance of solar cells. Here we demonstrated a double layered SnO 2 @TiO 2 -ZnO nanoplates composite films on fluorine-doped tin oxide (FTO) substrate as photoanodes for high-performance dye-sensitized solar-cells (DSSCs). The results indicate that DSSCs based on double layered SnO 2 @TiO 2 -ZnO nanoplates composite film (∼5.55%) show an obvious 29.1% increase of power conversion efficiency as compared to the single layered SnO 2 @TiO 2 nanoparticles photoelectrode with the same thickness of ∼18.5 μm. Intensity-modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) as well as electrochemical impedance spectra (EIS) measurements show that the double layered SnO 2 @TiO 2 -ZnO nanoplates film has faster electron transport rate and slower electron recombination rate than the SnO 2 @TiO 2 one. Furthermore, final power conversion efficiency has been optimized to reach up ∼6.37% ( J sc of 17.18 mA cm −2 , V oc of 742 mV and FF of 0.50) for the double layered SnO 2 @TiO 2 -ZnO nanoplates film photoanodes with the introduction of additional SnO 2 blocking layer which would suppress the electron recombination between FTO glass and electrolyte. One of the specific advantages of the unique structure is the engineered integration of different promising materials, which made it possible to take full advantages of the superior dye adsorption, charge collection, charge transfer dynamics as well as optical scattering simultaneously. This study provides a scheme to selective combination of specific semiconductors metal oxides, namely, SnO 2 , TiO 2 and ZnO, into an ideal photoanode configuration according to the feasible electron injection and transport dynamics, which has been regarded as promising photoanode materials for DSSCs. Fundamentally, this unique structure not only enables the high-efficiency solar cells application, but also provides a scheme for the inspiration of materials integration and guidance of effective materials surface and interfacial modification. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR) in a cathode is an essential component of many electrochemical energy storage and conversion systems. Two‐dimensional materials are beneficial for electron conduction and mass transport with high density, showing prominent electrochemical catalytic performance towards the ORR. Herein, a simple NaCl‐assisted method to synthesize cobalt–nitrogen‐doped carbon materials (CoNC), which present prominent performance towards the ORR in alkaline media, is described. The utilization of the NaCl template endows the product with a large specific surface area of 556.4 m2 g−1, as well as good dispersion of cobalt nanoparticles. CoNC‐800@NaCl (800 indicates the calcination temperature in °C) displays an excellent onset potential of 0.94 V (vs. a reversible hydrogen electrode), which is close to that of commercial Pt/C. Additionally, CoNC‐800@NaCl also exhibits better long‐term durability and methanol tolerance than that of Pt/C. The high‐performance CoNC‐800@NaCl catalyst provides a hopeful alternative to noble‐metal catalysts for the ORR in practical applications. Sprinkle of salt: Two‐dimensional cobalt–nitrogen‐doped carbon nanosheets were successfully fabricated through a simple sodium chloride assisted pyrolysis method (see figure). These nanosheets have been tested as electrocatalysts for the oxygen reduction reaction. [ABSTRACT FROM AUTHOR]

Abstract Lithium-ion batteries (LIBs) are considered as a promising power source for electric vehicles and electronic products such as mobile phones, laptops, and tablets. The anode material plays a crucial role in the reliability and safety of LIBs. Among the anode candidates, MLi 2 Ti 6 O 14 (M = 2Na, Sr, Ba, Pb) materials have very good prospects due to their excellent safety, good structure stability, negligible volume change, and suitable voltage plateau of about 1.3–1.4 V (vs. Li0/Li+). However, MLi 2 Ti 6 O 14 materials frequently sustain serious capacity decay at high rate due to the poor electronic and ionic conductivities. Therefore, it is very meaningful to summarize comprehensively and scientifically the advances of this material family from all aspects. The main objective of the review is aimed to summarize various proposed strategies (i.e. material treatment, morphology control, surface modification, and cation doping) and the breakthroughs to enhance the rate capacity and cycling stability of the MLi 2 Ti 6 O 14 materials. The review will provide some insights into the structures and performance issues, which will be helpful for the design and optimization of the MLi 2 Ti 6 O 14 materials. Highlights • Progress of MLi 2 Ti 6 O 14 is summarized in details for the first time. • An understanding on modifying MLi 2 Ti 6 O 14 from various aspects is summarized. • Key strategies for improving the cycling stability of MLi 2 Ti 6 O 14 is discussed. • Strategies in the development of MLi 2 Ti 6 O 14 -based batteries are discussed. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Three-dimensional hierarchical SnO 2 microspheres (∼0.35–1.60 μm) comprised of 5–10 nm SnO 2 nanoparticles are successfully obtained through a facile hydrothermal reaction pathway, which are detailly characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and Transmission electron microscopy (TEM). These samples are then used in photoanodes in dye-sensitized solar cells (DSSCs), whose photovoltaic performances are discussed with photocurrent-voltage ( J-V ) curve. And the highest power conversion efficiency of 4.21% is achieved as the result of hierarchical SnO 2 microspheres (200 °C 12 h) film (∼15.9 μm in thick) photoanode, and the corresponding short-circuit current density ( J sc ) is 9.38 mA cm −2 , open-circuit voltage ( V oc ) is 692 mV, and the fill factor (FF) is 0.59, respectively. Based on the time-dependent SnO 2 products, we propose the evolution mechanism of SnO 2 microspheres. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) have attracted lots of significant interests, arising from in regard to the development of developing a low-cost energy storage system for renewable energy. Antimony-based materials with that have high theoretical storage capacities of Na + have become one of the most focused SIB anode materials. Among of which, Sb 2 O 4 has a higher and thus superior Na + storage capacity of 1227 mAh g −1 compared to other antinomy-based materials. In this work, one simple solvothermal process has been developed to prepare Sb 2 O 4 /reduced graphene oxide (Sb 2 O 4 /RGO) composites with a nanostructure of Sb 2 O 4 nanorods anchored on RGO. Sb 2 O 4 /RGO shows an obviously enhanced electrochemical performance with an initial Na + storage capacity of 842 ± 5 mAh g −1 , a rechargeable capacity of 551 ± 5 mAh g −1 at 50 mA g −1 after 100 cycles and an excellent rate performance of 401 ± 5 mAh g −1 at 1 A g −1 . [ABSTRACT FROM AUTHOR]

Hybrid materials of CoFeO nanoparticles anchored on graphene prepared by a facile hydrothermal process was developed to be anode material for sodium-ion battery. The hybrid nano-structure of CoFeO/graphene not only could be useful to buffer electrode volume accompanying with Na insertion-extraction, but also could be beneficial to improve electrode electric conductivity and further keep graphene sheet separated to improve ion diffusion rate. Electrochemical measurements showed that the hybrid material anode displayed an excellent performance with a large reversible capacity of 330 mAh g after 75 cycle times and a satisfactory rate capability of 170 mAh g at 1 A g. [ABSTRACT FROM AUTHOR]

The small-size SnO 2 particles uniformly dispersed on the nitrogen doping graphene nanocomposites (SnO 2 -N-GNS) have been successfully synthesized by a mild hydrothermal method with the precursors of graphene oxide, urea and SnCl 4 . 5H 2 O. The phase (XRD, EDX and XPS) and morphology (SEM, TEM) analysis further confirm the obtained products. When the composite served as anode material in sodium ion batteries (SIBs), it delivers superior sodium storage performance with reversible discharge capacity of 294.4 mAh g −1 at a current density of 50 mA g −1 in the voltage range from 0.01–3 V after 50 discharge/charge cycles, which is much higher than that of SnO 2 -GNS (182.9 mAh g −1 ) and N-GNS (114.9 mAh g −1 ). Besides, the SnO 2 -N-GNS electrode also exhibits admirable rate stability with the discharge capacity of 206 mAh g −1 even at 800 mA g −1 . More importantly, the SnO 2 -N-GNS shows lower internal resistance and larger sodium-ion diffusion coefficient. These enhanced electrochemical performances of SnO 2 -N-GNS are due to the N-doping defects and the homogeneous dispersion of SnO 2 particles. [ABSTRACT FROM AUTHOR]

Nanocomposites of porous graphene anchored with Sb/SbO x nanoparticles were synthesized through a two-step wet chemical process. SbO x /graphene was initially prepared by refluxing SbCl 3 and graphene oxide in benzyl alcohol. Subsequently, the SbO x nanoparticles were partially reduced by NaBH 4 . The nanocomposites exhibited an enhanced performance for sodium-ion battery with a stable sodium-ion storage capacity of 311.6 mAh g −1 at 50 mA g −1 after 100 cycles and a rate capability of 205.6 mAh g −1 at 800 mA g −1 . Reduction of SbO x by adding moderate amount of NaBH 4 was conducive in improving the nanocomposite's electrochemical performance. The sodium-ion storage capacity of Sb/SbO x /graphene material was 1.4 times higher than that of SbO x /graphene without NaBH 4 and 6.2 times higher than that of Sb/graphene with excessive amount of NaBH 4 . [ABSTRACT FROM AUTHOR]

Graphene-titanium dioxide (TiO 2 ) materials were prepared using titanium tetrachloride (TiCl 4 ) and graphite oxides (GO) via a simple and continuous vapor reaction process. TiO 2 nanoparticles obtained from the reaction assembled into clusters loading on graphene or attached onto graphene individually to form graphene-TiO 2 nanocomposites. Graphene not only could enhance the nanocomposite electric conductivity but also is useful to improve the material porosity. The nanocomposites exhibited an enhanced performance for Na-ion battery anode with a specific capacity of 115 mAhg −1 at a current of 1 A/g and a stable specific capacity of 102 mAhg −1 at 0.1 A/g after 300 cycles. [ABSTRACT FROM AUTHOR]

Nanosize N-doped graphene is prepared from N-containing carbon nanotubes (CNTs) by chemical exfoliation. The CNTs adopted for graphene are characterized by a discontinuous wall that consists of nanosize graphite layers, exhibiting a bamboo-like appearance. Take advantage of this characterization, the most time-consuming process of chemical oxidation that involves intercalation in graphene from CNT has been markedly reduced. The reduction in processing time is attributed to the diffusion distance of chemical oxidation intercalation into nanosize graphite composed of a bamboo-like carbon nanotube (BCNT) wall being far less than that of conventional chemical exfoliation into microsize graphite. The as-prepared nanosize N-doped graphene from BCNTs has shown an excellent electrochemical performance for Li-ion battery and Na-ion battery anode materials. [ABSTRACT FROM AUTHOR]

An easy yet viable hydrothermal reaction is demonstrated to prepare ultra-small Zn 2 SnO 4 nanoparticle with ~4.2 nm decorated reduced graphene oxide (RGO) nanocomposites (Zn 2 SnO 4 -RGO). The pure phase Zn 2 SnO 4 nanoparticles with ~4.2 nm can be achieved during hydrothermal reaction, meanwhile, these nanoparticles uniformly dispersed on 2D graphene sheet, and graphene oxide was reduced. The photocatalytic performances of the as-prepared Zn 2 SnO 4 -RGO nanocomposites with different RGO mass ratio are investigated. The optimum synergetic effect is found when the RGO mass ratio is 7.11%, with the photocurrent and photodegradation efficiency improved by about 300% and 80% on methylene blue (MB), respectively, compared with the pure Zn 2 SnO 4 nanoparticles. Image 1 • Nano-Zn 2 SnO 4 /Reduced Graphene Oxide Composites were successfully fabricated via an easy yet viable hydrothermal reaction. • The optimum synergetic effect is found at a RGO mass ratio of 7.11%. • The photocurrent response and photodegradation efficiency of Zn 2 SnO 4 -RGO composites were superior to that of pure Zn 2 SnO 4. • The photoelectric and photocatalytic properties of Zn 2 SnO 4 -RGO composites with different amounts of RGO were investigated. [ABSTRACT FROM AUTHOR]

Low hydrophilicity of graphene is one of the major obstacles for biomaterials application. To create some hydrophilic groups on graphene is addressed this issue. Herein, COOH+ ion implantation modified graphene (COOH+/graphene) and COOH functionalized graphene were designed by physical ion implantation and chemical methods, respectively. The structure and surface properties of COOH+/graphene and COOH functionalized graphene were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle measurement. Compared with graphene, COOH+/graphene and COOH functionalized graphene revealed improvement of cytocompatibility, including in vitro cell viability and morphology. More importantly, COOH+/graphene exhibited better improvement effects than functionalized graphene. For instance, COOH+/graphene with 1 × 1018 ions/cm2 showed the best cell-viability, proliferation and stretching. This study demonstrated that ion implantation can better improve the cytocompatibility of the graphene. [ABSTRACT FROM AUTHOR]