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(a∼b): Morphologies of large-area uniform sapphire-based Ag/Au hybrid coupled nanoarrays (SA-Ag/Au HCNAs) with low (a) and high (b) magnifications. c: The plasmonic photocatalysis for PNTP based on SA-Ag/Au HCNAs substrate. d: Raman mapping characterization results at the 1162 cm-1 position of CV molecule with a scanning accuracy of 0.02 mm over 1 mm * 1 mm. [Display omitted] • Sapphire-based Ag/Au hybrid coupled nanoarrays with high SERS activity and plasmonic photocatalytic properties were obtained. • "Droplet funnel" method was employed for large-area uniform assembly of Au nanoparticles. • The prepared substrates showed excellent photocatalytic properties for PNTP molecules. • The synergistic electromagnetic enhancement effect of Ag-Au hybrid coupling is 26.661 times higher than that of pure AuNP. The regulation of surface plasmon properties of noble metal nanostructure has been a hot topic in the field of nanomaterials preparation and its applications. Surface-enhanced Raman Scattering (SERS), as a sensitive surface-interface trace molecule detection tool, strongly depends on the localized surface plasmonic characteristics. However, how to prepare highly sensitive and reproducible SERS substrates is still under difficult. Herein, Ag/Au hybrid coupled films were attached to the sapphire array by chemical method and interface assembly. Sapphire-based Ag/Au hybrid coupled nanoarrays (SA-Ag/Au HCNAs) with high SERS activity and plasmonic photocatalytic properties were obtained. By monitoring the catalytic reaction of PNTP on the substrate, we found that the prepared SA-Ag/Au HCNAs had significant plasmonic photocatalytic properties. The results show that the synergistic enhancement effect of Ag/Au hybrid coupling is 26.661 times higher than that of pure Au and 9.522 times higher than that of pure Ag. Furthermore, crystal violet (CV), Rhodamine 6G (R6G) and malachite green (MG) were selected as probe molecules, exhibiting good SERS stability and sensitivity of SA-Ag/Au HCNAs substrates. This work provides a simple, low-cost and scalable method for the preparation of hybrid coupled nanoarrays, showing good prospect in photocatalytic dye degradation, environmental monitoring and biomedical analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • SW defect is the most stable defect structure, with the formation energy of 2.067 eV. • The stability of TMN x -Si structures gradually enhances with the increase of N atoms. • CuN 2 -o-Si structure shows the highest quantum capacitance of 145.499 μF/cm2. • Both defects and doping can enhance the quantum capacitance of silicene-based electrode materials. The design of electrode materials with high energy storage properties plays a key role in developing electric double-layer supercapacitor technology. In recent years, silicene has aroused great interest in the field of energy storage. In this paper, the electronic structure and quantum capacitance of single vacancy defects, topological defects and four kinds of double vacancy defects were systematically investigated, based on density functional theory. It is found that silicene with the topological defect is the most stable defect structure, with the formation energy of 2.067 eV. In the systems of Ag, Au, Cu, Ti, Mn and N co-doping on silicene, the structural stability enhances with the increase of N atoms. CuN 2 -o-Si structure shows the highest quantum capacitance of 145.499 μF/cm2, which could be an ideal anode material for supercapacitors. The increased quantum capacitance is due to the introduction of localized states near the Fermi level. Both defects and doping can enhance the quantum capacitance of silicene-based electrode materials, and then improve the total interfacial capacitance. [ABSTRACT FROM AUTHOR]

MOFs-derived metal oxides composites nanofibers composed of MOFs-derived metal oxides nanoparticles and interconnected carbon nanofibers exhibited excellent lithium storage performance. • MOFs-derived metal oxides composites nanofibers with a 3D network were synthesized. • Carbon nanofibers improve the conductivity and structural integrity of based-material. • MOFs-derived composites nanofibers exhibit superior electrochemical performances. The lithium storage performance of metal oxides often suffer rapid capacity fading and poor rate performance due to their huge volume expansion during repeated charge and discharge processes. Herein, a facile strategy was adopted for constructing a three-dimensional (3D) interconnected conductive network. Metal-organic frameworks (MOFs)-derived metal oxides (Fe 2 O 3 , ZnO) were inlayed in carbon nanofibers through electrospinning and subsequent carbonization processes. As lithium-ion storage materials, the MOFs-derived metal oxide composite nanofibers exhibited a high specific capacity and an excellent rate capability due to the unique structural characteristics of high electrical conductivity, additional Li-storage sites, and defined frameworks. The Fe 2 O 3 @polyacrylonitrile (PAN) and ZnO@PAN composite nanofibers deliver high initial specific capacities of 1571.4 and 1053.8 mAh g−1 at 50 mA g−1, respectively. Moreover, Fe 2 O 3 @ PAN and ZnO@PAN composite nanofibers retained reversible specific capacities of 506.6 and 455.4 mAh g−1 at 1000 mA g−1 after 500 cycles, respectively. Additionally, the diffusion kinetics analysis indicated a relatively fast Li-ion diffusivity for the composite nanofibers. [ABSTRACT FROM AUTHOR]

The Co@BN core–shell structure boosts dye-sensitized photocatalysis under shell by confined effect and improvement of the tandem electron transfer. • High EY-sensitized photocatalytic hydrogen evolution activity was achieved. • Enhanced adsorption of EY and Co/BN Schottky junction promotes the electron transfer. • The confined space was a nanoreactor boosting the reduction of H+ to H 2 under shell. • The magnetic recyclability makes Co@BN favorable for its practical application. The Co@BN core–shell nanostructure of Co core and boron nitride (BN) shell was prepared through a facile one-step thermal treatment. The as-prepared Co@BN nanocomposites exhibited excellent dye-sensitized photocatalytic hydrogen evolution activity (13.78 mmol h−1 g−1) with visible light and the apparent quantum yield was 1.15%. The enhanced adsorption of EY on the BN shell and the Co/BN Schottky junction facilitate the tandem transfer of photo-generated carriers to the Co surface. Moreover, the core–shell interface serves as a nanoreactor boosting the reduction of H+ to H 2 on the Co surface. Additionally, the magnetic recyclability makes Co@BN favorable for its practical application. This work extends the application of the "photocatalysis under shell" and has potential in dye-sensitized solar cell. [ABSTRACT FROM AUTHOR]

• Ag quantum dots are assembled on the surface of mesoporous NiMoO 4 microspheres. • Ohmic contact interface boosts the conductivity of the composite material. • Synergistic effects dramatically enhance the specific capacitance of the electrode. • The asymmetric supercapacitor shows high energy density and cycling stability. Nickel molybdate (NiMoO 4) as a ternary metal oxide has great potential as advanced electrode material for energy storage. However, the practical application of NiMoO 4 electrode is hindered by its poor electrical conductivity. In this work, the surface of mesoporous NiMoO 4 microspheres is decorated with silver quantum dots (Ag QDs/NiMoO 4) by means of "dipping and drying". It is interesting to find that an ohmic contact interface (electron anti-barrier layer) generates between the Ag QDs and NiMoO 4 microsphere. Benefitting from the high specific surface area, abundant surface active sites, enhanced interfacial conductivity and porous structure of the Ag QDs/NiMoO 4 microspheres, the composite electrode presents high specific capacitance of 3342.7 F g−1 at 1 mV s−1 and 2074 F g−1 at 1 A g−1 (nearly twice the value of the pristine mesoporous NiMoO 4 microsphere electrode), good rate capability and improved cycling stability. Furthermore, an asymmetric supercapacitor assembled with the Ag QDs/NiMoO 4 microspheres as cathode, spore-derived activated carbon microspheres as anode and 3 M KOH as aqueous electrolyte, reveals a relatively high energy density (48.5 Wh kg−1 at a power density of 212.5 kWh kg−1) and good cycling performance comparing with most of the reported NiMoO 4 -based asymmetric supercapacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • SubPc-3/Ag 3 PO 4 direct S -scheme supramolecular semiconductors were successfully fabricated. • Photocatalytic performance of SubPc-3/Ag 3 PO 4 for organic pollutants improved obviously. • Experimental and theoretical demonstrated the electron transfer mechanism between SubPc-3 and Ag 3 PO 4. • Photodegradation pathways were proposed based on DFT and experimental results. This study demonstrates the successful construction of a hybrid van der Waals heterostructure (vdWH) consisting of 3D supramolecular networks and 2D semiconductor Ag 3 PO 4 , using hydrogen-bonded 3D networks H 12 SubPcB-OPh 2 OH self-assembled onto Ag 3 PO 4. The resulting organic/inorganic vdWH exhibits significantly enhanced photocatalytic degradation efficiency for oxytetracycline (OTC) and tetracycline (TC) under visible light irradiation, with apparent rate constants 1.8 and 1.5 times higher than those of pristine Ag 3 PO 4 , respectively. Moreover, after five photocatalytic cycles, the photocatalytic activity of vdWH was still much higher than that of pristine Ag 3 PO 4. Molecular dynamics simulations indicate that the SubPc-3 supramolecular assembly is more prone to forming a 3D hydrogen bonding network rather than a 1D columnar stacking. In-situ irradiated X-ray photoelectron spectroscopy analyses and theoretical calculations confirm that the charge transfers between H 12 SubPcB-OPh 2 OH and Ag 3 PO 4 are consistent with the S-scheme mechanism. This work provides a promising strategy for designing and fabricating efficient and stable supramolecular self-assembled semiconductor-based photocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Double transition metal atoms on GDY break the scaling relationship. • Machine learning speeds up the screening catalysts and reveals the descriptors. • Relations of intermediate adsorption energies aid catalyst selection in deep CO 2 RR. • GDY-based catalysts with strong CO binding exhibit high selectivity towards CH 4. Electrochemical CO 2 reduction reaction (CO 2 RR) has become a promising application in addressing energy challenges and environmental crises. However, the scaling relationship between the reaction intermediates constrains the successful deep reduction of CO 2. Dual-metal-site catalysts (DMSCs) have emerged as potential electrocatalysts for CO 2 RR by breaking the scaling relationship due to their more adaptable active sites. Herein, this study aims to investigate the correlation between the adsorption energies of essential intermediates in CO 2 RR catalysis with double transition metal atoms anchored on graphdiyne monolayer (TM 1 -TM 2 @GDY) through machine-learning (ML) assisted density functional theory (DFT) calculations. The results reveal the important descriptors of CO 2 RR catalyzed by TM 1 -TM 2 @GDY, and demonstrate that the heteronuclear TM 1 -TM 2 @GDY have great potential for deep CO 2 reduction. Especially, Co-Mo@GDY and Co-W@GDY show low limiting potential (-0.60 V and −0.39 V, respectively) and high selectivity on the reaction from CO 2 to CH 4 based on the free energy diagrams. This study indicates that the two TM atoms on GDY act cooperatively for the catalysis of CO 2 RR. Notably, utilizing ML eliminates the need to calculate all transition metal combinations by DFT, which is a great boost in quickly investigating catalytic performance and high screening for excellent catalysts. [ABSTRACT FROM AUTHOR]

Abstract: We reported a novel method to fabricate hollow silica microspheres using nonionic surfactant nonyl phenol ethoxylated decylether (NP-10) micelles as template, n-octadecane as core and sodium silicate as silica precursor. The core materials were removed by ethanol during the reaction. Hollow structure formed without calcinations or chemical etching. Hierarchical silica hollow microspheres were prepared by changing the concentration of the reactants and reaction time. Size of the core materials was obtained from the temperature-dependent dynamic light scattering (DLS) measurement. Scanning election microscopy (SEM) and transmission electron microscopy (TEM) results revealed that ordered microporous hollow silica microspheres with thickness of shell about 200nm and mean diameter 2.5μm were prepared. Porosity and pore size were analyzed by Brunauer–Emmett–Teller (BET). [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxygen atoms adjacent to Mo in Bi 2 MoO 6 can be removed by UV treatment. • Neutron scattering was used to study the content and structure of defects in Bi 2 MoO 6. • Oxygen vacancies improve the optical properties of Bi 2 MoO 6 /MXene heterojunction. • Oxygen vacancies enhance the reactants adsorption and activation on Bi 2 MoO 6 surface. • Bi 2 MoO 6 /MXene with defects shows high NO removal efficiency under visible light. Defect engineering is an effective approach to improve the gas conversion properties of photocatalysts. However, revealing the defect microstructures and performance enhancing mechanism remain challenges. In this work, the precise content and atomic-level structure of oxygen vacancy in Bi 2 MoO 6 /MXene heterojunction photocatalyst was studied by neutron scattering. Pair distribution function analysis shows that the vacancy percentage of oxygen connected with Mo in Bi 2 MoO 6 is 16.6%, and the metal-O bond length decreases near the vacancy. The performance enhancement mechanism of oxygen vacancy in Bi 2 MoO 6 /MXene towards photocatalytic NO oxidation was investigated through experiments and density functional theory (DFT) calculations. The optical properties of the heterojunction photocatalyst can be significantly improved by the oxygen vacancies. The exposed Mo atoms at the vacancies greatly benefit the adsorption and activation of reactants, and also accelerate the generation of reactive oxygen species. The NO removal efficiency of the oxygen vacancy-containing Bi 2 MoO 6 /MXene heterojunction can reach up to 94.3% under visible light. This work provides a new approach for studying the microstructure and activity enhancement mechanism of oxygen vacancy in photocatalysts. [ABSTRACT FROM AUTHOR]

In the work, visible-light-driven ZnIn 2 S 4 /TiO 2-x nanotube arrays were fabricated by defect-induced bandgap engineering, leading to high visible light responsive, and combining ZnIn 2 S 4 cocatalyst to improve separation of photogenerated carriers, thus enhancing photocatalytic H 2 production. [Display omitted] • A visible-light-driven ZnIn 2 S 4 /TiO 2-x nanotube arrays for fabricating the highly efficient photocatalysts is proposed. • The in-plane oxygen vacancies induce the high visible light responsive of TiO 2-x. • ZnIn 2 S 4 /TiO 2-x nanotube arrays prompt synergistic regulations of both absorption and separation benefits. • ZnIn 2 S 4 /TiO 2-x nanotube arrays exhibit high and stable photocatalytic hydrogen evolution. Photocatalytic H 2 evolution provides an upcoming route for the production of clean fuel via the conversion of solar energy. TiO 2 , as a potential semiconductor material, is restricted by its faint absorption of visible light, thus limiting its application in water splitting. Herein, high visible light responsive ZnIn 2 S 4 /TiO 2-x nanotube arrays for photocatalytic hydrogen evolution were fabricated by two-step reaction. ZnIn 2 S 4 /TiO 2-x nanotube arrays exhibited the photo response from UV to visible-light region due to the introduction of oxygen vacancies and visible-light driven ZnIn 2 S 4. Moreover, the heterojunction improved the separation of photogenerated carriers and boosted the electron transfer from ZnIn 2 S 4 to TiO 2-x , thereby increasing the longevity of active electrons, which enhanced the photocatalytic activity for hydrogen evolution. An outstanding H 2 production rate of 581.1 μmol h−1 g−1 was obtained and an apparent quantum yield (AQY) up to ∼ 1.42% was achieved. This work demonstrates that the defect-induced bandgap engineering of semiconductor photocatalysts is a potential way to extend the optical absorption property of TiO 2 to visible light even or NIR and enhance the photocatalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • 0D/2D CNQDs/BMO-OD was synthesized by NaBH 4 -mediated hydrothermal method. • CNQDs/BMO-OD exhibited superior activity for amines oxidation coupling. • CNQDs/BMO-OD exhibited broad substrates suitability and excellent stability. • Z-scheme and 0D/2D multipoint contact boosted expeditious carriers' separation. • h+ and •O 2 – play a major role in aerobic conditions while only h+ in anerobic. Organic synthesis driven by solar energy is receiving extensive attention due to its inherent merits like higher target product selectivity as well as milder reaction condition. While sluggish photoinduced charge carriers' separation kinetic severely limited its utilization efficiency, leading to inefficient catalytic performance or energy-consuming reaction conditions. Assembling 0D/2D Z-schemed semiconductor nano-heterojunction would be a promising candidate for solving such problem. Herein, 0D/2D carbon nitride quantum dots (CNQDs)/Bi 2 MoO 6-x (BMO-OD) was devised and synthesized by facile NaBH 4 -mediated hydrothermal method. The CNQDs/BMO-OD exhibited superior catalytic activity toward amines oxidation coupling under ambient conditions. Broad substrates suitability as well as excellent photochemical stability implies it would be a robust alternative amines oxidation coupling photocatalyst under mild conditions. The superior photocatalytic performance is attributed to expeditious photoinduced charge carriers' separation and transfer of Z-schemed heterostructures and unique multipoint contact interface of 0D/2D. Scavenger experiments and ESR results demonstrates h+ and •O 2 – radicals play a major role in aerobic conditions while only h+ paly predominant role in anerobic conditions. The design and synthesis of 0D/2D CNQDs/BMO-OD Z-scheme heterostructures would be beneficial for boosting photoinduced carriers' separation kinetic, thus promoting the photocatalytic oxidation coupling of amines under mild conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A uniform appearance is achieved by the introduction of ultrasound. • Ultrasound stimulates the formation of an amorphous Ca, P, Cu and O-rich layer. • Ultrasound is beneficial for corrosion and biological properties of the coating. To achieve a uniform surface layer with enhanced corrosion resistance, antibacterial capability and cytocompatibility on the titanium (Ti)-based orthopaedic implant, ultrasound-auxiliary micro-arc oxidation (UMAO) was carried out on Ti substrate to fabricate a Cu-incorporated TiO 2 coating. Instead of the co-existence of central brown area and peripheral black area in the Cu-incorporated TiO 2 coating fabricated by conventional micro-arc oxidation, a uniform brownish appearance could be achieved after the introduction of ultrasonic vibration (UV). The introduction of UV also significantly modifies the elemental composition, phase component and chemical configuration of the coating, which exhibits a bi-layered structure with the porous TiO 2 as the inner layer and the amorphous Ca, P, O and Cu component as the outer layer. Finally, electrochemical measurement and in vitro biological tests indicate that the introduction of UV is conducive to corrosion resistance, antibacterial capability and cytocompatibility of the Cu-incorporated TiO 2 coating. [ABSTRACT FROM AUTHOR]

Ternary heterojunction CN/TiO 2 -Ti 3 C 2 constructed by CN and partially oxidized Ti 3 C 2 MXene exhibits excellent performance for visible-light photocatalystic NOx removal. [Display omitted] • Ti 3 C 2 MXene can be turned to TiO 2 -Ti 3 C 2 nanosheet by partially oxidation. • Ternary heterojunction catalyst was formed by g-C 3 N 4 and partially oxidized Ti 3 C 2. • NO conversion on the catalyst is inferred to S-scheme heterojunction mechanism. • NO removal efficiency of the photocatalyst reaches up to 66.3% under visible light. Highly efficient composite photocatalysts were prepared through annealing partially oxidized Ti 3 C 2 MXene with melamine under N 2 flow. The two-dimensional Ti 3 C 2 MXene was aforehand partially oxidized to form TiO 2 -Ti 3 C 2 nanosheet by precisely controlling the oxidation conditions. Ternary g-C 3 N 4 /TiO 2 /Ti 3 C 2 MXene photocatalyst was constructed by coating melamine derived g-C 3 N 4 on TiO 2 -Ti 3 C 2 nanosheet. The photogenerated electron-hole separation was significantly enhanced by the S-scheme heterojunction. Ti 3 C 2 tightly bonded with TiO 2 benefits transfer and aggregation of photo-induced holes. The composite material has an interconnected nanosheet structure, which increases the absorption of light and the reaction interface between gaseous reactant and photocatalysts. When evaluated as NOx purification photocatalysts, the fabricated composites get the high NO removal efficiency and low NO 2 generation. Under visible light, NO removal efficiency of the composite photocatalyst can reach up to 66.3%, which is significantly better than the g-C 3 N 4 or TiO 2 -Ti 3 C 2. This work demonstrates that moderately oxidized Ti 3 C 2 MXene is a good candidate for the construction of high-performance air purification photocatalysts. [ABSTRACT FROM AUTHOR]

Abstract: TiO2, which is high in refractive index and dielectric constant, plays an important role in the fields of optics and electronics. In this work, TiO2 films were prepared on glass substrates by the technique of ion beam assisted electron beam evaporation. The films were deposited at 50, 150 and 300°C, respectively. Then the as-deposited TiO2 films were annealed at 450°C for 1h in vacuum atmosphere. Structures and optical properties of TiO2 films were characterized by XRD, SEM, ellipsometry and spectrophotometer. As a result, the structure and the refractive index of films were improved by both the annealing and the increasing of the deposition temperature. The UV–vis transmittance spectra also confirmed that the deposition temperature has a significant effect on the transparency of the thin films. The highest transparency over the visible wavelength region of spectra was obtained at the deposition temperature of 300°C. The allowed direct band gap at the deposition temperature ranging from 50 to 300°C was estimated to be in the range from 3.81 to 3.92eV. [Copyright &y& Elsevier]