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Ag@Ga-doped ZnO core-shell nanoparticles show excellent SERS sensitivity, stability and repeatability, which is attributed to its rich surface defects, plasmon- and photo-induced charge-transfer effect by its unique core-shell structure. [Display omitted] • Ag@Ga-doped ZnO core-shell nanoparticles were successfully prepared by simple solvothermal method and defect engineering. • Such SERS substrates exhibits high sensitivity, stability and repeatability. • The detection limit of the substrate for pesticide thiram can reach 10−9 M, which is far lower than the national standard. • The Ag@2.6%Ga-ZnO CSNPs can complete catalytic degradation of organic dye molecule R6G within 40 min. • SERS enhanced mechanism was discussed in detail. There has been increasing interest in evolution of semiconductor-based SERS-active substrates to achieve ultrasensitive detection of trace analyte molecules. This work presents a simple solvothermal method and further defect engineering technology to obtain Ag@Ga-doped ZnO core-shell nanoparticles (Ag@n%Ga-ZnO CSNPs), which have both local electromagnetic enhancement from Ag-core and efficient charge transfer enhancement due to the plasmon and photo-induced electrons and numerous deficiency sites after Ga-doping, for achieving ultrahigh detection sensitivity, stability and repeatability. Specifically, the unique Ag@2.6%Ga-ZnO CSNPs exhibited good linearity in the range from 10−6 to 10−12 M for the typical dye analyte rhodamine 6G (R6G), and the limit of detection could be down to 10−12 M. The Raman signal intensity of the Ga-doped core-shell structure was stable after 60 days of storage at room temperature. Moreover, the as-prepared Ag@2.6%Ga-ZnO CSNPs shows excellent signal repeatability as SERS substrate, and the relative standard deviation (RSD) is calculated to be about 9.71%. To illustrate the usefulness for detection of hazardous substance, we showed that such substrate can detect a pesticide, thiram, at a concentration as low as 10−9 M, which is far lower than the national standard. In addition, due to the construction of the core-shell structure and the introduction of Ga-doping, the photoelectric properties of the material have also been greatly improved. Under the irradiation of xenon lamp, the Ag@2.6%Ga-ZnO CSNPs can complete catalytic degradation of organic dye molecule R6G and pesticide molecule thiram within 40 to 50 min. This study demonstrated that the Ag@Ga-doped ZnO core-shell nanoparticles could serve as an effective and versatile SERS platform for reproducible, fast and in-field detection of organic analytes at trace levels. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new understanding in the active site of CuMnOx catalysts. • CuMnOx catalysts are composed by uniform CuO-Mn 2 O 3 oxide pairs. • Highly isolated CuO nano-particles are essential for CuO-Mn 2 O 3 oxide pairs. • Cu-O-Mn sites are found to be the active sites of CuO-Mn 2 O 3 oxide pairs. The current work provide a new understanding on the active site of CuMnOx catalysts and thus offer a new perspective in the development of highly effective and low cost CuMnOx catalysts for heterogeneous catalytic oxidation reactions. A series of dual-component copper-manganese multi-oxide catalysts (CuMnOx) have been successfully synthesized using a surfactant assisted hydrolysis-hydrothermal method and studied by XRD, N 2 adsorption–desorption test, ICP-AES, SEM, Aberration-corrected HADDF-STEM, HRTEM, FT-IR, Raman, XPS, H 2 -TPR. These CuMnOx catalysts were found to be composed with uniform CuO-Mn 2 O 3 oxide pair structure, in which highly isolated/dispersed CuO species are anchored in the framework of Mn 2 O 3. It was found that the speciation in these CuMnOx catalysts presents a shift from highly isolated or even single Cu2+ oxide species (Cu2+Ox) to CuO nanoclusters and CuO microcrystalline with increasing Cu content. In CO oxidation reaction, which was employed to probe the structure of the CuO-Mn 2 O 3 oxide pairs in these CuMnOx catalysts, the Cu-O-Mn sites in those CuMnOx catalysts with highly isolated or highly dispersed CuO species were found to be highly active. For CuO-Mn 2 O 3 oxide pair catalysts, the highly isolated/dispersed CuO species in Mn 2 O 3 framework is essential to achieve high activity. [ABSTRACT FROM AUTHOR]

Abstract: The hybrid nanoparticles (TiO2-HNPs) with TiO2 nanoparticles as core and with poly(N,N-dimethylaminoethyl methacrylate-co-methyl methacrylate) by using triallylamine as cross-linking agent as shell were firstly prepared via atom transfer radical polymerization (ATRP) in methanol. Then the hybrid nanoparticles with positive charge were produced by the quaternization with methyl iodide as quaternization reagent so as to endow them with greater electrophoretic mobility. The cationic hybrid nanoparticles (TiO2-CHNPs) were studied by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS) measurements. The results indicate that the cationic polymer is successfully grafted on the surface of the TiO2 nanoparticles. The particle size of TiO2-CHNPs is about 150nm and the polydispersity index (PDI) is 0.307. The zeta potential, the contrast ratio of white state to dark state and response time of TiO2-CHNPs are +16.8mV, 30 and 3s, respectively, which show the potential application prospect in the development of electrophoretic ink. [Copyright &y& Elsevier]

Abstract: A novel photocatalyst (Ce, C-codoped titania) was synthesized through a modified sol–gel method under mild condition. The as-prepared sample was investigated by XRD, SEM, DRS and XPS. It was found that the as-prepared photocatalyst was composed of spheroidal particles, which were smaller than undoped ones. The absorbance spectrum of Ce, C-codoped TiO2 exhibited significant red-shift to visible region. It can be ascribed to appearance of a new electronic state in the middle of the TiO2 band-gap. Furthermore, cerium doping could slow the radiative recombination process of photogenerated electrons and holes in TiO2. Accordingly, for degradation of dye Reactive Brillint Red X-3B (C.I. reactive red 2) under visible light, the photocatalytic activity of Ce, C-codoped TiO2 improved much compared to other samples (C-doped TiO2, undoped TiO2 and P25). [Copyright &y& Elsevier]

Electrochemical reduction of carbon dioxide (CO 2 ) to formate is energetically inefficient because high overpotential is required for reduction of CO 2 to formate on most traditional catalysts. In this paper, a novel nano-sized Bi-based electrocatalyst deposited on a Cu foil has been synthesized, which can be used as a cathode for electrochemical reduction of CO 2 to formate with a low overpotential (0.69 V) and a high selectivity (91.3%). The electrocatalyst can show excellent catalytic performance toward reduction of CO 2 which can probably be attributed to the nano-sized structure and the surface oxide layer. The energy efficiency for reduction of CO 2 to formate can reach to 50% when an Ir x Sn y Ru z O 2 /Ti electrode is used as anode, it is one of the highest values found in the literatures and very practicable for sustainable fuel synthesis. [ABSTRACT FROM AUTHOR]

Figures (a) and (b) demonstrate that the Pt NPs were successfully modified on the MCNO-based detector after annealing at 750 °C. The Pt NPs had a diameter of 5–10 nm, which is within the typical size range of quantum dots, thus allowing them to be considered as quantum dots. Pt NPs modification of MCNO film resulted in a remarkable ratio of 73, which is approximately 4.1 times higher than the ratio without Pt NPs modification. This excellent result can be attributed to three factors. Firstly, the barrier created between the NPs and the film reduces the dark current by blocking the transport of carriers. Secondly, the plasma resonance effect of the Pt NPs increases the incident light intensity. Lastly, the extinction of the NPs enhances the absorption of incident light and reduces the surface resistance, leading to a high photocurrent enhancement. These results demonstrate that Pt NPs modification plays a critical role in improving the photoproperties of MCNO-based detectors. [Display omitted] • High quality MCNO films had been deposited on Si substrates by RF magnetron sputtering. • High vacuum in situ annealing plays a critical role in the properties of MCNO-based detectors. • High vacuum in situ 750 °C annealing resulted in a 7.61 on/off ratio for MCNO-based detectors. • Pt nanoparticles modification significantly improved on/off ratio of the device to 38.51. The work developed a series of infrared detectors based on the Mn-Co-Ni-O (MCNO) films, which were grown using a radio frequency (RF) magnetron sputtering technique. It was observed that the characteristics of MCNO films were significantly impacted by the annealing temperature. Elevating the in-situ annealing temperature from 550 to 750 °C improved the performances of MCNO films. Additionally, it was found that in situ annealing was more advantageous than ex-situ annealing of 750 °C for the properties of MCNO films. The response value (light to dark) increased from 2.5 to 17.7 at 15 V bias, representing a 6.08-fold enhancement, and the response time decreased to 11.8 ms from 19.9 ms. Furthermore, sputtering Pt nanoparticles on the surface of the MCNO film further improved the I-V characteristics in the dark, resulting in a high on/off ratio of 38.15, which is five times higher than that without the Pt nanoparticles modification. This impressive improvement in photoproperties can be attributed to the Pt nanoparticles/MCNO film barrier, plasma resonance effect generated by the Pt nanoparticles, the extinction of the Pt nanoparticles, and the reduction of surface resistance caused by the Pt nanoparticles. This highlights the potential of metal nanoparticles in the development of infrared detectors. [ABSTRACT FROM AUTHOR]

• Employing nanosize SiO 2 as precursor for magnesiothermic reduction could effectively alleviate agglomeration in porous Si. • Homogeneous crosslinked porous structure and P doping could improve the electrochemical performance of Si anode. • Phosphoric acid acts as a bifunctional additive to reduce particle size of SiO 2 and achieve P doping of porous Si. The high volume expansion and low electrical conductivity issues severely limit practical application of Si-based materials for Li ion batteries (LIBs). Here we prepare the homogeneous crosslinked phosphorus (P) doped porous Si nanoparticles (P doped pSi) via magnesiothermic reduction of P contained nanosize SiO 2 (P-SiO 2). Phosphoric acid (H 3 PO 4) acts as a bifunctional additive to reduce particle size of SiO 2 and achieve P doping of porous Si. The employment of this modified nanosize SiO 2 as precursor effectively alleviates the agglomeration of Si grains. Besides, the P doping characteristic is quite effective to promote the charge transfer performance of Si anode. Finally, P doped pSi anode displays superior cycle capacity and rate capability in half cells with 1761 mAh g−1 at 0.5 A g−1 after 80 cycles and 700 mAh g−1 at 5 A g−1 even after 400 cycles. Furthermore, the electrochemical performance of P doped pSi//LiFePO 4 full cell is also evaluated. All the results indicate that P doped pSi is an excellent competitor to replace traditional graphite anode for LIBs. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel magnetic Fe 3 O 4 @Tb/AMP ICP core-shell NPs were rationally synthesized. • The ICP NPs showed strong magnetism and selective adsorption ability towards AR/CR. • The adsorbents bear advantage of rapid adsorption rate and high removal capacity. • The adsorbents exhibited stability and high reusability over five cycles. • The adsorbents enabled selective removal of anionic dyes from colored wastewater. Abstract In this study, novel magnetic infinite coordination polymer Fe 3 O 4 @Tb/AMP core-shell nanoparticles were rationally designed and fabricated as recyclable adsorbents for selective removal of anionic dyes from colored wastewater. The core-shell nanoparticles used in this study are composed of two components: the shell is the supramolecular infinite coordination polymers (ICPs) network formed by terbium ions (Tb3+) and adenosine 5 ′ -monophosphate monohydrate (AMP) ligands and the core is the Fe 3 O 4 nanoparticles which are encapsulated into the ICP network by the self-adaptive inclusion process. The prepared core-shell nanoparticles showed superiority in strong magnetism and selective adsorption towards anionic dyes, such as Alizarin Red (AR) and Congo Red (CR). Parameters that influenced the adsorption process, such as solution pH, salt concentration and adsorbent dosage were investigated. Under the optimal conditions, adsorption kinetics, isotherms and thermodynamics were also determined. Notably, this nano-adsorbent exhibited rapid adsorption feature (almost 96% dye removal in 5 min) and the adsorption isotherm data fitted quite well with the Langmuir model with an estimated maximum adsorption capacity of 357.14 mg g−1 for AR and 909.09 mg g−1 for CR at 298 K. This capacity could be further enhanced at the higher temperatures. In addition, the Fe 3 O 4 @Tb/AMP core-shell nanoparticles could be regenerated by a simple salt/ethanol-washing method and used with high recyclability over five cycles. With the magnetically separable Fe 3 O 4 @Tb/AMP core-shell nanoparticles as adsorbents, selective removal of toxic anionic dyes from colored wastewater could be realized directly, which is of great importance for the sustainable development of dye contaminated wastewater treatment technology. [ABSTRACT FROM AUTHOR]

Petal-shaped, folded r-Ni 3 S 2 nanoparticles are prepared with rich sulfur vacancies, which improves the specific capacitance and cycle stability. [Display omitted] • Porous r-Ni 3 S 2 nanoparticles with rich sulfur vacancies are prepared. • More active sites and reduced Gibbs free energy are demonstrated. • Specific capacitance and initial capacitance retention are significantly enhanced. • Theoretical calculation reveals the mechanism of the electrochemical reaction. Metal sulfides derived from metal-organic framework (MOF) have high porosity and easily changed morphology, so they are widely used in supercapacitors. However, they still have a few shortcomings such as poor cycle performance and low specific capacitance. The experiment shows that the generation of sulfur vacancy can optimize its electrochemical performance. Therefore, this work focuses on preparing porous nickel sulfide derived from Ni-based MOF and introducing sulfur vacancies at room temperature. Pleated nanoparticles of r-Ni 3 S 2 that are composed of petal-like flakes were prepared with rich sulfur vacancies. This morphology has a larger specific surface area and sulfur vacancies also exposes more active sites, increases free charge carriers and reduces Gibbs free energy of surface reaction, which will enhance electrochemical performance. It is demonstrated that the specific capacitance increased significantly after the sodium borohydride reduction treatment, and the capacitance retention rate increased by 32 % after 5000 cycles. In addition, the asymmetric supercapacitor of r-Ni 3 S 2 //AC was assembled, which yielded a specific energy density of 33.7 Wh kg−1 at the power density of 1167.8 W kg−1. This research shows great potential in adjusting the crystal structure of compounds to optimize the advanced electrode materials of storage devices. [ABSTRACT FROM AUTHOR]

In this study, magnetic zirconium-iron oxide nanoparticles (MZION) of different Fe/Zr molar ratios were successfully prepared using the co-precipitation method, and their performance for phosphate removal was systematically evaluated. The as-obtained adsorbents were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Zeta potential analyzer, Fourier transform infrared spectroscopy (FT-IR) and Brunauer Emmett Teller (BET) specific surface area analysis. The effects of pH, ionic strength, and co-existing ions (including Cl − , SO 4 2− , NO 3 − and HCO 3 − ) were measured to evaluate the adsorption performance in batch experiments. The results showed that decreasing the Fe/Zr molar ratios increased the specific surface area that was propitious to adsorption process, but the adsorption capacity enhanced with the decrease of Fe/Zr molar ratios. Phosphate adsorption on MZION could be well described by the Freundlich equilibrium model and pseudo-second-order kinetics. The adsorption of phosphate was highly pH dependent and decreased with increasing pH from 1.5 to 10.0. The adsorption was slightly affected by ionic strength. With the exception of HCO 3 − , co-existing anions showed minimum or no effect on their adsorption performance. After adsorption, phosphate on these MZION could be easily desorbed by 0.1 M NaOH solution. The phosphate adsorption mechanism of MZION followed the inner-sphere complexing mechanism, and the surface OH groups played a significant role in the phosphate adsorption. Additionally, the main advantages of MZION consisted in its separation convenience and highly adsorption capacity compared to other adsorbents. [ABSTRACT FROM AUTHOR]

• The Ni1Co3@BC hybrid were prepared with ultrasonic stripping and pyrolysis methods. • The B-doped graphitization structure plays additional active sites for OER activity. • Ni1Co3@BC hybrid exhibits the excellent durability, due to internal active sites were protected coming from the carbon layers. Designing and construction of efficient and robust non-noble-metal electrocatalysts for oxygen evolution reaction (OER) is a pivotal approach in water splitting process. This work developed the dual-metal material system of Ni-Co nanoparticles wrapped in B-doped carbon (Ni1Co3@BC) through simple and economical pyrolysis process for nanosheets NiCo metal-organic framework (Ni1Co3-BDC) precursor. The constitution and structure of characterization were characterized by X-ray diffraction, X-ray photoelectron spectroscopy scanning electron microscope and transmission electron microscope, indicating the homogeneous alloy and less metal boride phase and B doped graphitization structure for Ni1Co3@BC. An optimized Ni1Co3@BC exhibited extraordinary OER performance, providing an overpotential as small as 309 mV at a current density of 10 mA cm−2, a low Tafel slope of 62 mV dec−1 and excellent stability in 1.0 M KOH solution, which attributed to the synergistic effect of inner NiCo alloy, NiCo boride nanoparticles and external B doping carbon structure. The formation of B doped carbon layer not only provides additional active sites but also protects inner metal alloys. This work clearly stated the design and synthesis of desired-morphology features catalysts from controlled MOFs for energy conversation and storage. [ABSTRACT FROM AUTHOR]