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CuO x -decorated TiO 2 (CuO x /TiO 2) nanoparticles have been prepared by the pyrolysis of Cu(II) complex on TiO 2 in an oxygen-limited atmosphere. A solution phase deposition method combined with freeze drying was employed for depositing the 2-methylimidazole-Cu(II) complex onto TiO 2 nanoparticles. The effect of decoration of CuO x on TiO 2 nanoparticles in terms of the crystal phase, morphology, chemical compositions, surface area, surface elemental states, optical absorption and emission properties, was investigated using a series of characterization tools. The oxygen-limited pyrolysis of 2-methylimidazole resulted in the reduction of partial Ti4+ and Cu2+ ions into Ti3+, Cu+ and Cu0 species, respectively. The surface decoration of CuO x was found to improve the separation and migration of photogenerated electron-hole pairs and increase the life time of excitons. Furthermore, the photocatalytic performance of CuO x /TiO 2 nanoparticles was evaluated for hydrogen evolution in aqueous methanol solution under UV–visible light irradiation. The CuO x /TiO 2 photocatalyst with the optimal cocatalyst loading achieved hydrogen evolution rate of 4.34 mmol h−1 g−1, with 71- and 5.5-fold enhancement in activity over neat TiO 2 and CuO x /P25, respectively. It is expected that the combination of deposition and pyrolysis of 2-methylimidazole-Cu(II) complex could be an effective approach for the decoration of Cu and its oxides on other supports. • 2-Methylimidazole was used as a ligand for the decoration of CuO x onto TiO 2. • Multivalent CuO x and Ti3+ species were generated by oxygen-limited pyrolysis. • The decoration of CuO x species improved the photogenerated charge separation of TiO 2. • CuO x /TiO 2 nanoparticles are highly active for photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

This study evaluates the "vector" effects of different microplastics (MPs) on coexisting pollutants. The adsorption of tetracycline was studied on biodegradable plastics poly(butylene adipate- co -terephthalate) (PBAT) and non-biodegradable plastics polystyrene (PS), polypropylene (PP), and polyethylene (PE) after UV aging and chemical aging. The physicochemical properties of PBAT changed more obviously after UV radiation and chemical aging comparing to PS, PP and PE. Pores and cracks appear on the surface of aged PBAT. The crystallinity increased from 29.2% to 52.62%. In adsorption experiments, pristine and aged PBAT had strong vector effects on the adsorption of tetracycline than PS, PP and PE. The adsorption capacity of tetracycline on PBAT was increased from 0.7980 mg g−1 to 1.2669 mg g−1 after chemical aging. The adsorption mechanism indicated that electrostatic interactions and hydrogen bonds contribute to the adsorption process. In addition, for the adsorption of tetracycline on PS, π-π interaction was the main cause, and the adsorption mechanism was not considerably changed by aging. In conclusion, this study demonstrates that biodegradable plastics have substantial vector effect on coexisting pollutants at the end of their life cycle, this contributes to assessment of the risk from microplastic pollution. [Display omitted] • Poly (butylene adipate-co-terephthalate) and polystyrene have higher adsorption rates for tetracycline. • The adsorption capacity of the aged microplastics to tetracycline will be enhanced. • Complex solution environments (pH and salinity) are not conducive to adsorption. • Tetracycline adsorbed by microplastics is more easily released into simulated gastric juice. [ABSTRACT FROM AUTHOR]

ZnS−NiS 2 /g-C 3 N 4 ternary composites were synthesized via a thermal polymerization and post co-deposition−sulfidation method. The decoration of g-C 3 N 4 layers with ZnS−NiS 2 nanoparticles extended visible light absorption and promoted the separation and transfer of photo-generated charge carriers. The photocatalytic performance of the ZnS−NiS 2 /g-C 3 N 4 composites was evaluated by the visible-light-driven hydrogen evolution. Briefly, compared to g-C 3 N 4 , ZnS/g-C 3 N 4 , and NiS 2 /g-C 3 N 4 , the hydrogen evolution rate on ZnS−NiS 2 /CN(0.4) was separately increased by 31, 31, and 1 times, highlighting the synergistic effect of ZnS and NiS 2. The interface between ZnS and g-C 3 N 4 modified the charge separation and transfer process. Meanwhile, NiS 2 with a Pt-like behavior acted as an electron acceptor to facilitate transfer photoelectrons and to provide active sites for proton reduction. This work will offer new insight into improving g-C 3 N 4 -based photocatalysts with mixed metal sulfides for efficient hydrogen evolution. [Display omitted] • ZnS−NiS 2 /g-C 3 N 4 ternary noble-metal-free photocatalyst was synthesized. • ZnS−NiS 2 /g-C 3 N 4 was used for visible light photocatalytic hydrogen production. • NiS 2 could act as an electron acceptor to transfer photoelectron quickly. • The interface formed between ZnS and g-C 3 N 4 facilitated the charge transfer process. [ABSTRACT FROM AUTHOR]

The complex and time-consuming character of the current methods to synthesize cuprous catalysts hampers use of such compounds as replacements for noble metal catalysts for the degradation of organic pollutants. Herein, we report on the development of a simple one-pot method for synthesis of Cu 2 O/Cu nanoparticles. The method was comprised of adding benzyl alcohol during the process of nanoparticle synthesis, where the amount of benzyl alcohol used determined the content of Cu in the obtained nanoparticles. A thorough physicochemical characterization was carried out for the synthesized nanoparticles, where it was found that they could act as catalysts for ultra-fast degradation of phenolics and dyes. Thus, their catalytic activity for the degradation of 4-nitrophenol, methyl orange, and Congo red were evaluated, where pseudo-first-order kinetics were observed. The percentage degradation and rate constant (k app) values were, respectively, 98% (in 60 s) and k app = 61.23 × 10−3 s−1 for 4-nitrophenol, 96% (in 100 s) and k app = 31.5 × 10−3 s−1 for methyl orange, and 97% (in 100 s) and k app = 35.5 × 10−3 s−1 for Congo red. Comparisons with previously reported cuprous catalysts for degradation of these compounds revealed that the Cu 2 O/Cu nanoparticles of the present paper exhibited the fastest degradation rates. [Display omitted] • One-pot method to synthesize Cu 2 O/Cu catalysts by introducing benzyl alcohol. • Cu 2 O/Cu catalysts facilitates the degradation of phenolics and dyes. • Degradation of pollutants within minutes. [ABSTRACT FROM AUTHOR]

A gradient Laponite (Lap)-crosslinked nanocomposite (NC) hydrogel was fabricated by a facile electrophoresis method based on colloidal property of Lap, as well as interaction between Lap and thermo-responsive monomers. TGA, FTIR, SEM and TEM were used to characterize the gradient structure. The gradient NC hydrogel exhibited both gradient distribution of Lap and thermo-responsive polymers under the induction of direct current electric field (DC-EF). The gradient NC hydrogel showed anisotropic mechanical properties and gradient thermo-response along the direction of DC-EF. The mechanical strength of the gradient NC hydrogel increased by 38% compared with isotropic NC hydrogel. An increase in Lap content would improve the mechanical property and extend the strength range in different locations of the gradient hydrogel. Meanwhile, the compressive strength of the gradient NC hydrogels can also be adjusted in the range of 117–1774 kPa by changing the concentration of Lap. The work enabled the gradient NC hydrogels to apply in the field of tissue engineering and provided a new insight into development of novel bionic materials. [ABSTRACT FROM AUTHOR]

Palladium (Pd)-based catalysts supported by silicaluminate materials are potential as the efficient non-mercury catalyst for acetylene hydrochlorination, which is a necessary industrial reaction for producing vinyl chloride monomer. A new strategy was employed to improve Pd/USY zeolite catalysts taking advantage of 4-carboxybutyl triphenylphosphonium bromide ((4-CB)TPPB) for acetylene hydrochlorination. The most active catalyst (Pd@20(4-CB)TPPB/USY) with the 0.5 wt% Pd loadings and the 20 wt% (4-CB)TPPB additives could achieve a stable acetylene conversion of 99.9 % and the vinyl chloride selectivity of 99.7 % during more than 50 h, outperforming the Pd/USY catalyst. The additive of (4-CB)TPPB was preferential to stabilize the catalytic active Pd species, inhibit the Pd (II) reduction and change the surface acidic properties during the preparation process and reaction, hence restraining the carbon deposition. Density functional theory (DFT) calculations further indicate that (4-CB)TPPB additives could effectively enhance the adsorption energy of catalyst for reactants and the desorption energy of vinyl chloride monomer (VCM) products, thus inhibiting the carbon deposition for improving the catalytic performance of Pd/USY catalysts. These findings provide guidance for designing efficient Pd-based catalysts as well as their utilization for acetylene hydrochlorination. [Display omitted] • Pd@(4-CB)TPPB/USY catalysts were prepared and applied for acetylene hydrochlorination. • The catalyst exhibited excellent catalytic performance with 99.9 % C 2 H 2 conversion during 50 h. • The role of (4-CB)TPPB additives were discussed by characterization and DFT calculation. [ABSTRACT FROM AUTHOR]

Supercapacitor, as an energy storage device, the capacitance is highly dependent on the properties of material, including its chemical composition and mesoscopic structure. In this study, we report a promising material, nickel-cobalt layered hydroxide, synthesized by simple hydrothermal co-precipitation. The NiCo hydroxides formed flacks first, and then self-assembled to flower-shape nanostructure. Due to its high surface area and the self-assembled structure, the material allows fast diffusion of ions (Ions have direct access to the material surface in the inner surfaces). Hence, the material was used to construct asymmetrical supercapacitor together with nitrogen-doped graphene aerogel. The energy-density of the supercapacitor reached 32 Wh/kg with the power density of 8027 W/kg. The supercapacitor also overcomes the general problem of short cycle-life with supercapacitor made of NiCo layered hydroxides. [ABSTRACT FROM AUTHOR]

Graphene aerogels have been extensively studied in water treatment and oil remediation. We report a mild and green method to prepare a 3D-columnar graphene aerogel. The aerogel was synthesized by using polyvinyl alcohol (PVA) and stearic acid (SA) as crosslinking agents to construct a framework of reduced graphene oxide (RGO). The interaction between PVA, SA, and stacked RGO sheets created a mechanically very robust aerogel. The aerogel possesses ultra-light performance with the destiny ranging from 4.9 to 10 mg cm −3 . The aerogel also demonstrated ultrafast oil absorption, good fire-resistance, and excellent mechanical properties. The adsorptive capacities are in the range of 105–250 times of its original weight for various organic liquids after the absorption. The aerogel also exhibited a strong durability and reusability, and after ten cycles of absorbing-squeezing, the adsorptive capacity is nearly unchanged, indicating potential application in practical oil remediation. [ABSTRACT FROM AUTHOR]

A new dual nanocomposite hydrogel with excellent mechanical properties have been developed by sol-gel reaction of vinyl triethoxysilane (VTES) and in situ radical polymerization of acrylamide (AM) and VTES in the dispersion of Bentonite (Bent). Unlike conventional cationic surfactant intercalators, VTES was used as both an intercalator and a crosslinker. Good intercalation and exfoliation were confirmed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) results. The covalent interaction between Bent and silica by condensation of VTES was confirmed by Fourier transform infrared spectroscopy (FTIR) and 29 Si solid-state NMR. The compressive stress of the gel reached up to 4.65 MPa with ha huge fracture energy of 6285.59 J m − 2 (water content of 85 wt%). The gel showed a high cross-linking density of 77.17 mol m − 3 by dynamic viscoelastic measurement. The compressive stress increased to above 25 MPa when the water content decreased to 50 wt%. In the tough nanocomposite hydrogel, the nano-scaled SiO 2 was covalently bonded to intercalated or exfoliated Bent and polymer chains, and thus greatly improved the mechanical properties of the gel [ABSTRACT FROM AUTHOR]

Previous studies of Laponite (Lap) in electrolyte solution have revealed a fast aggregation or gelation due to reduced electrostatic repulsion between Lap layers. In this work, the dispersion and stability of Lap in 2-acrylamido-2-methylpropanesulfonic acid (AMPS) solution were explored. Lap in low concentration of AMPS (< 2.0 wt%) were likely to generate aggregation because the formation of electrostatic bonds. In high concentration of AMPS (≥ 2.0 wt%), Lap layers were gradually damaged due to the leaching out of magnesium ions and more likely converted into amorphous silica. So the mutual attraction force between particles was weakened and the phenomenon of aggregation gradually disappeared. However, aging process may convert a well-dispersed fluid into a gel due to electrostatic interaction between sulfonate groups of AMPS absorbed onto Lap and magnesium ions leached out from Lap when the concentration of AMPS range from 2.0 wt% to 5.0 wt%. Besides, rheological tests indicated that Lap/AMPS dispersions changed from pseudoplastic fluids to Newton fluids as the concentration of AMPS increased to 6.0 wt%. The addition of AMPS could also improve the salt tolerance of Lap dispersion. [ABSTRACT FROM AUTHOR]

As the "vector" of heavy metals in the aquatic environment, microplastics (MPs) have a great influence on the migration and transformation of heavy metals. In this study, the adsorption of polypropylene (PP), polyethylene (PE) and polystyrene (PS) on two models of heavy metals after UV aging and environmental variables (ionic coexistence, pH, salinity, and fulvic acid) were comprehensively explored on adsorption. The results show that new oxidation functional groups are formed and their hydrophilicity is enhanced after MPs aging. As a result, the adsorption experiments showed that the adsorption of contaminants by UV aged MPs exceeds that of pristine MPs. The adsorption amounts of Pb(II) and Cu(II) by PP, PE and PS increased by 1.45, 1.46, 1.25 and 1.63, 1.39, 1.22 times, respectively. Adsorption kinetic data were more consistent with the pseudo-second-order kinetic model, proving chemisorption to be the mechanism governing the interaction between metal ions and MPs. The Freundlich model could accurately predict the heavy metal adsorption isotherms on MPs, showing that non-homogeneous multilayer adsorption dominates the process. In Pb(II)–Cu(II) binary composite system, metal ion adsorption capacity on MPs is less than that of the single system adsorption capacity, which proves that there is a specific inhibitory effect between coexisting ions. Additionally, external factors like pH, salinity, and fulvic acid content have a big impact on adsorption behavior. According to mechanism analysis, the adsorption process mainly relies on electrostatic interaction, surface complexation, and van der Waals force. [Display omitted] • The adsorption capacity of heavy metals on microplastics followed the order of PS-UV-11 > PE-UV-11 > PS > PP-UV-11 > PE > PP. • The maximum adsorption amount of metal ions followed the order of Pb(II) > Cu(II). • The adsorption behavior of heavy metals on microplastics was influenced by pH, salinity and fulvic acid. • Adsorption of heavy metals on microplastics is dominated by electrostatic interaction, surface complexation and van der Waals forces. [ABSTRACT FROM AUTHOR]