Kockmerritt1295
Facing the demand of cleaning energy, the development of efficient photocatalysts for hydrogen evolution is a promising way to realize solar-to-chemical energy conversion for solving energy crisis. Hence, a novel hierarchical Ti3C2 MXene@TiO2/ZnIn2S4 photocatalyst with rapid charge transfer channels was constructed by two-step hydrothermal for efficient hydrogen production, adopting hydrothermal oxidation to in-situ synthesize Ti3C2 MXene embedded with TiO2 nanosheets (M@TiO2), which was applied to load ZnIn2S4 (ZIS). The hybridized photocatalyst with optimized ZIS amount had a hydrogen generation rate of 1185.8 μmol/g/h, which was higher than that of M@TiO2 and pure ZIS. That was originated from the outstanding light harvesting of ZIS and Ti3C2, sufficient active sites of Ti3C2, intimate interfacial contact, and efficient separation and transfer of photogenerated charges via heterojunction. The favorable and rapid charge transfer routes included type-II heterojunction between ZIS and TiO2 nanosheets, Schottky junction of Ti3C2/semiconductor, and metallic Ti3C2 with high conductivity. This work revealed the Schottky junction forming between ZIS and Ti3C2, and hierarchical M@TiO2 could be served as advantageous platform and efficient cocatalyst to construct MXene-based photocatalyst.Layered double hydroxides (LDH) and their magnetic composites have been intensively investigated as recyclable high-capacity phosphate sorbents but with little attention to their stability as function of pH and phosphate concentration. The stability of a Fe3O4@SiO2-Mg3Fe LDH P sorbent as function of pH (5-11) and orthophosphate (Pi) concentration (1-300 mg P/L) was investigated. The composite has high adsorption capacity (approx. 80 mg P/g) at pH 5 but with fast dissolution of the LDH component resulting in formation of ferrihydrite as evidenced by Mössbauer spectroscopy. At pH 7 more than 60% of the LDH dissolves within 60 min, while at alkaline pH, the LDH is more stable but with less than 40% adsorption capacity as compared to pH 5. The high Pi sorption at acid to neutral pH is attributed to Pi bonding to the residual ferrihydrite. Under alkaline conditions Pi is sorbed to LDH at low Pi concentration while magnesium phosphates form at higher Pi concentration evidenced by solid-state 31P MAS NMR, powder X-ray diffraction and chemical analyses. Sorption as function of pH and Pi concentration has been fitted by a Rational 2D function allowing for estimation of Pi sorption and precipitation. In conclusion, the instability of the LDH component limits its application in wastewater treatment from acid to alkaline pH. Future use of magnetic LDH composites requires substantial stabilisation of the LDH component.
Copolymers are developed to enhance the overall physical and chemical properties of polymers. The surface nature of a copolymer is relevant to creating efficient materials to improve adhesion and biocompatibility. We hypothesize that the improved adhesion, as a surface property, is due to phase separation, surface segregation, and the overall molecular organization of different polymer components at the copolymer surface.
The surface structure of a copolymer composed of 2-hydroxyethyl methacrylate (HEMA) monomer and 2-phenoxyethyl methacrylate (PhEMA) monomer was analyzed in comparison to the polyHEMA and polyPhEMA homopolymers using atomic force microscopy (AFM) and sum frequency generation (SFG) spectroscopy.
The contrast in the phase images was due to the variance in the hydrophobic level provided by the hydroxyl and phenoxy modified monomers in the copolymer. The distribution of the adhesion values, supporting the presence of hydrophobic moieties, across the polymer surface defined the surface segreThe ever-increasing electric vehicles and portable electronics make lithium-ion barreries (LIBs) toward high energy density, resulting in long driving range and standby times. Generally, excellent electrochemical performance can be obtained in thin electrode materials with low mass loadings (10 mg cm-2). In this work, we report a facile method for fabricating nitrogen doped carbon microtubes (N-CMTs) consisted of crumped carbon nanosheets for high-performance LIBs with ultrahigh mass loading, where non-tubular biomass waste (i.e., peanut dregs) is employed as the precursor. Benefiting from the hollow tubular conductive network, high graphitization, and hierarchical structure, the as-synthesized N-CMTs exhibit ultrahigh area capacity of 6.27 mAh cm-2 at a current density of 1.5 mA cm-2 with a high mass loading of 15 mg cm-2 and superior cycling stability for LIBs. Our approach provides an effective strategy for the preparation of nitrogen-doped carbon microtubes to develope high energy LIBs with high mass loading electrodes.
Micron and nano-scale particles are increasingly used to stabilize water-in-oil (W/O) emulsions. L-NMMA Though remarkably stable, the resulting emulsions can be broken by adding low molecular weight surfactants that modify the wettability of the interfacially-adsorbed particles.
W/O emulsions were prepared using lipophilic crystals of the monoglyceride glycerol monostearate (GMS), followed by addition of sorbitan monooleate (SMO) at concentrations below and above its critical micelle concentration (CMC). Systematic measurements of interfacial tension and three-phase contact angles, as well as characterization of emulsion sedimentation and microstructure, were used to assess GMS crystal wettability and emulsion destabilization.
GMS crystals formed shells around the dispersed droplets, resulting in emulsions stable against breakdown under quiescent conditions. With SMO concentrations added below CMC, emulsion stability was not significantly affected. At SMO concentrations above CMC, the integrity of the crystallettability at the oil-water interface was responsible for emulsion breakdown. Findings from this study may provide a pathway for the design of particle-stabilized W/O emulsions with controllable breakdown properties for applications such as tailored release of aqueous bioactive compounds.
The geometric features of charged particles at a fluid-fluid interface substantially affect their interfacial configurations and interparticle interactions (electrostatic and capillary forces). Because lenticular particles exhibit both spherical and nonspherical surface characteristics, an investigation of their interfacial phenomena can provide in-depth understanding of the relationship between the configuration and the interactions of these particles at the interface.
Three types of lenticular particles are prepared using a seeded emulsion polymerization method. Pair interactions at the oil-water interface are directly measured with optical laser tweezers. The numerical calculation of the attachment energy of the particle to the interface is used to predict their configuration behaviors at the interface.
The lenticular particles are found to adopt either an upright or inverted configuration that can be determined stochastically. When the interface contacts the truncated boundary or the biconvex boundary, the local interface deformation-induced capillary attraction likely becomes dominant.
