A photo catalyst of cuprous oxide anchored MXene nanosheet for dramatic enhancement of synergistic antibacterial ability

Ti3C2Tx (MXene) as a two-dimensional material has attracted numerous attentions in photocatalysis and antibacterial, and the effectiveness of MXene for photocatalysis triggered antibacterial is in urgent need of development. Herein, we synthesized a novel cuprous oxide (Cu2O) anchored MXene nanosheet. Cu2O nanospheres can be uniformly anchored on the surface of MXene firmly due to the electrostatic effect between single-layer MXene and Cu2O nanospheres. In comparison with MXene, Cu2O and mixture (MXene and Cu2O), Cu2O/MXene nanosheet exhibits an excellent antibacterial activity against S. aureus and P. aeruginosa, whose bacteriostasis efficiencies sharply increased to 97.04% and 95.59%, respectively. Photoluminescence spectroscopy reveals that the incorporation of MXene and Cu2O can effectively prevent the recombination of electron-hole pairs of Cu2O and present a high photocatalytic disinfection. Single-layer MXene with large surface area accepts electrons from Cu2O, leading to abundant electrons on the surface of MXene, which provide better charge transfer between bacteria and Cu2O/MXene nanosheets. In addition, density functional theory calculations were used to investigate an optimized band structure of Cu2O-MXene as well as its strong electronic interactions, which are essential for photocatalysis and ROS generation. Finite element method further revealed that MXene promoted an enhancement of surface plasmon resonance to generate ROS on the surface of Cu2O/MXene. Furthermore, Cu2O/MXene shows a synergistic antibacterial effect of MXene accelerating photoelectron transportation, Cu2O antimicrobial and photocatalysis, elevated ROS production ability, and surface plasmon resonance action on the surface of Cu2O/MXene

Monodisperse Fluorescent Organic/Inorganic Composite Nanoparticles: Tuning Full Color Spectrum

Monodisperse fluorescent organic/inorganic composite nanoparticles are synthesized through the spontaneous self-assembly of block copolymer polystyrene-<i>block</i>-poly­(vinylpyridine) and rare-earth ions (europium, terbium, thulium, etc.). Depending on the rare-earth ions selected, tunable light-emission colors, including the primary red, green, and blue, are accomplished. Further, by stoichiometric mixing of the nanoparticles that emit different colors, the full color spectrum can be accessed. Both electron microscopy and spectroscopic characterizations confirm specific interactions of rare-earth and block copolymers. The resulting nanoparticles are monodisperse as characterized by dynamic light scattering. They are very stable and can be dispersed in common solvents, and together with homopolymers, they form ordered arrays and thin films (both supported and free-standing) upon solvent evaporation. The resulting nanoparticle thin films exhibit mechanical flexibility for ease of processing or device integration

Interfacial Self-Assembly Driven Formation of Hierarchically Structured Nanocrystals with Photocatalytic Activity

We report the synthesis of hierarchical structured nanocrystals through an interfacial self-assembly driven microemulsion (μ-emulsion) process. An optically active macrocyclic building block Sn (IV) <i>meso</i>-tetraphenylporphine dichloride (tin porphyrin) is used to initiate noncovalent self-assembly confined within μ-emulsion droplets. <i>In-situ</i> studies of dynamic light scattering, UV–vis spectroscopy, and electron microscopy, as well as optical imaging of reaction processes suggest an evaporation-induced nucleation and growth self-assembly mechanism. The resulted nanocrystals exhibit uniform shapes and sizes from ten to a hundred nanometers. Because of the spatial ordering of tin porphyrin, the hierarchical nanocrystals exhibit collective optical properties resulting from the coupling of molecular tin porphyrin and photocatalytic activities in the reduction of platinum nanoparticles and networks and in photodegradation of methyl orange (MO) pollutants

Porous One-Dimensional Nanostructures through Confined Cooperative Self-Assembly

We report a simple confined self-assembly process to synthesize nanoporous one-dimensional photoactive nanostructures. Through surfactant-assisted cooperative interactions (e.g., π–π stacking, ligand coordination, and so forth) of the macrocyclic building block, zinc meso-tetra (4-pyridyl) porphyrin (ZnTPyP), self-assembled ZnTPyP nanowires and nanorods with controlled diameters and aspect ratios are prepared. Electron microscopy characterization in combination with X-ray diffraction and gas sorption experiments indicate that these materials exhibit stable single-crystalline and high surface area nanoporous frameworks with well-defined external morphology. Optical characterizations using UV–vis spectroscopy and fluorescence imaging and spectroscopy show enhanced collective optical properties over the individual chromophores (ZnTPyP), favorable for exciton formation and transport

Morphology-Controlled Self-Assembly and Synthesis of Photocatalytic Nanocrystals

Abilities to control the size and shape of nanocrystals in order to tune functional properties are an important grand challenge. Here we report a surfactant self-assembly induced micelle encapsulation method to fabricate porphyrin nanocrystals using the optically active precursor zinc porphyrin (ZnTPP). Through confined noncovalent interactions of ZnTPP within surfactant micelles, nanocrystals with a series of morphologies including nanodisk, tetragonal rod, and hexagonal rod, as well as amorphous spherical particle are synthesized with controlled size and dimension. A phase diagram that describes morphology control is achieved via kinetically controlled nucleation and growth. Because of the spatial ordering of ZnTPP, the hierarchical nanocrystals exhibit both collective optical properties resulted from coupling of molecular ZnTPP and shape dependent photocatalytic activities in photo degradation of methyl orange pollutants. This simple ability to exert rational control over dimension and morphology provides new opportunities for practical applications in photocatalysis, sensing, and nanoelectronics