One-step synthesis of monodisperse polydopamine-coated silver core–shell nanostructures for enhanced photocatalysis

Abstract

Nanosized silver (Ag) and polydopamine (PDA) composite was prepared via one-step polymerization of dopamine, using Ag + ion as an oxidant. The oxidization of dopamine and the reduction of Ag + ion occurred simultaneously in one-step, which resulted in a well-defined core-shell structure of PDA coating around the Ag nanoparticles (AgNPs). Its morphology, structure, and composition were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray power diffraction (XRD), UV-vis, Fourier transform infrared (FT-IR) spectroscopy, cyclic voltammograms (CVs) and electrochemical impedance spectroscopy (EIS), respectively. The composite showed good performance toward the photo-catalytic degradation of neutral red under UV irradiation. The possible mechanism regarding the plasmon-induced photocatalysis was discussed in some detail, where the main active species of O 2 À on the surface of the AgNPs were involved in this photoreaction system. The PDA shells greatly improve the photocatalysis due to the existence of the p-p* electron transition under UV light.

Charge-Switchable Integrated Nanocatalysts for Substrate-Selective Degradation in Advanced Oxidation Processes

“…13,14 The PDA coated functional materials have also exhibited many advantageous features such as enhanced conductivity, biocompatibility, high stability, antioxidation, and strong light absorption; their applications have included catalyst modification, water purification membranes, enzyme immobilization, lithium ion batteries, biosensors, and biomedical application, etc. [15][16][17][18][19][20][21] Although the structure of PDA is still not elucidated unambiguously at present, it has been generally accepted that this macromolecule is an ampholyte polymer owning a great deal of amino groups and phenolic hydroxyl groups. 22 Consequently, PDA exhibits zwitterionicity: it has a net negative charge at high pH that excludes anions but passes cations, whereas it becomes positively charged at low pH that attracts anions instead of cations.…”

Natural melanin pigments and their interfaces with metal ions and oxides: emerging concepts and technologies

“…[103,116] Polydopamine/TiO 2 nanocomposites and plasmonic structures fabricated exploiting the reducing properties of polydopamine have been used for photocatalytic applications. [117][118][119] The biocompatibility and optical properties featured by TiO 2 have been used for self-cleaning, self-sterilization, and photolithography purposes [120,121] and also in fields such as cosmetics, where TiO 2 has been used as filler and UV-filter. [122] To ensure transparency to cosmetic formulations, the average dimension of TiO 2 particles has been typically of the order of 10-20 nm.…”

Liquid–liquid interfacial behavior of dopamine modified poly(γ-glutamic acid) polymer

“…Previous research work had coatings for diverse uses due to the excellent surface adhesion property [4][5][6][7][8][9][10].…”