Surface modification

About: Surface modification is a research topic. Over the lifetime, 35544 publications have been published within this topic receiving 859567 citations.

Nanocomposites of Surface-Modified BaTiO3 Nanoparticles Filled Ferroelectric Polymer with Enhanced Energy Density

Abstract: We report nanocomposites of increased dielectric permittivity, enhanced electric breakdown strength and high-energy density based on surface-modified BaTiO3 (BT) nanoparticles filled poly(vinylidene fluoride) polymer. Polyvinylprrolidone (PVP) is used as the surface modification agent and homogeneous nanocomposite films have been prepared by solution casting processing. The dielectric permittivity of the nanocomposite with treated BT is higher than those with untreated BT and reaches the maximum value of 77 (1 kHz) at BT concentration of 55 vol%. The electric breakdown strength of the nanocomposite is greatly enhanced to 336 MV/m at BT concentration of 10 vol% and the calculated energy density is 6.8 J/cm3. The results indicate that using PVP as surface modification agent can greatly enhance the dielectric permittivity and electric breakdown strength of the ceramic–polymer nanocomposite and achieve high-energy density for energy storage and power capacitor applications.

The smart surface modification of Fe2O3 by WOx for significantly promoting the selective catalytic reduction of NOx with NH3

Abstract: The deposition of WOx species using conventional impregnation method is a very simple and efficient way to adjust the surface acidity and redox ability of hematite Fe2O3 simultaneously, significantly improving its catalytic activity and N2 selectivity for the selective catalytic reduction of NOx with NH3 (NH3-SCR). The deposited WOx species on Fe2O3 surface was in highly unsaturated coordination state acting as an effective surface modifier. Through the electronic inductive effect in W O Fe bonds, the oxidation ability of surface Fe(3+δ)+ species was well increased, yet the over-oxidation of NH3 on bulk Fe2O3 was significantly suppressed, which was quite beneficial to the improvement of NH3-SCR activity and N2 selectivity simultaneously. Besides, the deposited WOx species could also supply abundant surface reactive Lewis and Bronsted acid sites for NH3 adsorption and activation during the SCR reaction. The NH3-SCR process on this WOx/Fe2O3 catalyst mainly followed an Eley-Rideal (E-R) reaction pathway between gaseous NO and active NH3 adsorbed species, which was the main reason for its superior SO2 resistance. This opens a new route for the preparation of highly efficient, selective, cost effective and SO2 resistant NH3-SCR catalysts for the deNOx process on diesel engines.

One-Pot Water-Based Hydrophobic Surface Modification of Cellulose Nanocrystals Using Plant Polyphenols

Abstract: An environmentally friendly procedure for the surface modification of cellulose nanocrystals (CNCs) in water is presented. Tannic acid (TA), a plant polyphenol, acts as the primer when mixed with CNCs in suspension, which are then reacted with decylamine (DA), the hydrophobe. Schiff base formation/Michael-type addition covalently attaches primary amines with long alkyl tails to CNC-TA, increasing the particle hydrophobicity (contact angle shift from 21 to 74°). After modification, the CNC-TA-DA particles in the water phase separate, allowing for easy collection of modified material. The dried product is readily redispersible in toluene and other organic solvents, as demonstrated by turbidity measurements, dynamic light scattering, optical microscopy, and liquid crystal self-assembly behavior. Electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, solid-state 13C NMR, and X-ray diffraction support the successful surface modification and indicate that CNC particle mo...