Novel hollow Pt-ZnO nanocomposite microspheres with hierarchical structure and enhanced photocatalytic activity and stability

Abstract

Noble metal/semiconductor nanocomposites play an important role in high efficient photocatalysis. Herein, we demonstrate a facile strategy for fabrication of hollow Pt-ZnO nanocomposite microspheres with hierarchical structure under mild solvothermal conditions using Zn (CH(3)COO)(2)·2H(2)O and HPtCl(4) as the precursors, and polyethylene glycol-6000 (PEG-6000) and ethylene glycol as the reducing agent and solvent, respectively. The as-synthesized ZnO and Pt-ZnO composite nanocrystals were well characterized by powder X-ray diffraction (XRD), nitrogen-physical adsorption, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy. It was found that Pt content greatly influences the morphology of Pt-ZnO composite nanocrystals. Suitable concentration of HPtCl(4) in the reaction solution system can produce well hierarchically hollow Pt-ZnO nanocomposite microspheres, which are composed of an assembly of fine Pt-ZnO nanocrystals. Photocatalytic tests of the Pt-ZnO microspheres for the degradation of the dye acid orange II revealed extremely high photocatalytic activity and stability compared with those of pure ZnO and corresponding Pt deposited ZnO. The remarkable photocatalytic performance of hollow Pt-ZnO microspheres mainly originated from their unique nanostructures and the low recombination rate of the e(-)/h(+) pairs by the platinum nanoparticles embedded in ZnO nanocrystals.

Selective isolation of the electron or hole in photocatalysis: ZnO–TiO2 and TiO2–ZnO core–shell structured heterojunction nanofibers via electrospinning and atomic layer deposition

“…[1][2][3][4][5][6][7][8][9][10][11] Understanding the catalysis mechanism is vital for the design of new functional materials to be a part of an environmentally friendly technology. The catalytic process on the surface of a semiconductor has been proposed by Izumi et al 12 and Matthews.…”

Transformation of polymer-ZnO core–shell nanofibers into ZnO hollow nanofibers: Intrinsic defect reorganization in ZnO and its influence on the photocatalysis

“…It is known that delaying the recombination of photogenerated electron-hole pair increases the efficiency of the catalysts [10,12,[15][16][17][18][19][20][21][22][23]. On the other hand, the efficiency of the catalyst is dependent on the crystal-phase [1,3].…”

“…This not only minimizes the usage of catalyst but also enhances the active sites on the surface [10][11][12][13]18]. One should note that other significant attempts of enhancing the photocatalytic activity (PCA) or delaying the recombination are lattice defects [12,16,[18][19][20][21][22][23], heterojunctions [4,10,[14][15][16][17][24][25][26] etc. It is also notable that PCA is a very complex process and it is an integral effect of surface sites, bulk of the lattice etc.…”

One Pot Synthesis of Pt/Graphene Composite Using Polyamidoamine/Chitosan as a Template and Its Electrocatalysis for Methanol Oxidation

“…Boppella et al [1] reported the formation of oriented ZnO structures with tunable percentage of exposed polar facets via a simple hydrothermal route in aqueous base environment. Yu et al [2] demonstrated unique hollow Pt-ZnO nanocomposite microspheres with hierarchical structure under mild solvothermal conditions. Especially, this method has an advantage for the synthesis of graphene-based nanomaterials due to the possible synchronous reduction of graphene oxide and the corresponding metal precursors [3,4].…”