Chemical conversion coating as an effective corrosion inhibition has wide range of applications in industries and is of great expectation to be environmentally friendly and costeffective. Zirconium-based (Zr-based) conversion coating using hexafluorozirconic acid with copper (Cu) additive on low carbon steel which improves anticorrosion and adhesion properties was studied using synchrotron X-ray and electron-based techniques. To understand the elemental evolution during coating formation process, in situ synchrotron X-ray fluorescence (XRF) microscopy has been applied to observe Zr, Cu, iron (Fe), and zinc (Zn) concentration evolution. By quantifying the density, average size, and size distribution of the cluster as a function of time and temperature, the growth mechanism of the coating can be concluded as a reaction-controlled mechanism. X-ray absorption near edge structure and X-ray photoelectron spectroscopy (XPS) were used to characterize the composition of the Cu-rich clusters embedded in the coating which was determined to be mainly Cu 2 O, Cu, and CuF 2 ; the cluster composition varies from the surface to the internal region as determined by the depth-profiling of XPS. Our study shed light on the chemical and morphological evolution in environmentally friendly surface conversation coating and demonstrated new methodology in studying the coating formation via in situ synchrotron XRF.
This paper reported for the first time a comparative study of the photocatalytic activity of the Keggin-type Mn(II)-substituted heteropolyanion PW 11 O 39 Mn II (H 2 O) 5− (PW 11 Mn) and its heterogeneous system PW 11 Mn/D301R through the degradation of rhodamine B (RhB) under visible light irradiation. A novel photocatalytic mechanism was suggested, and an interaction between PW 11 Mn and RhB was scrutinized by using visible absorption spectrum and fluorescence emission spectrum. Influences of some factors such as the RhB initial concentration, the PW 11 Mn concentration, the PW 11 Mn/D301R dosage, the solution pH, and different anions existing in solution on the photocatalytic degradation rate of RhB were also examined. The stability of PW 11 Mn/D301R was evaluated by the cycle photodegradation of RhB in the end. The experimental results showed that 100% of RhB degradation was reached at 100 min for the PW 11 Mn system and 40 min for the PW 11 Mn/ D301R system when the solution containing 10 μmol•L −1 RhB was exposed to visible light. The hydroxyl radicals were responsible for the destruction of dye. The photocatalysis mechanism was different from that of both semiconductor and Keggin parent catalysts. An electrostatic interaction and a coordination interaction between PW 11 Mn and RhB occurred simultaneously in an acidic aqueous solution. The coordination interaction slowed significantly the RhB degradation, but became weak obviously after PW 11 Mn was adsorbed onto the D301R resin. The influence of anions existing in solution on the RhB degradation followed the sequence of PO 4 3− > SO 4 2− > Cl − > NO 3
−. No matter if in neutral or in acidic aqueous solution, the photocatalyst PW 11 Mn/D301R was stable.
One-dimensional (1D) titanium trisulfide (TiS 3 ) nanobelt bundles up to 4 cm in length have been successfully synthesized through an easy and common chemical vapor transition (CVT) process. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), polarized light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). All microscopic observations indicated a belt-like morphology. Powder XRD patterns showed that TiS 3 crystallized in the monoclinic system with a = 4.958(1) Å, b = 3.393(1) Å, c = 8.793(3) Å and β = 97.27(5)°. TEM images revealed a nanostructure with an interplanar spacing of 0.87 nm. The ED pattern and HRTEM images con-
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