W.H. Leng

Photoelectrocatalytic degradation of aniline over rutile TiO2/Ti electrode thermally formed at 600 °C

Abstract The photoelectrochemical oxidation of aniline on rutile form TiO 2 film electrodes prepared by direct thermally oxidation of titanium sheet was studied both in single and double compartment photoreactor. The results showed that the rutile form of TiO 2 /Ti electrode had excellent photoactivity by applying anodic bias potential and irradiation simultaneously. Oxygen and its reduction products could accelerate the oxidation rate of aniline though its supply was not necessary in this system. The oxidation rate of aniline performed in single compartment cell was larger than that in double compartment cell under the conditions of either by nitrogen or air purging. The oxidation rate could be evaluated by the photocurrent, but it was dependent on the presence of oxygen. The photocurrent efficiency for aniline degradation was related to potential, pH, and single/double compartment cell. Total mineralization of aniline requires a much longer illumination time than its disappearance.

Study on the behavior of Zn–Fe alloy electroplating

The electroplating behavior of Zn, Fe and Zn-Fe alloy onto copper from light acid chloride solutions (LACS, pH 3.07 containing H3BO3, Na2C6H5O7. 2H(2)O and different amounts of Zn2+ and Fe2+) was investigated by means of cyclic voltammetry and the steady-state polarization technique. It was found that, in the experimental conditions, during the Zn-Fe alloy formation no underpotential deposition (upd) was observed, and the deposition of Zn-Fe followed the mechanism of three-dimensional (3-D) nucleation and subsequent grain growth. The Zn2+ ions in the electrolyte inhibit the deposition of Fe, while Fe2+ ions promote the deposition of Zn. It was also found experimentally that the co-deposition of Zn and Fe behaved anomalously, and the result was interpreted theoretically in the light of quantum chemistry

Cooperation behavior of iron and phosphorus in electrodeposition of zinc-iron-phosphorus coating

The co-operation behavior of iron and phosphorus in clectrodeposition of Zn-Fe-P alloy onto copper from light acid chloride solutions (LACS) was investigated by means of cyclic voltammetry and steady-state polarization techniques. It was found that, under the experimental conditions, the phosphorous and the iron promote the reduction of each other and their contents in Zn-Fe-P coating change synchronously, which has been interpreted theoretically in the view of quantum chemistry. The theoretical results showed that, because the orbital radius of 4S of iron atom is shorter than that of zinc atom, the overlapping integral of iron and phosphorus (SFe-P) is smaller than that of zinc and phosphorus (SZn-P) which resulted in the synchronous variation of the contents of the phosphorus and the iron in the electrodeposits, and which also showed that there exist the cooperative effect of phosphorus with iron series metal among their co-depositing coatings

DECREASING PITTING SUSCEPTIBILITY OF PASSIVE FILMS ON X70 PIPELINE STEEL IN NaCl SOLUTIONS BY ILLUMINATION

The influence of UV illumination on passivity and pitting susceptibility on ×70 pipeline steel in a borate buffer (pH = 8.4) solution containing NaCl is described. It is observed that illumination of the sample leads to a decrease in its pitting susceptibility as indicated by pitting potential and incubation time measurements in chloride containing electrolytes. This effect is strongly dependent on the applied potential during passivation. The electronic properties of the passive films on ×70 steel were studied by Mott-Schottky analysis and photocurrent transient measurements. The results indicated that illumination during passivation led to modifications in the electronic properties of the passive films, mainly to a decrease of the bulk doping and an increase in the surface state density. The cause for the decrease in the pitting susceptibility is preliminary explained in terms of such modifications of the passive film.

Investigation of the Secondary Current Distribution in a Hull Cell

A new equation of secondary current distribution of the Hull cell is derived which can explain the influence of some electrochemical kinetics and mass transport on the quality of electrodeposit, and can give some instructions for the electroplating using indirect current and for the study of secondary current distribution in a modified Hull cell. The results from the theoretical equation and experimental measurement are compared with that of other experimental formula. It is shown that the result from the theoretical equation is more suitable to the actual conditions than that from the empirical formula