Electrodeposition of Sb(Ⅲ) in alkaline solutions containing xylitol
(1. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China;
2. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
2. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China)
Abstract: The electrodeposition of antimony in alkaline solutions containing xylitol was investigated using cyclic voltammetry, linear sweep voltammetry and chronoamperometry. The antimony electrodeposition and the chemical stability of xylitol in alkaline solutions were studied by cyclic voltammetric technique. Apparent activation energy, apparent transfer coefficient and exchange current density were obtained by linear sweep voltammetric technique. Initial stages of antimony electrocrystallization were determined by chronoamperometry. Xylitol in alkaline solutions exhibits high chemical stability and there is no redox in solutions when the potential ranges from −1.20 V to +0.60 V (vs Hg/HgO). There is no other redox reaction but hydrolysis occurring on stainless steel in the potential range of −1.75 V to 1.25 V (vs Hg/HgO) while the xylitol decomposition maybe take place on antimony electrode when potential is more negative than −1.70 V (vs Hg/HgO). Cyclic voltammograms with different scan rates indicate that the antimony electrodeposition process is an electrocrystallization which is a completely irreversible electrode process. The apparent activation energy, apparent transfer coefficient and exchange current density were calculated to be 46.33 kJ/mol, 0.64 and 4.40×10−6 A/m2, respectively. The analyses of the chronoamperometric responses support the view of a three-dimensional growth under progressive nucleation. The average diffusion coefficient of antimony was calculated to be 1.53×10−6 cm2/s.
Key words: antimony electrodeposition; xylitol; electrocrystallization; cyclic voltammetry; chronoamperometry