INTRODUCTION Lead dioxide (PbO2) is widely used for producing ozone 1,2 , for converting organic contaminants electrochemically 3-7 , as electrochemical sensors and as electrosynthesis 8 . The advan- tage of PbO2 is that it is a low-cost material and it has a stabile character physically and chemically as well as a good electro- catalytic activity 9 . Synthesis of PbO2 has been done by the method of electro- deposition in acid electrolytes 1,9-11 . The potential of electro- deposition required is very high i.e., E = 1.7 V 1,12,13 so that a substrate oxide could be formed 14 . In addition, the acid method requires more Pb species reactants, i.e., > 0.1 mol/L 2,6,12,15 . PbO2 electrodeposition can also be performed in alkaline condition at low potential and the amounts of Pb species required are fewer than in acid condition 16,17 . The interesting facts show that acid electrodeposition is more predominant to produce PbO2 with orientation to the β-phase, while base electro- deposition is more to the α-phase 12 . Electrodeposition is a synthesis method of PbO2 which is easily controlled by several optimum parameters 18-20 . Electro- deposition potential and temperature are parameters that can affect the kinetics and diffusion factors 10 . Lowering the potential and the increasing temperatures will increase the crystal size and its crystallographic orientation for both α- phase and β-phase. Electrodeposition of PbO 2 on Ti Substrate in Alkaline Solution: Influence of Fluoride Ions Addition A. MUKIMIN 1,* , K. WIJAYA 2 and A. KUNCAKA 2 1 Center of Industrial Prevention Technology, Semarang, Central Java, Indonesia 2 Department of Chemistry, Gadjah Mada University Jl. Sekip Utara, Post Box: BLS 21, Yogyakarta 55281, Indonesia *Corresponding author: Fax: +62 24 8414811; Tel: +62 24 8316315; E-mail: mukiminaris@yahoo.com Asian Journal of Chemistry; Vol. 25, No. 7 (2013), 3961-3965 (Received: 9 April 2012; Accepted: 18 January 2013) AJC-12732 Titanium-lead dioxide electrode (Ti/PbO2) has been synthesized by the method of anodic electrodeposition from alkaline solutions with a concentration variation of NaF (0.0048-0.0238 M). The results indicated that the presence of F – ions affects the rate of formation of PbO2 which may impact on its properties. SEM analysis showed that the PbO2 film has nanorod-shaped surface morphology with a diameter of 50 nm and a length of 500 nm. X-Ray diffraction study showed that the material was composed of a mixture of α-phase (021; 200; 311) and β-phase (002; 211; 220; 112) whose intensity decreases with an increase on the addition of NaF. Cyclic voltametry results showed a correlation of the electrocatalytic activities with the intensity of phase. The electrocatalytic performance of PbO2 is more likely to be affected by the β-phase (221 and 220) than by the α-phase (021). In other words, the electrocatalytic activity of PbO2 is influenced more by the surface area of the conductivity properties. Key Words: Lead dioxide, Fluoride ions, Electrodeposition, Electrocatalytic, Nanorod. In this paper we studied the effects of adding F – ions on the formation of PbO2 by electrodeposition in alkaline condi- tion and the relationship between the properties of the material synthesized with electrocatalytic activity. The addition of F – ions will serve as a regulator of substance in the electrodepo- sition process based on the fact that the nature of the F – ions is highly electronegative so that it is easy to move to the anode surface without undergoing oxidation reaction because the oxidation potential required is high, which is E = 2.85 V 21 . More interesting facts show that the morphology and compo- sition of α-phase and β-phase of PbO2 can be controlled by the presence of F – ions. EXPERIMENTAL All reagents were analytical grade (Merck) and used as received. The substrate Ti (ASTM B.265 Gr.1) was used to deposit PbO2. Deionized water was used to prepare all solution. Synthesis of Ti/PbO2 electrode: Titanium metal plate (4 cm × 0.5 cm) was smoothened using sandpaper and water solvent followed by silicon paste, soaked in a 30 % solution of NaOH and vibrated for 0.5 h in that solution, then with HCl of 3.75 % for 10 min and finally vibrated (Branson 2510E- MT) in acetone for 0.5 h. The plate was heated at a temperature of 60 ºC for 0.5 h so that the Ti plate becomes dry. Then 7 g http://dx.doi.org/10.14233/ajchem.2013.13858