From integration surface area of figure 4 found that the active area of Pt electrodeposited is 0.0251 cm2. When there is compare with geometric surface area, it is 0.0709 cm2. The value of experiment had been more than theory value approximately 12.14 folds of geometric surface. The cause lead to the surface area active is vary because the solution form with electrodeposited, are not react with some surface area. So, it affects to attract hydrogen in solution. Moreover, many factors that there are lead to attract hydrogen atoms, such as, the concentration of electrolyte, scan rate, voltage, current, or variable of another molecule.