Acid or Alkaline solutions are used to split water. An alkaline electrolyte is ideal prevention of corrosion which occur when using acids. Highly concentrated potassium hydroxide (KOH 25-30%) is often used. A large contact surface area among electrodes with electrolytes is needed for the correct process. The final product is then separated from the electrodes. Low-carbon steel, sometimes covered with a thin layer of nickel, is used for cathodes. Anodes are made of nickel-plated low-carbon steel or nickel steel. Platinum is seldom used as a catalyst. A diaphragm separates electrodes to avoid a reaction between produced hydrogen and oxygen. Earlier, the diaphragm was made of asbestos, but due to the risks it imposes on our health, it was banned, and new materials were tested.