Abstract: An apparatus for friction reduction and biofouling prevention is invented, which consists of an anodic electro-catalytic layer and a cathodic electro-catalytic layer installed on the submerged surface of a carrier. There is an insulating filling between the anodic layer and the cathodic layer. The layered coatings are applied with the use of electric arc spraying technique. A first DC power supply unit is connected to the anodic layer and the cathodic layer. The anodic layer, the cathodic layer, the DC power supply unit, and water together form the conducting path for water electro-catalysis. Hydrogen and oxygen gases are produced to form a thin gas film on the submerged surface to reduce friction and prevent biofouling on the carrier. Alternatively, the apparatus produces hydroxyl radicals to kill marine microorganisms and reduce the risk of biofouling and biocorrosion.