Disclosed is a method for providing photochemical activity by coating a nano-layer of metallic oxide with nano-sized micropores on the particles or film of titanium dioxide (TiO2). The method for coating the nano-layer of porous oxides with hyperfine nano-sized pores on titanium dioxide (TiO2), comprising producing the solution containing metallic salts, providing the solution of metallic salts with TiO2 powder, hydrating the metallic salts and coating the hydrates on the TiO2 powder surface, and forming oxides from the hydrates coated on the TiO2 powder surface. The formed porous oxide coating layer increases the absorption capacity of water or dye molecules by increasing the specific surface area of titanium dioxide (TiO2) particles, thereby improving a photocatalyst characteristic or dye-sensitized fuel cell characteristic of TiO2.