The book opens with a study wherein it is proposed that, according to the electrolyte composition and the parameters of an applied electric signal, it is possible to obtain either barrier or porous oxide films with precisely controlled dimensions. The authors examine how exhaust gases purification and diesel oxidation catalysts are of paramount importance, since the requirements for the automobile emission control become more and more strict each year. Aluminum oxide has historically been used as a component of such purification systems. The subsequent study suggests that it is possible to affect the concentration of Lewis and BrÃ,nsted acids, the desired specific surface area, and the degree of crystallinity in catalytic processes.