In order to optimize the amount of dopant, 3 catalysts with different weight percentages of dopant entered the test medium and it was found that the increase of silver, cerium, nickel. It is one of the factors that accelerates the process of destruction. But this increase works to some extent, and more than this amount will have the opposite effect. In order to optimize the amount of dopant, the oxidative activity of the di benzothiophene compound in a simulated mixture of petroleum derivatives on a set of cerium catalysts as well as nickel deposited on a titanium dioxide substrate was doped with various amounts of Ni dopantin. In general, the oxidant enters the test medium to facilitate degradation. All experiments with the presence of oxidant had a higher efficiency. Therefore, in order to optimize the amount of oxidant, different amounts of them were introduced into the test medium and it was found that increasing the oxidant is one of the factors that accelerates the degradation process, but this increase is somewhat effective and more destructive.