In 1904, he returned to St. Petersburg University to work under Alexey Favorsky (Stalin Prize, 1941, for contributions to the manufacture of synthetic rubber).

[2] After 1914, he studied polymerisation of ethylene monomers, leading to modern industrial methods for manufacturing of butyl synthetic rubber and poly-isobutylene.

In 1928, he developed an industrial method for producing synthetic rubber based on polymerisation of butadiene using metallic sodium as a catalyst.

During World War II, Lebedev's process of obtaining butadiene from ethyl alcohol was also used by the German rubber industry.

[4] Another important contribution of Lebedev's was the study of the kinetics of hydrogenation of ethylene hydrocarbons and the development of a number of synthetic motor oils for aircraft engines.