In 2011, he graduated from the Master's program at the People's Friendship University of Russia (RUDN), where he subsequently enrolled in postgraduate studies. In 2013, he defended his PhD dissertation on the topic "Geology, Mineralogy and Conditions of Formation of the Tikhmenevskoye Bentonite Deposit (Sakhalin Island)". Since 2011, he has been working at IGEM RAS as a Junior Researcher.

Petr is a member of the State Examination Commission at the People's Friendship University of Russia (RUDN), an expert of the Russian Science Foundation (RSF), Secretary of the Russian Clay and Clay Minerals Group, a member of the Russian Mineralogical Society, and a reviewer for MDPI Publishing. He is a performer of state assignment projects at IGEM RAS, RFBR projects, and international projects. He is also a principal investigator and performer of RSF projects.

P.E. Belousov is a specialist in the study of geology, mineralogy, formation conditions, and applications of non-metallic minerals: bentonite clays, kaolinite, glauconite, zeolites, carbonate rocks, diatomite, tripoli, opoka, and others. He studies terrigenous-diagenetic and hydrothermal mineral-forming systems. He conducts research on the mineral resource base and properties of natural sorbents, as well as their sorption properties with respect to radionuclides. He is engaged in refining the formation conditions and mineral composition of weakly gold-bearing argillisites of the Far East. He has participated in fieldwork at various deposits in Russia, neighboring countries, and abroad. He has over 50 publications (including 8 publications in the WoS list).