Alexander Naumovich Frumkin (Алекса́ндр Нау́мович Фру́мкин) (October 24, 1895 – May 27, 1976) was a Russian/Soviet electrochemist, member of the Russian Academy of Sciences since 1932, founder of the Russian Journal of Electrochemistry Elektrokhimiya and receiver of the Hero of Socialist Labor award. The Russian Academy of Sciences' A.N. Frumkin Institute of Physical Chemistry and Electrochemistry is named after him.
Frumkin was born in Kishinev, in the Bessarabia Governorate of the Russian Empire (present-day Moldova) to a Jewish family; his father was an insurance salesman. His family moved to Odessa, where he received his primary schooling; he continued his education in Strasbourg, and then at the University of Bern. Frumkin's first published articles appeared in 1914, when he was only 19; in 1915, he received his first degree, back in Odessa. Two years later, the seminal article "Electrocapillary Phenomena and Electrode Potentials" was published.
Frumkin moved to Moscow in 1922 to work at the Karpov Institute, under A.N. Bakh. In 1930 Frumkin joined the faculty of Moscow University, where in 1933 he founded—and would head until his death—the department of electrochemistry.
During the Second World War, Frumkin led a large team of scientists and engineers involved in defense issues. This contribution did not save him from being dismissed in 1949 as the director of the Institute of Physical Chemistry, when he was accused of "cosmopolitanism".
Frumkin's most fundamental achievement was the fundamental theory of electrode reactions, which describes the influence of the structure of the interface between electrode and solution on the rate of electron transfer, especially emphasizing the involvement of the solvated electron and its free energy of solvation. This theory has been confirmed and extended within the framework of contemporary physical electron transfer models. Frumkin introduced the concept of the zero charge potential, the most important characteristic of a metal surface.
Alessandro Volta's question—a topic of discussion for over 120 years—about the nature of the EMF of electrochemical circuits was resolved using Frumkin's approach. Frumkin has developed the Frumkin isotherm, an extension of the Langmuir isotherm in describing certain adsorption phenomena. Frumkin's students developed novel experimental methods that would, in time, become standard. Several applied electrochemical processes, including ones related to chemical sources of electrical power, industrial electrolysis, and anti-corrosion protection, were successfully developed under Frumkin's supervision.
Frumkin was married three times, including a brief first marriage to Vera Inber.
Frumkin was nominated for Nobel Prize in Chemistry in 1946, 1962, 1963, 1964, 1965 and 1966, but he did not receive the Prize.