It was in Munich (1928–1938) that Schwab started systematic work on heterogeneous catalysis which marked the rest of his career. Among the catalysis-related topics he studied in Munich were the kinetics of heterogeneously catalysed reactions, the nature of the heat of adsorption, the poisoning of catalysts and the spatial distribution of active catalytic sites. He also collaborated with his future wife Elly on her research about the influence of free radicals on parahydrogen, a work which they completed in Greece.
In the Kanellopoulos Institute (1939–1950), with the academic freedom he was given Schwab produced research on various occasional topics such as inorganic chromatography (which he is credited with inventing), turn-over transitions, carbon adsorption and properties of parahydrogen. He also built on his previous work with a series of kinetic studies, which eventually led to his theory on the electronic mechanisms of metal catalysis.
In later years, after returning to Munich as professor of physical chemistry, Schwab discovered the surface catalytic influence of a metal in contact with a semiconductor catalyst or an insulator in contact with a metal catalyst (occasionally referred to as Schwab effects of the 1st and of the 2nd type, respectively).