In 1931 he received habilitation on graphite oxide[4][5] and then worked as a lecturer at Technische Universität Berlin.
In 1942, he became head of the Institute for Inorganic and Analytical Chemistry at the Vienna University of Technology, where he also installed an electron microscope by Manfred von Ardenne.
[1] Hofmann's research dealt in particular with the chemistry of clay minerals, as well as with pigments and ancient ceramics.
Together with Kurd Endell, he also found the reason why German bentonites, in contrast to those from Wyoming in the USA, were not suitable for the construction industry - the cation between the silicate layers was sodium in American bentonite, and calcium or magnesium in German deposits.
Hofmann also examined other clays (such as kaolin) to see how the properties (e.g., swelling behavior) changed with the cations between the silicate layers when absorbing water.