With the method he analysed the surface composition of atmospheric salt aerosol particles and contributed to the current climate model.

In 1997 he left to build up a new activity on microprocess engineering, with a focus on heterogeneous catalysis in microchannels, for fuel processing (methanol steam reforming, partial oxidation of methane) and synthesis of chemicals.

In 2000 he was offered a position at the new Institute of Nanotechnology, INT[2] (Founding directors: Herbert Gleiter, Jean-Marie-Lehn, Dieter Fenske) to build up a new activity on nanoscale materials for energy storage.

[4] In his career Fichtner worked on various topics, covering Theoretical Chemistry, Instrumental Analysis, Higher Administration, Chemical Engineering, Heterogeneous Catalysis, Hydrogen Storage, Electrochemistry and Battery Research.

Pioneering achievements were the first measurements of salts with Secondary Neutral Mass Spectrometry,[5] the development of a depth-resolved speciation of beam sensitive salts, a microstructure reactor which could safely burn and transfer the heat from a stoichiometric hydrogen-oxygen mixture to a thermo oil, thus demonstrating the enormous capability of running dangerous reactions in microstructure reactors safely.