From the carried out experiments, it is evident that the µReactor offers significant advantages for in-situ studies of heterogeneous reactions and vacuum annealing. Its small volume facilitates clear observations under pressure, which enhances safety, preserves the microscope's technical condition, and optimizes gas consumption. Chemically speaking, the reductive growth of W18O49 nanowhiskers is more efficient when using hydrogen as a reducing agent. Compared to vacuum annealing, the nanowhiskers exhibit a higher aspect ratio, and the reaction allows for more controlled nanofibrous morphology. In both scenarios described above, the W18O49 nanowhiskers formed bundled structures protruding from the nanofibrous backbone. In the follow-up experiment the W18O49 nanowhiskers were produced and visualized via in-situ W18O49 growth experiments in the TEM using MEMS chip for sample heating and direct observation through a SiN membrane.