The controlled synthesis of supported Pt nanoparticles with well‐defined sizes in the range from 1.9 to 6.0 nm and their application in the dehydrogenation of cyclic liquid organic hydrogen carrier (LOHC) molecules are demonstrated. For this purpose, a colloidal approach with a stabilized Pt precursor solution including chemical reduction with aqueous solutions of sodium borohydride (NaBH4) is used. Various synthesis parameters are varied and their effects on the properties of the Pt nanoparticles are studied. Additionally, the nanoparticles were supported on Al2O3 powder and the general suitability of the catalysts for the dehydrogenation of the LOHC perhydro benzyltoluene (H12‐BT) is demonstrated. The synthesis is then transferred from powder to shaped supports. Moreover, upscaling of the synthesis procedure to 50 g of well‐defined catalyst is realized without significant deviations in nanoparticle size but at the expense of a certain activity loss. Finally, a continuous synthesis of Pt/Al2O3 catalysts is implemented using a microfluidic reactor. The small‐scale, large‐scale, and continuous synthesis routes enable the preparation of defined catalysts resulting in a comparable Pt‐based productivity in the dehydrogenation of H12‑BT.
