A coating technique based on the deposition–precipitation of aluminium hydroxide from supersaturated aluminate solutions was applied to the preparation of catalyst supports for application in a glass microreactor. The porous alumina layer obtained after calcination of the deposited hydroxide was characterised by BET, SEM and XRD techniques. Pt/Al 2 O 3 catalysts were prepared using the deposited porous alumina as support. The microreactor coating obtained demonstrated the adhesion to the glass substrate compatible with liquid/liquid liquid/gas application and good compatibility with the complex microreactor shape. The phase composition and specific surface area of the coating are very similar to a more conventional powdered γ-alumina catalyst support.