Catalytic-aided combustion is a proven technique for burning highly lean and ultra-lean mixtures of hydrogen and air. However, the noble catalyst required for combustion is naturally scarce and therefore expensive. In this study, we focus on a numerical investigation to determine the best way of coating a platinum catalyst inside a catalytic hydrogen reactor. We study various planar and non-planar reactors and find that the reactor with a combination of half and full cylinders is the most effective in H2 conversion. Compared to an equivalent catalytic planar reactor, the non-planar configuration increases the H2 conversion by 30.7 %. The results show that enhancing mass and heat convection can significantly increase the H2 conversion. Furthermore, in a non-planar reactor, surfaces with enhanced mass and heat transfer can achieve up to 50 % catalyst savings when coated with a catalyst, while still maintaining a conversion rate of 2 kg/s per unit of catalytically-coated surface area.