The objective of this work is to verify the feasibility of implementing fractal structuring to reduce the amount of active catalyst surface required in microreactors. This work follows up on the work by Phillips et al. [Chem. Eng. Sci., 2003, 58, 2403-2408], where the authors reported the use of Cantor triads to reduce the total amount of active catalyst in a mass-transfer-limited system. They considered flat-plate geometry with infinitely fast reactions. This work is extended to realistic microreactors with finite rate chemistry to study the effect of catalyst structuring in the presence of flow confinement. Fractal and periodic patterns are formed by removing the catalyst from various sections along the reactor wall, resulting in alternating catalytic and noncatalytic segments. Two-dimensional computational fluid dynamics (CFD) simulations of tubular microreactor channel with catalyst structuring are performed. Our results show that the role of catalyst structuring confined geometry is rather modest, compared to the open (flat-plate) geometries considered so far. We also show that singularities (boundary of noncatalytic and catalytic segments) formed with catalyst structuring, and not the fractal pattern itself, are responsible for improved conversion from the microreactor. Large gradients at singularities result in enhanced mass transfer, which is analyzed using Sherwood number correlations. The effect of various operating parameters is investigated. © 2011 American Chemical Society.