Microreactors are promising for fine chemistry and value-added chemical synthesis, but the small dimension places significant challenges in catalyst layer fabrication. Meanwhile, enhancing catalyst dispersion to obtain smaller particle size are of great interests. We proposed a multilayered Pd nanocatalysts with nano-bulge structure inside a microreactor for multiphase catalytic reaction. The unique bulged nanostructure can provide more accessible sites for precursor (PdC1 4 2) adsorption, and extend the available area to reduce the Pd nanoparticle size. Experimental results show rugged Pd catalyst layer with the nanobulge structure was prepared, and both the precursor utilization rate and Pd nanocatalysts dispersion were enhanced, resulting in 35.4% higher catalyst loading and 4-fold smaller particle size. Benefitting from these advantages, compared with conventional Pd coated polydopamine catalyst layer, the proposed multilayered Pd nanocatalyst can significantly intensify the reaction rate and obtain an order of magnitude longer durability in nitrobenzene hydrogenation. This versatile and convenient fabrication method can be used in fabricating high performance and durable catalyst layers in microreactors. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.