Control synthesis of self-standing porous bimetallic nanosheet array is of significant importance for electrocatalytic applications. Herein, we report an in-situ approach for directly fabricating interweaved porous palladium-ruthenium nanosheets on Ni foam (PdRu NS-NF) via a micelle-assisted galvanic replacement reaction using Ni foam as both the reductant and substrate. These nanosheets possess interconnected porosity and bimetallic compositions, which provide abundant active sites and strong electronic effect. The binder-free PdRu NS-NF shows outstanding activity and stability for electrocatalytic nitrogen reduction to ammonia. Different from traditional complex methods for the fabrication of metallic nanosheets, the proposed approach is very feasible to directly synthesize metallic array with tunable morphology and composition on three-dimensional metallic substrates. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.