Ammonia decomposition in catalytic membrane reactors consisting a SiO2 separation layer and Ru/γ-Al2O3/α-Al2O3 catalysts in one unit was proposed for COx-free hydrogen production in this study.The catalytic membranes showed a H2 permeance of~6.2× 10-7 mol Pa-1 m-2 s-1 at 500 ℃, with H2/NH3 and H2/N2 selectivities of 200 and 720, respectively.Ammonia conversion was surprisingly enhanced form 45% to 95% at 450 ℃ after selective H2 extraction.