As a novel approach to simultaneous water gas shift (WGS) reaction and separation for the production of hydrogen, a bi-functional membrane was successfully prepared using a simple coating method. The catalyst materials, Pt and CeO2, were directly coated over the surface of a Pd-Au dense membrane for excluding slow hydrogen diffusion through the conventional catalyst bed. The coated catalyst layer did not significantly affect the hydrogen permeance of the bare membrane, due to the presence of metal within the catalyst compositions which acted as a bridge for the surface diffusion of hydrogen atoms. As a result of WGS reaction within the novel membrane reactor at 380 degrees C, the CO conversion was 2 times higher than that of no hydrogen separation. The catalyst-deposited membrane can make the "simultaneous chemical reaction and separation" more feasible and relatively simple, if the more robust catalysts can be loaded with the increased active surface area and the multi-membrane module reactor adopted the coin-shape bi-functional membranes can be designed to completely treat the CO and separate hydrogen from the CO mixture. Crown Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.