Pd-Ag alloy membranes (0.4 mu m) have been prepared on porous TiO2/Al2O3 support via a photocatalytic co-deposition technique. Using this technique the membrane composition can be precisely controlled and the alloying of Pd-Ag carried out more easily. X-ray diffraction and scanning electronic microscopy analysis of the Pd-Ag composite membranes indicated that the metal existed in the form of alloy and membrane surface appeared homogeneous. A gas permeation experiment was conducted under temperature of 693 K and pressure of 0.01-0.06 MPa. Hydrogen permeance and selectivity of hydrogen/nitrogen (H-2/N-2) were 1 x 10(-5) Mol m(-2) s(-1) Pa-1 and 7.1-7.4, respectively. (c) 2008 Elsevier B.V. All rights reserved.