A tiny amount of Pt was deposited in a quasi-two-dimensional form onto the nanoporous gold (NPG) substrate through a simple immersion-electrodeposition (IE) method, forming nanostructured bimetallic Pt-Au catalysts. Such Pt-Au nanostructures have much higher structural stability than the bare NPG; moreover, they exhibit better catalytic activity and stronger poison resistance than commercial Pt-Ru catalysts because of the synergistic effect of the bimetallic compositions.