The electrocatalytic properties of platinum microparticles incorporated into poly-(vinylpyridine) (PVP) films, a conducting polymer with good conductivity and stability, were investigated for hydrogen evolution and formic acid electrooxidation in acidic media. It wasfound that the catalytic effects depend mainly on the size and amounts of the platinummicroparticles dispersed in the polymer layer. The electrocatalytic properties of platinum microparticles incorporated into poly- (vinylpyridine) (PVP) films, a conducting polymer with good conductivity and stability, were investigated for hydrogen evolution and formic acid electrooxidation in acidic media. It wasfound that the catalytic effects depend mainly on the size and amounts of the platinummicroparticles dispersed in the polymer layer.