The direct formic acid fuel cell is an emerging energy conversion device for which palladium is considered as the state-of-the-art anode catalyst. In this communication, we show that the activity and stability of palladium for formic acid oxidation can be significantly enhanced using nickel phosphide (Ni2P) nanoparticles as a cocatalyst. X-ray photoelectron spectroscopy (XPS) reveals a strong electronic interaction between Ni2P and Pd. A direct formic acid fuel cell incorporating the best Pd-Ni2P anode catalyst exhibits a power density of 550mWcm(-2), which is 3.5times of that of an analogous device using a commercial Pd anode catalyst.