Ternary Co-Pi-Ag/TiON photocatalysts were designed and fabricated by a facile precipitation and electrochemical strategy. The results showed the superiority of the Co-Pi-Ag/TiON as a promising photoanode for photoelectrochemical water oxidation. In comparison with Co-Pi-Ag/TiO2, Ag/TiON, and Ag/TiO2 photoanodes, the Co-Pi-Ag/TiON showed a significant photocurrent density of 5.5 mA cm(-2) at 1.0 V vs Ag/AgCl, which is 10-fold that of bare TiO2. The extraordinary performance can be ascribed to the synergy between nitrogen doping, Co-Pi functionalization, Ag loading, and the unique structural features of the synthesized photoelectrodes. This was further confirmed via the exceptionally high hydrogen generation rate of the Co-Pi-Ag/TiON ternary catalyst (54 mu L h(-1) cm(-2)), which is much higher than that reported for most of the TiO2-based photocatalysts.