Published online by Cambridge University Press: 11 July 2012
We confirmed that GaN photocatalyst with NiO cocatalyst (GaN-NiO) continuously produced hydrogen from water for 500 hours without any extra bias. The GaN-NiO photocatalyst was hardly etched and 184-mL hydrogen gas was produced from the electric charge of 1612 coulombs, the Faradic efficiency of which was 89.2%. The conversion efficiency from incident light energy to hydrogen chemical energy was 0.98% in average for 500 h. The incident photon-to-current conversion efficiency (IPCE) was 50% at 300 nm and 35% at 350 nm after the experiment, which was much higher than those of other semiconductor-based photocatalysts.