A visible light induced, highly oxidative, and highly reductive photocatalyst. The photocatalyst includes a first semiconductor with a bandgap between valence band and conduction band thereof between 2.0 eV and 3.0 eV, and second semiconductor, combined with the first semiconductor, with a bandgap between valence band and conduction band thereof between 2.0 eV and 3.0 eV. The conduction band of the first semiconductor is negative relative to that of H.sub.2/H.sub.2O with a difference of 0.2 eV or greater. The valence band of the second semiconductor is positive relative to that of H.sub.2/H.sub.2O with a difference of 2.8 eV or greater.