Study of the photocatalytic activity of nanomaterials based on potassium polytitanate modified with transition metal ions (Ni2+, Cr3+, Cu2+) demonstrated that the cation composition, morphology of photocatalyst particles, and their size strongly affect the photocatalytic activity. The rate of the photoinduced hydrogen evolution from the aqueous-alcoholic solution grows in the series of potassium polytitanates modified with Cu2+, Ni2+, Cr3+ ions, and that from pure water, for potassium polytitanates modified with Ni2+,Cr3+, Cu2+ ions. The capacity for intercalation of water into the interlayer space does not strongly affect the rate of the photoinduced hydrogen evolution. It was shown that potassium polytitanate modified with Cr3+ ions has the maximum quantum efficiency (30%).