Photocatalysis has shown great potential as a green technology to help solve the energy shortage and environmental pollution issues. In particular, TiO₂ has attracted a great deal of attention as a representative photocatalytic material due to its chemical inertness, strong oxidizing activity, long-term stability against photocorrosion and chemical corrosion, cost-effectiveness, and non-toxicity.^1,2  However, TiO₂ possesses a wide band gap (3.0–3.2 eV) that limits its photo-absorption to the UV region, which accounts for only about 4% of the total irradiated sunlight. From the perspective of practical applications, it is highly desirable to develop new photocatalytic materials that harvest photons over a wide range of visible wavelengths or even into the infrared region.