Efficient visible-light photocatalytic degradation system assisted by conventional Pd catalysis

Different approaches like doping and sensitization have been used to develop photocatalysts that can lead to high reactivity under visible-light illumination, which would allow efficient utilization of solar irradiation and even interior lighting. We demonstrated a conceptually different approach by changing reaction route via introducing the idea of conventional Pd catalysis used in cross-coupling reactions into photocatalysis. The -O-Pd-Cl surface species modified on Ni-doped TiO2 can play a role the same as that in chemical catalysis, resulting in remarkably enhanced photocatalytic activity under visible-light irradiation. For instance, Pd/Ni-TiO2 has much higher activity than N-TiO2 (about 3 ~ 9 times for all of the 4-XP systems) upon irradiation with wavelength of 420 nm. The catalytically active Pd(0) is achieved by reduction of photogenerated electrons from Ni-TiO2. Given high efficient, stable Pd catalysts or other suitable chemical catalysts, this concept may enable realization of the practical applications of photocatalysis.