Synergy of palladium species and hydrogenation for enhanced photocatalytic activity of {001} facets dominant TiO_2 nanosheets

摘要

{001} facets dominant TiO_2 nanosheets have attracted intensive attention in the photocatalytic field, due to their undercoordinated Ti_(5c) centers, higher surface energy, and photocatalytic activity than those of any other low-energy facet. However, a fluorine-rich (001) surface is controversial to the photocatalytic activity of TiO_2 nanocrystals. We have removed the surface F atoms bonding with Ti by hydrogenation method successfully, and found that {001} facets dominant TiO_2 nanosheets without the terminated F atoms showed dramatic enhancement in the photocatalytic activity. Moreover, the clean (001) surface was more in favor of the deposition of PdO than the fluorine-rich surface, and the amorphous structure from the hydrogenation is beneficial to the reduction of PdCl_4~(2-) to Pd nanoparticles. The PdO attached on {001} facets and the amorphous structure promoted the separation of charge carriers, and Pd nanoparticles transferred plasmonic-induced electrons to the conduction band of hydrogenated TiO_2 under simulated solar irradiation. Thus, a significantly enhanced photocatalytic activity of Pd-H-TiO_2 is achieved on degrading organic environmental pollution, due to the synergy of palladium species and hydrogenation on {001} facets exposed TiO_2.