TiO2 hollow spheres with surface-rich Ti3+ under Pd-catalyzed hydrogenation for improved visible-light photocatalysis

摘要

To enhance the utilization of visible light and prevent photogenerated electrons/holes from recombination, black TiO2 hollow spheres of varying shell thicknesses rich in Ti3+ were synthesized via hydrogenation with the aid of Pd. With increasing hydrogenation temperature from room temperature to 200 degrees C, the thickness of the disordered layer increases, and the concentration of Ti3+, which is the main active site for photocatalysis, also increases. Owing to the intense visible-light harvesting nature and rich active sites introduced by the disordered layer, the black TiO2 hollow spheres obtained at 200 degrees C degrade rhodamine B (RhB) to 95.2% within 120min under visible-light illumination. In addition to the role of enhanced visible-light absorbance, Ti3+ also improves the conductivity, which is further confirmed with Li-ion batteries. The enhanced conductivity favors the separation of photogenerated electrons/holes.