Synergetic effect of interface and surface on photocatalytic performance of TiO 2 @ hollow CeO 2 core-shell nanostructures
Résumé
The photocatalytic performance of new TiO 2 /CeO 2 composites is reported and the mechanism for its enhancement with respect to bare TiO 2 and CeO 2 nanoparticles is revealed. With a two-step process, TiO 2 shells were deposited on CeO 2 hollow cores forming the composites (TiO 2 @H-CeO 2). With tuning the shell deposition, optical properties were engineered. The absorption range was extended to visible light and the lifetime of photoinduced electron-hole pairs were prolonged. Photo-degradation experiments indicate that the removing of 10-5 M methylene blue by TiO 2 @H-CeO 2 was improved under both UV and visible light. The highest degradation rate constant K reached 0.023 min − 1 under visible light showing an enhancement of more than one order of magnitude as compared to solely TiO 2 or CeO 2 nanoparticles. High-resolution electron energy loss spectroscopy was utilized to investigate both surface and interface areas. It demonstrates a strong interface interaction between CeO 2 and TiO 2 after forming core-shell structure with the introduction of a nanometrical interface layer and a modification of the Ce 3+ and Ti 3+ content near the interface. The present work revealed that the photocatalytic efficiency can be improved effectively by optimizing the synergistic effect of interface through adjusting the TiO 2 deposition process.
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