Synergetic effect of interface and surface on photocatalytic performance of TiO2@ hollow CeO2 core–shell nanostructures

Abstract The photocatalytic performance of new TiO2/CeO2 composites is reported and the mechanism for its enhancement with respect to bare TiO2 and CeO2 nanoparticles is revealed. With a two- step process, TiO2 shells were deposited on CeO2 hollow cores forming the composites (TiO2@H-CeO2). With tuning the shell deposition, optical properties were engineered. The absorption range was extended to visible light and the lifetime of photo-induced electron-hole pairs were prolonged. Photo-degradation experiments indicate that the removing of 10-5 M methylene blue by TiO2@H-CeO2 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 TiO2 or CeO2 nanoparticles. High-resolution electron energy loss spectroscopy was utilized to investigate both surface and interface areas. It demonstrates a strong interface interaction between CeO2 and TiO2 after forming core–shell structure with the introduction of a nanometrical interface layer and a modification of the Ce3+ and Ti3+ 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 TiO2 deposition process.