V ion-implanted titanium oxide

Figure 10 Effect of the depth profile of V ions in the V-ion-implanted titanium oxide photocatalyst on their photocatalytic reactivity for the decomposition of NOx under visible light (X > 450 nm) irradiation at 295 K.

The ESR spectra of the V-ion-implanted titanium oxide catalysts were measured before and after calcination of the samples in O2 at around 723-823 K, respectively (Fig. 11). Distinct and characteristic reticular V" ions were detected only after calcination at around 723-823 K. It was found that only when a shift in the absorption band toward visible-light regions was observed, the reticular V ions could be detected by ESR. No such reticular V ions or shift in the absorption band have ever been observed with titanium oxides chemically doped with V ions [16,18,19]. 

Figure 11 Effect of calcination temperature of the V-ion-implanted titanium oxide sample on the ESR spectra of + species in the V-ion-implanted titanium oxide photocatalyst at 77 K.

Other surface analytical techniques, such as x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and secondary ion mass spectroscopy (SIMS) have been utilized to show that the elements of the titanium alloys are present in their surface oxides [78]. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) studies showed that the oxides of the Ti-6Al-4 V alloy have a more complex microstructure and a different crystallinity, which are properties that could affect the biocompatibility of these titanium alloy implants. 

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