The SERS Study Of V-O Aggregation State In Homogeneous And Heterogeneous Systems

In this work, SERS of V-O species in water solution and V2O5/TiO2 catalysts were studied respectively. By means of DFT calculation, NH3-TPD, H2-TPR, XRD, TEM, XPS and i-propanol oxidation/dehydration reaction test, the V-O aggregation state, the redox and acid properties in homogeneous and heterogeneous systems were studied. It was found that, the Raman spectroscopy of V-O species in water solution could be enhanced by silver mirror and gold nanoparticles. The V-O species converted from V2O74- to V3O93- and V10O286-, with the decreasing of pH 11.o to 6.3. This was coincide with results from other methods, but the Raman peak intensity enhanced 1×106 times. The raman spectroscopy of surface V-O species on 2%wt V2O5/TiO2 catalyst was obtained by SERS method. With the increment of V-O polymerization in precursor, surface V-O species polymerization degree increased, the reducibility decreased, and the oxidative dehydrogenation activity decreased. And its acidity increased which lead to the increasing of i-propanol dehydration activity. So SERS would be an effective method to study 1 V-O aggregation state in very low loadings.