Chlorophyll-modified Au25(SR)18-functionalized TiO2 for photocatalytic degradation of rhodamine B

Solar-driven photocatalysis is a promising route toward cleaner production using sunlight as a sustainable energy source. Nanocrystalline TiO2, in the form of mixed anatase/rutile phases (P25), is often employed, but must be modified for higher activity in visible light. To improve the light harvesting properties, nano-bio hybrid photocatalysts were prepared by functionalizing P25 with Au-25 clusters, Au nanoparticles, and/or chlorophyll. The most effective photocatalytic degradation of rhodamine B (RhB) was observed over P25 catalysts functionalized with both Au-25 and chlorophyll. HR-TEM, UV-vis, XPS and XANES/EXAFS were applied to examine the factors influencing photocatalytic activity. A direct contact between Au-25, chlorophyll, and P25, strongly improved the electron transfer from chlorophyll to P25, while still maintaining the reusability of catalysts. For chlorophyllmodified Au-25(SR)18-functionalized P25 catalyst, the degradation rate of RhB was enhanced similar to 16 times compared to that of P25.

Automated summary

Solar-driven photocatalysis is a promising approach for clean production using sunlight as an energy source. The efficiency of nanocrystalline TiO2 catalysts can be improved by functionalizing them with Au-25 clusters, Au nanoparticles, and chlorophyll. The most effective degradation of rhodamine B was achieved using a P25 catalyst functionalized with both Au-25 and chlorophyll. Various characterization techniques were used to investigate the factors influencing the photocatalytic activity.