Location Effect in a Photocatalytic Hybrid System of Metal-Organic Framework Interfaced with Semiconductor Nanoparticles

We report an ultrafast spectroscopy investigation that addresses the subtle location effect in a prototypical semiconductor-MOF hybrid system with TiObegin{document}$_2$end{document} nanoparticles being incorporated inside or supported onto Cubegin{document}$_3$end{document}(BTC)begin{document}$_2$end{document}, denoted as TiObegin{document}$_2$end{document}@Cubegin{document}$_3$end{document}(BTC)begin{document}$_2$end{document} and TiObegin{document}$_2$end{document}/Cubegin{document}$_3$end{document}(BTC)begin{document}$_2$end{document}, respectively. By tracking in real time the interface electron dynamics in the hybrid system, we find that the interface states formed between TiObegin{document}$_2$end{document} and Cubegin{document}$_3$end{document}(BTC)begin{document}$_2$end{document} can act as an effective relay for electron transfer, whose efficiency rests on the relative location of the two components. It is such a subtle location effect that brings on difference in photocatalytic CObegin{document}$_2$end{document} reduction using the two semiconductor-MOF hybrids. The mechanistic understanding of the involved interface electron-transfer behavior and effect opens a helpful perspective for rational design of MOF-based hybrid systems for photoelectrochemical applications.