A highly active nano-micro hybrid derived from Cu-bridged TiO2/porphyrin for enhanced photocatalytic hydrogen production

Development of photocatalysts with high activity and durability for hydrogen generation is extremely desired but still remains a great challenge currently. With Cu nanoparticles (Cu NPs) as a linker between TiO 2 microsphere (TiO 2 MS) and 5, 10, 15, 20- meso -tetra(4-carboxyphenyl)porphyrin (TCPP), a novel nano-micro hybrid (TiO 2 MS-Cu-TCPP) was prepared via a facile method. By bridging TiO 2 MS and TCPP with Cu NPs, the absorption and the electron transfer of TiO 2 MS were greatly improved. When the TiO 2 MS-Cu-TCPP was employed as the photocatalyst for hydrogen evolution, it exhibited higher activity and stability than those of the TiO 2 MS, the TiO 2 MS-Cu and the TiO 2 MS-TCPP, TiO 2 MS-Cu-CuTCPP and TiO 2 MS-TCPP-Cu. The photocatalytic activity was enhanced for about 6 times with respect to that of the pristine TiO 2 MS. The excellent performance for the nano-micro hybrid can be attributed to wide light absorption, more reactive sites, and facilitated interfacial electron transfer owing to the strong interaction between TiO 2 and TCPP with Cu NPs as the linker and cocatalyst. Subsequently, a high and stable photocatalytic activity over the TiO 2 MS-Cu-TCPP nano-micro hybrid was achieved, demonstrating the importance of interfacial modification to a semiconductor photocatalyst. This result gives us a new perspective of constructing special structures for efficient light utilization and electron transfer.