In-situ implantation of plasmonic Ag into metal-organic frameworks for constructing efficient Ag/NH2-MIL-125/TiO2 photoanode

Realizing a highly efficient catalytic activity for photoelectrochemical (PEC) water splitting has been becoming a key challenge for fabricating TiO 2 photoanode, due to its weak light-response ability and poor electrical conductivity. For the first time, we prepared the TiO 2 nanorods decorated with NH 2 -MIL-125 film, and subsequently in-situ implanted Ag nanoparticles (Ag NPs) into NH 2 -MIL-125 film by mild reduction process with the help of amine group. The synergistic effect between NH 2 -MIL-125 and Ag NPs is aimed at efficiently improving light-response and the overall conductivity of photoanode. The PEC performance of as-prepared Ag/NH 2 -MIL-125/TiO 2 hybrid-photoanode has been systemically investigated. The photocurrent density of optimal Ag/NH 2 -MIL-125/TiO 2 has reached 1.06 mA/cm 2 at 1.23 V (vs. RHE) under illumination (100 mW/cm 2 ), which is almost 4.42 times higher than that of pristine TiO 2 . The incident photon-to-electron conversion efficiency (IPCE) value of Ag/NH 2 -MIL-125/TiO 2 has been increased to 51.0% at 390 nm. Furthermore, the desirable charge injection ( η i n j e c t i o n ) of 96.4% and charge separation ( η s e p a r a t i o n ) efficiency of 33.1% have been achieved. The in-situ introduction of Ag NPs into NH 2 -MIL-125/TiO 2 heterostructure provides a novel model for understanding the synergistic effect between metal and MOF over PEC water splitting.