Synergistic coupling of surface plasmon resonance with metal-organic frameworks based biomimetic Z-Scheme catalyst for enhanced photoelectrochemical water splitting.

[Display omitted] • A plasmonic Z-scheme catalyst (TiO 2 /NH 2 -MIL-125/Au) was designed and constructed. • The Z-scheme architecture endowed TiO 2 /NH 2 -MIL-125/Au with stronger redox capability. • The surface plasmon resonance of AuNPs improved the charge separation of the catalyst. • A remarkably improved photocurrent density for TiO 2 /NH 2 -MIL-125/Au has been achieved. Developing and nano-engineering of photoanodes with high solar energy utilization and charge separation efficiency is urgently desirable in photoelectrochemical (PEC) water splitting for renewable energy sources. Herein, a novel synergistic coupling catalyst (TiO 2 /NH 2 -MIL-125/Au) is constructed by integrating MOFs-based Z-scheme catalysts with the surface plasmon resonance (SPR) of gold nanoparticles (AuNPs). The electron paramagnetic resonance (EPR) spectra and theoretical calculation indicate that the charge transfer path follows the Z-scheme principle and the SPR effect of AuNPs remarkably enhances the electromagnetic (EM) field at the coupling region acting as hot spots. Such superiority in physical structures endows TiO 2 / NH 2 -MIL-125/Au with stronger redox capability and improved charge separation efficiency. Correspondingly, the plasmon coupled Z-scheme catalyst exhibits excellent PEC performance with a 2.2-fold enhancement in comparison with the pristine TiO 2 nanotube arrays. This work develops a novel synergistic coupling model by integrating the plasmonic effect with biomimetic Z-scheme systems and sheds light on a deep understanding of plasmon-enhanced Z-scheme catalysts. [ABSTRACT FROM AUTHOR]