Boosting Photocatalytic Hydrogen Production of a Metal-Organic Framework Decorated with Platinum Nanoparticles: The Platinum Location Matters

Improving the efficiency of electron-hole separation and charge-carrier utilization plays a central role in photocatalysis. Herein, Pt nanoparticles of ca. 3 nm are incorporated inside or supported on a representative metal-organic framework (MOF), UiO-66-NH2, denoted as Pt@UiO-66-NH2 and Pt/UiO-66-NH2, respectively, for photocatalytic hydrogen production via water splitting. Compared with the pristine MOF, both Pt-decorated MOF nanocomposites exhibit significantly improved yet distinctly different hydrogen-production activities, highlighting that the photocatalytic efficiency strongly correlates with the Pt location relative to the MOF. The Pt@UiO-66-NH2 greatly shortens the electron-transport distance, which favors the electron-hole separation and thereby yields much higher efficiency than Pt/UiO-66-NH2. The involved mechanism has been further unveiled by means of ultrafast transient absorption and photoluminescence spectroscopy.