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‐NH 2 , denoted as Pt@UiO‐66‐NH 2 and Pt/UiO‐66‐NH 2 , 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‐NH 2 greatly shortens the electron‐transport distance, which favors the electron–hole separation and thereby yields much higher efficiency than Pt/UiO‐66‐NH 2 . The involved mechanism has been further unveiled by means of ultrafast transient absorption and photoluminescence spectroscopy.