Selective Anthracene Photooxidation over Titania-supported Single Atom Catalysts

Single-atom catalysts (SACs) often show exceptionally high performance per metal loading. Besides benefiting from a better atom utilisation, the metal-support interaction is more pronounced in SACs compared to traditional nanoparticle catalysts. Thus, using SACs in photochemical conversions is of great advantage where the rapid reactions often depend on the synergistic interaction of the active site with the photoactive support. Here we show the importance of this interaction by maximizing the active site/support interface using SACs. As an example, we examine the oxidation reaction of anthracene to anthracene-9,10-endoperoxide (EPO) in the presence of 0.1 wt% Pt/TiO2. Our SACs give a six-fold improvement compared to dense packed nanoparticle catalysts (TOF=113 mMol Anthracene gPt-1 min--1 for the SAC). We attribute this to the synergy between the active site and the support. Moreover, we show that photocatalytic conversion is possible with photons of lower energy (2.7 eV) than the bandgap of pristine TiO2 (Eg=3.0-3.2 eV) thanks to organic doping of the metal oxide. Dim the lights: Single-atom Pt/TiO2 sites catalyse the photooxidation of anthracene even below the titania band gap.image