Tailored Cl– Ligation on Supported Pt Catalysts for Selective Primary C–H Bond Oxidation

It is challenging to achieve high selectivity over Pt-metal-oxide catalysts widely used in many selective oxidation reactions because Pt is prone to over-oxidize substrates. Herein, our sound strategy for enhancing the selectivity is to saturate the under-coordinated single Pt atoms with Cl– ligands. In this system, the weak electronic metal–support interactions between Pt atoms and reduced TiO2 cause electron extraction from Pt to Cl– ligands, resulting in strong Pt–Cl bonds. Therefore, the two-coordinate single Pt atoms adopt a four-coordinate configuration and thus inactivated, thereby inhibiting the over-oxidation of toluene over Pt sites. The selectivity for the primary C–H bond oxidation products of toluene was increased from 50.1 to 100%. Meanwhile, the abundant active Ti3+ sites were stabilized in reduced TiO2 by Pt atoms, leading to a rising yield of the primary C–H oxidation products of 249.8 mmol gcat–1. The reported strategy holds great promise for selective oxidation with enhanced selectivity.