Direct and Efficient Synthesis of Clean H2O2 from CO-Assisted Aqueous O2 Reduction

Development of efficient and affordable catalytic systems for direct H2O2 production from abundant resources is necessary to replace the current anthraquinone process and also to enable broader use of H2O2 for clean oxidations. A prospective route for directly obtaining H2O2 is aqueous reduction of O2 using carbon monoxide (CO) as a reducing agent. However, homogeneous catalysts reported in the literature typically lack the required level of performance in mild ligand- and additive-free conditions. Here, we demonstrate that gold nanoparticles supported on titania (Au/TiO2), which is a well-known catalyst for CO oxidation at subambient temperature, can catalyze the formation of H2O2 from the reaction of CO and O2 in aqueous solution at ambient temperature and pressure conditions. We show that, benefiting from the intrinsic CO/H2O-induced Au–H formation capability of the Au–TiO2 interface, this hitherto unappreciated system can deliver up to 9097 mmolH2O2 gAu–1 h–1 efficiency for direct and stable H2O2 production. In addition to the high productivity, a more relevant performance was demonstrated in the vacuum distillative processing of the diluted H2O2-containing streams to furnish a range of pure H2O2 solutions up to 32 wt %. The practical and straightforward application of this H2O2-generating system provides an expedient and efficient entry to establish a sequential tandem process where CO is initially converted to H2O2 and H2O2 subsequently serves as a benign oxidant for selective oxyfunctionalization of aromatic hydrocarbons.