Highly selective photocatalytic oxidation of 5-hydroxymethylfurfural by interfacial Pt-O bonding Pt-Ov-BiOBr

The photocatalytic oxidation of 5-hydroxymethylfurfural (HMF) has the advantages of mild conditions and a controllable oxidation degree. There are a number of methods to increase its reactivity by boosting the production of O-2(-), among which using metal-modified semiconductor catalyst systems is one of the most promising methods. Although several metal-modified semiconductor catalyst systems have been successfully designed, only a small number of them have been used in photocatalytic selective oxidation, and the contact interface between the metal and semiconductor catalysts has not been well studied. Here, interfacial Pt-O bonded Pt-Ov-BiOBr catalysts were designed for photocatalytic HMF selective oxidation. Due to the environment of unsaturated coordination on Ov-BiOBr, Pt can form a Pt-O bond as an electron transport channel to transfer photogenerated electrons from Ov-BiOBr to Pt for efficient generation of O-2(-). Meanwhile, photogenerated h(+) will gather at the interface between Pt and Ov-BiOBr contact to oxidize HMF to carbon-centered radicals. The spatial proximity of the O-2(-) and carbon-centered radicals at the Pt-Ov-BiOBr contact interface promotes reciprocal collisions and consequently reactions. Additionally, Pt-Ov-BiOBr was found to have excellent photogenerated electron-hole separation efficiency by photoelectric characterization, and the ESR and O-2-TPD results showed that Pt can activate oxygen more effectively to produce O-2(-). As a result, the conversion rate of HMF selective oxidation of Pt-Ov-BiOBr becomes 4.6 times higher and the selectivity becomes 2.2 times higher compared to those of BiOBr. This study suggests that an appropriately designed metal-semiconductor contact interface can boost the effectiveness of HMF photocatalytic selective oxidation.