Sunlight-driven photocatalytic oxidation of 5-hydroxymethylfurfural over a cuprous oxide-anatase heterostructure in aqueous phase

Photocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran in water is an economical and sustainable approach. We report a (Cu2O)x‖TiO2 photocatalyst with p-n heterostructure by chemical reductive precipitation method. This catalyst shows 64.5 mg gcatal.−1 h−1 of DFF production at a yield of 23% under simulated sunlight irradiation in O2 and H2O without any additives. It is the most outstanding result for oxide photocatalysts reported to date. We demonstrate that the content of TiO2 determines the conversion of HMF while the content of Cu2O and the crystalline phase of TiO2 (i.e., anatase and rutile) impact the selectivity of DFF. The optimum strong interaction between Cu2O and TiO2 semiconductors is attained in the (Cu2O)0.16‖TiO2(anatase) photocatalyst. This not only ameliorates the pristine photoelectric property of TiO2 but also promotes the generation of 1O2 species on Cu2O by O2 activation. This work realizes TiO2-based photocatalysis with satisfactory visible-light response toward selective oxidation of HMF.