Carbonized Polymer Dots/Bi/β-BiO for Efficient Photosynthesis of HO via Redox Dual Pathways.

A novel heterojunction photocatalyst of carbonized polymer dots (CPDs)/Bi/β-BiO is successfully synthesized via a one-pot solvothermal method by adjusting the reaction temperature and time. As a solvent and carbon source, ethylene glycol not only supports the conversion of Bi to β-BiO but also undergoes its polymerization, cross-linking, and carbonization to produce CPDs. In addition, partial Bi is reduced to Bi by ethylene glycol. As a result, the CPDs and Bi are deposited in situ on the surface of β-BiO microspheres. There are four built-in electric fields in the CPDs/Bi/β-BiO system, namely, the n-type semiconductor β-BiO/HO interface, the p-type CPDs/HO interface, the ohmic contact between Bi and β-BiO, and the Schottky junction between Bi and CPDs. Under the action of four built-in electric fields, the Z-type charge separation mechanism is formed. It promotes the effective separation of the photogenerated electron-hole and greatly improves the yield of HO. Under irradiation for 2 h, the HO production is 1590 μmol g h. The solar energy to HO conversion efficiency is 0.11%.