Low-Temperature Microwave-Assisted Hydrothermal Synthesis of Pb₂Ti₂O_5.4F_1.2 Photocatalyst for Improved H₂ Evolution under Visible Light

Mixed-anion compounds are promising candidates as visible-light-driven photocatalysts; however, their synthesis is generally difficult compared to that of their ordinary single-anion counterparts such as oxides. This difficulty is often an obstacle in maximizing the performance of mixed-anion photocatalysts. In this work, Pb2Ti2O5.4F1.2 particles having a well-defined octahedral shape were successfully synthesized by a microwave-assisted hydrothermal (MHT) method at 473 K. The MHT-Pb2Ti2O5.4F1.2 exhibited a greater specific surface area and improved hydrophilicity compared with its analogue synthesized by a conventional solid-state reaction (SSR). Compared with the SSR-Pb2Ti2O5.4F1.2, the MHT-Pb2Ti2O5.4F1.2 exhibited 6-fold greater activity toward visible-light H2 evolution from water. A postheating treatment of the MHT-derived material in air at 573 K further improved its activity 3–4 fold. The optimized MHT-Pb2Ti2O5.4F1.2 also achieved a nonsacrificial H2 evolution in the presence of a reversible electron donor.