Synthesis, characterization and performance evaluation of a novel flower-like Zn Zr MOF/FeWO4/BiOBr/Ti photoanode with type II heterojunction and visible light response

The performance of a photocatalytic fuel cell (PFC) depends on its photoelectrode. In this work, a novel three-dimensional flower-like hierarchical photoanode Zn-Zr MOF/FeWO4/BiOBr/Ti was synthesized, characterized and applied in PFC to degrade rhodamine B and generate electricity simultaneously. The characterization results of XRD, SEM, EDS, FI-IR, DRS, and XPS show that the photoanode was successfully prepared. The loading of FeWO4 and Zn-Zr MOF widened the nanosheet spacing of BiOBr, which enhanced the light absorption intensity, broadened the light absorption band edge from 467.6 nm to 490.2 nm, and increased the photocurrent density from 0.0149 mA/cm2 to 0.156 mA/cm2. The maximum photocurrent density, maximum power density, degradation rate, and FF of the PFC with the prepared photoanode were respectively 0.256 mA·cm-2, 22.65 μW·cm-290.48% (1h), and 0.216, which were far higher than those of PFCs with mono and binary photoanodes. The strong photocatalytic performance of the photoanode is attributed to the type II heterojunction formed between BiOBr and FeWO4, which helps to separate electron-hole pairs. The main reactive materials responsible for degrading rhodamine B are h+ and ·O2-. This research provides a new idea for developing an efficient visible light response photoanode.