Synergistic High-Efficiency Photoelectrochemical Water Splitting via Type-II Heterojunction MW:BVO/CeO2 Coupled with Ultrathin NiFeOOH

In order to solve the problem of slow water oxidation kinetics and charge complexation of the BiVO4 photoanode, CeO2 octahedral nanomaterials doped with different amounts of NaH2PO4 (COP3) were synthesized by a hydrothermal method in one step. CeO2-based materials have been widely studied in the fields of organic catalysis, photocatalysis to decompose water, and photodegradation of organic pollutants, showing excellent photocatalytic properties. The heterostructure formed by MW:BVO and COP3 (doped with 0.002 g of NaH2PO4) expands the light absorption range and accelerates the separation of the internal carriers. In order to further improve the photocatalytic performance, the MW:BVO/COP3@NiFeOOH (immersion time of 1 h and pH = 8, respectively) composite was prepared by introducing NiFeOOH. As a metal oxide coating additive, NiFeOOH can rapidly capture holes and effectively use these holes for water oxidation on the photoelectrode surface through a cyclic catalytic process. In addition, MW:BVO/COP3@NiFeOOH nanocomposites can effectively increase the active surface area and accelerate the interfacial charge transfer. The final prepared MW:BVO/COP3@NiFeOOH nanocomposites showed excellent photocurrent density (4.8 mA cm–2 at 1.23 V vs RHE) in LSV tests due to the efficient separation and transfer of photogenerated carriers. It can be seen that the interaction between MW:BVO, COP3, and NiFeOOH not only improves the performance of this new class of materials but also highlights the importance of COP3 as an important component worthy of further study.