Preparation of Y3+-doped Bi2MoO6 nanosheets for improved visible-light photocatalytic activity: Increased specific surface area, oxygen vacancy formation and efficient carrier separation

Although Bi₂MoO₆ (BMO) has recently received extensive attention, its visible-light photocatalytic activity remains poor due to its limited photoresponse range and low charge separation efficiency. In this work, a series of visible-light-driven Y³⁺-doped BMO (Y-BMO) photocatalysts were synthesized via a hydrothermal method. Degradation experiments on Rhodamine B and Congo red organic pollutants revealed that the optimal degradation rates of Y-BMO were 4.3 and 5.3 times those of pure BMO, respectively. The degradation efficiency of Y-BMO did not significantly decrease after four cycle experiments. As a result of Y³⁺ doping, the crystal structure of BMO changed from a thick layer structure to a thin flower-like structure with an increased specific surface area. X-ray photoelectron spectroscopy showed the presence of high-intensity peaks for the O 1s orbital at 531.01 and 530.06 eV, confirming the formation of oxygen vacancies in Y-BMO. Photoluminescence (PL) and electrochemical impedance spectroscopy measurements revealed that the PL intensity and interface resistances of composites decreased significantly, indicating reduced electron–hole pair recombination. This work provides an effective way to prepare high-efficiency Bi-based photocatalysts by doping rare earth metal ions for improved photocatalytic performance.