La and F co-doped Bi2MoO6 architectures with enhanced photocatalytic performance via synergistic effect
Abstract
Novel La and F co-doped Bi2MoO6 architectures were first successfully synthesized via a facile solvothermal process, and characterized using XRD, SEM, TEM/HR-TEM, XPS, EDS, UV-Vis DRS and PL spectra. The enhanced photocatalytic activities of La and F co-doped Bi2MoO6 architectures were evaluated by the photodegradation of rhodamine B (RhB) under visible-light irradiation. The results demonstrated that the F-1.0 at% La–Bi2MoO6 photocatalyst exhibits significantly enhanced photocatalytic activity, which is 6.54 times higher than that of pure Bi2MoO6. The cause can be attributed to the co-incorporation of La and F into Bi2MoO6 broadening the absorption in the visible-light region and thereby leading to the formation of new energy levels on top of the valence band of F–La–Bi2MoO6, and on the other hand, the synergistic effect of F and La, in which F doping led to the increase of absorptivity of F–Bi2MoO6 and acted as an n-type impurity to supply a hole carrier. The doped La3+ ions act in a key role to capture and transfer/release the photogenerated electrons for conversion from O2 to ·O2− to delay the recombination of the photogenerated electrons and holes, greatly suppressing the recombination of photogenerated electron–hole pairs and thus significantly improving photocatalytic activity in RhB photodegradation. The radical capture experiment confirmed that h+ and ·O2− were the main active species and were responsible for RhB photodegradation. Moreover, on the basis of the PL spectra, active species trapping detection and photocurrent response experiments, the mechanism of the enhanced photocatalytic activity for F–La–Bi2MoO6 was proposed.