Synthesis, Characterization, and Photocatalytic Activities of (Sm/Dy/Ho)‐Doped ZnO Nanomaterials for Effective Degradation of Rhodamine B and Red CL‐5B Textile Dyes

ABSTRACT The M 0.1 Zn 0.9 O, where M 3+ = (Sm 3+ /Dy 3+ /Ho 3+ ) nanomaterials, were synthesized via the precursor method. The XRD analysis of M 0.1 Zn 0.9 O confirmed the pure hexagonal wurtzite ZnO structure. The nanomaterials were characterized by SEM/TEM, BET‐surface area, XPS, EDAX, and Raman analysis. The bandgap ( E g , eV) of materials was reduced to 3.20 eV due to the insertion of mid‐gap energy levels by M 3+ ‐dopants. The comparative photocatalytic Rhodamine B (Rh B) degradation studies performed on M 0.1 Zn 0.9 O revealed that the Ho 0.1 Zn 0.9 O exhibited the highest degradation efficiency of 98% for Rh B dye in 140 min, k = 0.9729 min −1 in UV light. The LC‐MS studied indicated complete fragmentation of the Rh B molecule by the photocatalyst. Also, Ho 0.1 Zn 0.9 O demonstrated 100% degradation of Red CL‐5B textile dye within 20 min (UV) and 80 min (sunlight). The probable reasons for improved efficiency could be attributed to the creation of efficient electron‐trap sites, enhanced charge transfer, and retardation in the (e – h + ) pair recombination rate by Ho 3+ doped in ZnO compared to Sm 3+ and Dy 3+ dopants in ZnO. The reactive species generated by the photocatalyst during the degradation process were superoxides, holes, and hydroxyl radicals. The photocatalyst displayed excellent activity and stability after three‐cycles.