^aDivision of Physical Science, Faculty of Science, Prince of Songkla University,

Hat Yai, Songkhla 90112, Thailand

^bMaterials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand

^cDepartment of Chemistry, Faculty of Science, Chiang Mai University,

Chiang Mai 50200, Thailand

^dDepartment of Physics and Materials Science, Faculty of Science,

Chiang Mai University, Chiang Mai 50200, Thailand

ZnO and Ce/Mg co-doped ZnO nanoparticles as a visible-light-driven photocatalyst were synthesized by combustion method. X-ray diffraction (XRD) patterns of ZnO and Ce/Mg co-doped ZnO samples were indexed to the pure phase of hexagonal wurtzite ZnO structure without impurity detection. The Raman analysis of ZnO and Ce/Mg co-doped ZnO samples showed optical phonon E2H, A1(TO), E2L, E2H–E2L, A1(LO) and E1(LO) modes of wurtzite ZnO structure, including the detection of Zn−O stretching mode containing in FTIR spectra of hexagonal wurtzite ZnO. Transmission electron microscopic (TEM) images of ZnO and Ce/Mg co-doped ZnO samples showed uniform and good distribution of nanoparticles with different orientations. The photocatalysis of ZnO and Ce/Mg co-doped ZnO nanoparticles was studied through the degradation of methylene blue (MB) illuminated by visible radiation. In this research, the Zn0.97Ce0.015Mg0.015O nanoparticles have the highest efficiency of 95.16% within 150 min because of the largest specific surface area, smallest crystallite size and highest absorption capacity of visible light for active species production in degrading of MB under visible light. Photocatalytic mechanism ofCe/Mg co-doped ZnO nanoparticles in degrading MB was also proposed.