Herein, K-OMS-2 catalysts with different levels of Ca2+ loading were synthesized to investigate the influence of Ca2+ deposition on the catalytic oxidation of CB. The micromorphology, redox ability, oxygen species, and surface acidity of the prepared catalysts were analyzed via SEM, HR-TEM, H-2-TPR, O-2-TPD, Py-IR, and GC-MS. After the Ca addition, CB conversion on the catalyst was achieved at <220 degrees C and the polychlorinated by-product yield decreased significantly. Although CaCO3 formation on the catalyst surface from Ca2+ caused a decline in number and fluidity of the surface lattice oxygen species, no significant impact on surface adsorbed oxygen species content was observed. Furthermore, CaCO3 reacted with dissociated chlorine species (HCl and polychlorinated products generated in situ), which inhibited chlorine poisoning of the active phase. (C) 2020 Elsevier Inc. All rights reserved.