Promoting the catalytic activity of SmyCoOx on oxidation of toluene and o-xylene by Sm doped Co3O4 to weaken the Co–O bonds

Abstract

Cobalt-based catalysts are the most promising catalysts for the catalytic oxidation of volatile organic compounds (VOCs). Metal doping is considered to be a valuable strategy to improve the catalytic activity of metal oxide catalysts. Here, a small amount of Sm doped Sm_yCoO_x spinel oxides with walnut-like shape were successfully prepared by solvothermal method and applied for oxidation of toluene and o-xylene. Their physiochemical properties were studied by various characterization, DFT calculation and in situ DRIFIS tests. Sm_0.09CoO_x substituted by Sm at six-coordination cobalt shows the best oxidation ability on toluene (T₉₀ = 228 °C) and o-xylene (T₉₀ = 268 °C). This is because doping Sm in Co₃O₄ causes the lattice distortion, and generates Sm-O-Co bonds to weaken the bond energy of Co-O bonds, thus inducing the generation of active oxygen by improving the mobility of lattice oxygen. These results are of great significance for constructing metal–oxygen bonds through metal-doped cobalt oxide catalysts to improve catalytic performance.