Precise design and synthesis of Pd/InOx@CoOx core-shell nanofibers for the highly efficient catalytic combustion of toluene
Pd/InOx@CoOx core-shell nanofibers, CoOx@Pd/InOx core-shell nanofibers and Pd/InOx/CoOx nanofibers with different morphologies have been successfully synthesized for the catalytic combustion of toluene. Among them, the Pd/InOx@CoOx core-shell sample is novelly composed of Pd/InOx nanotubes core, CoOx nanocubes and CoOx nanoparticles shell derived from ZIF-67. On the contrary, the CoOx@Pd/InOx core-shell catalyst is assembled by CoOx nanocubes core and Pd/InOx nanotubes shell. Finally, the Pd/InOx/CoOx nanofibers as reference are synthesized with the similar method of CoOx@Pd/InOx core-shell sample. Interestingly, the Pd/InOx@CoOx core-shell sample displayed the best activity for toluene oxidation with T90 = 253 °C, good thermal stability and good cyclic stability during the three runs. Through some characterizations, it is verified that the Pd/InOx@CoOx core-shell sample exhibited best performance for toluene oxidation reaction due to the larger specific surface area, higher reducibility, richer defective structure and oxygen vacancy, higher proportion of Pd0, Co3+ species and higher lattice oxygen species than others. Simultaneously, Pd/InOx@CoOx core-shell sample exhibited good thermal stability and cyclic stability, which might due to the protective layer of CoOx shell to protect the stability of Pd nanoparticles core.