Boosting catalytic propane oxidation over PGM-free Co3O4 nanocrystal aggregates through chemical leaching: A comparative study with Pt and Pd based catalysts

Rational modification of interfacial structure and chemistry can help effectively tailor the reactivity and stability of heterogeneous catalysts regardless of their elemental or compound natures. Herein, a diluted acidic treatment was designed and utilized to modify the surface structure and chemistry of spinel Co3O4 nanoparticles. Such a chemical leaching strategy has significantly promoted the propane oxidation activity of the PGM-free Co3O4 nanocrystal aggregates. With a much higher activity than the commercial Al2O3 supported Pt and Pd catalysts, these leached nanoparticle aggregates exhibited much more abundant defects, surface Co2+ and chemisorbed oxygen species. Such surface-modified Co3O4 nanocatalysts have displayed excellent and stable propane oxidation efficiency independent of both O2 and C3H8 concentrations, where the activities of both commercial Pt (or Pd)/Al2O3 and self-made Pt (or Pd)/CeO2 catalysts were greatly affected by different O2 and C3H8 concentrations. Meanwhile, the Co3O4 nanocrystal aggregates catalyst exhibited good performance in presence of water or sulfur dioxide. This facile chemical leaching based technique provides a potential means to make highly active and stable oxide catalysts.