Ni–Co–O solid solution dispersed nanocrystalline Co3O4 as a highly active catalyst for low-temperature propane combustion

Abstract

Co₃O₄ and NiO have been widely studied as catalysts for catalytic combustion because of their high oxygen mobility, both theoretically and experimentally. Research into their combination to make highly dispersed nanocrystalline Co₃O₄ is rare. Here we prepared a Ni–Co–O solid solution dispersed nanocrystalline Co₃O₄ of NiO–Co(0.3) as a highly active and stable catalyst for propane combustion by a simple co-precipitation method. Superior to pure oxides, the specific rate (μmol_C3 g_cat⁻¹ h⁻¹) of NiO–Co(0.3) at 170 °C is 2.5 times as high as pure Co₃O₄, whereas the pure NiO is inert at this temperature. The nanocrystalline Co₃O₄ particles surrounded by active O species are the main active sites for NiO–Co(0.3) catalyst. The synergistic effects between the nanocrystalline Co₃O₄ particles and Ni–Co–O solid solution with high oxygen mobility give the high propane combustion activity. Further research shows that the highly active performance relates directly to the surface Co content, Co²⁺ species and active O species. Our findings offer insight into the preparation of highly active nanocrystalline Co₃O₄ dispersed on transition oxides, which is different to that previously reported.