A series of CuxCo3−xO4 catalysts were prepared and presented as active and stable catalysts in the oxidation of
CO into CO2 at relatively low temperatures. These nanoparticles were synthesized by co-precipitation assisted
ultrasonic radiation method. The thermal behavior, structural, spectroscopic, texture, and morphological
characterizations were carried out adopting TG-DTA, XRD, XPS, FTIR, N2-sorption, and TEM techniques. In
addition, electrical conductivity and surface chemisorbed oxygen measurements were also studied. The quantity
and strength of basic sites were estimated using CO2-TPD. The results revealed that the insertion of Cu2+ with
values of x from 0.25 to 0.75, into Co3O4 catalysts calcined at 400 °C monotonically increases the SBET, the
amount of surface chemisorbed oxygen, catalyst basicity, electrical conductivity and catalytic activity. In addition,
the activity increases to an optimal amount of Cu2+ substitution for Co2+ with x=0.75 which exhibited
the most active catalyst with a value of T100 of 125 °C. Results of CO2-TPD demonstrated that, incorporation of
Cu2+ with a value of x of 0.75 not only increases the total basicity, but also altered strength and distribution of
basic sites over the surface of the catalyst. The role of the active redox sites existed on the surface of these
catalysts such as, Co3+/Co2+, Cu2+/Cu+ and Co3+/Cu+, which are accountable for such alteration, was also
debated. The most active catalyst Cu0.75Co2.25O4 displayed a long-term stability up to 100 h.