Fundamental understanding of the Di-Air system (an alternative NO x abatement technology). I: The difference in reductant pre-treatment of ceria

•The reactivity of H2, CO, C3H6, and C3H8 as a function of the reduction degree and rate of Zr–La doped ceria by using Temporal Analysis of Product was investigated.•As compared to H2, CO yielded a faster catalyst reduction rate and higher final degree of reduction.•CO cannot rival the hydrocarbons at a temperature of at least 500°C for C3H6 and 540°C for C3H8. The use of hydrocarbons yielded an almost three times deeper degree of catalyst reduction.•The high conversion rate of hydrocarbon(s) is observed both over the oxidised and reduced ceria surface.•The use of hydrocarbons yielded an almost three times deeper degree of catalyst reduction and with large amounts of carbonaceous deposits left.