The effect of V in La2Ni1-xVxO4+1.5x+delta on selective oxidative dehydrogenation of propane: Stabilization of lattice oxygen

In this study, the non-stoichiometric redox compounds La2NiO4+δ and La2Ni0.9V0.1O4.15+δ have been tested as an oxidant in selective oxidation of propane in pulse experiments at temperatures between 450 and 650 °C. The oxygen contents in the samples at different temperatures were calculated based on back-titration with O2 pulses as well as on TGA. In the case of La2Ni0.9V0.1O4.15+δ over-stoichiometric oxygen was the only active species, responsible for the formation of CO2, C3H6, C2H4 and CH4 while pulsing propane at all investigated temperatures. Contrary, the reactive species in La2NiO4+δ changed from over-stoichiometric oxygen only at 450 °C, to both over-stoichiometric and lattice oxygen at 550 °C, to lattice oxygen only at 650 °C. The activation of lattice oxygen and the consequent formation of Ni metal were detrimental for selectivity to propylene as formation of COx, CH4 and coke mainly occurred and no olefins were formed.