Oxygen carrier prepared by solvent-free grinding and biomass based oxygenates for chemical looping oxidative dehydrogenation of isobutane

Abstract

The chemical looping oxidative dehydrogenation of isobutane is an effective and novel strategy for producing isobutene. It is extremely necessary but challenging to design excellent oxygen carriers for this strategy. Here, a solvent-free grinding approach is presented to prepare ZnMo0.45V0.55Ox oxygen carrier with tailorable oxygen vacancy content via biomass based oxygenate as carbothermal reductive agent. As a result, ZnMo0.45V0.55Ox-0.3 vitamin C oxygen carrier demonstrates a much higher isobutane conversion of 17.61 % and isobutene selectivity of 82.55 %, whereas it is 7.99 % of isobutane conversion and 22.66 % of isobutene selectivity for ZnMo0.45V0.55Ox without vitamin C addition. The performance for the ZnMo0.45V0.55Ox-0.3 vitamin C is closely related to the surface area and the metal-oxygen bond strength. Large surface area can provide more accessible active sites, which can facilitate the isobutane's diffusion, adsorption and activation. High oxygen vacancy content results in weak metal-oxygen bond strength, which leads to high mobility of lattice oxygen.