Determining the influence of microwave-induced thermal unevenness on vanadium oxide catalyst particles

Microwave (MW) heating accelerates various heterogeneous catalytic reactions at low temperatures, leading to energy-efficient catalytic processes. Herein we report the formation of MW–formed uneven thermal distribution at the interparticle of V₂O₅ catalyst by using microscopic thermography and electromagnetic/thermal flow simulations. The local heat generation started from the contact point of the spherical catalyst particles. The uneven thermal distribution changed as the oxidation state of the catalyst dynamically changed during the dehydration of 2-propanol. In situ Raman spectroscopy suggested that dynamic change in the thermal gradient attributes to the oxidation state of the V₂O₅ catalyst. As a result, the formation of the local hot spot at the contact point of the V₂O₅ catalyst particles, as well as the oxidation state of V₂O₅ due to MWs, synergistically affect the enhancement in the dehydration of 2-propanol. The present results provide important insights into a mechanistic understanding of the reaction enhancement of the fixed-bed flow reaction owing to the MW-induced uneven thermal distribution.