Isobutanol dehydrogenation on copper-containing bismuth vanadates

It is found that α, β, and γ modifications of perovskites Bi4V2 - 2xCu2xO11 - δ (BICUVOX) exhibit different activities during catalytic transformations of isobutanol with a selectivity of isobutanal formation 85-100%. Data analysis shows that the site for the alcohol dehydrogenation reaction is the ion pair Cu2+- O2- with the highest activity for a highly conductive γ-phase. It is shown that the activation energy for aldehyde formation is lower for γ-phase of the catalyst by a factor of ten than that for its α-phase. It is concluded that step-wise Arrhenius dependences without changes in the activation energy for parallel alcohol dehydrogenation and dehydration reactions are related to changes in the conducting properties of the catalyst. Step change in activity was found at temperatures of 310 and 370° and corresponds to an increase of the solid solution electric conductivity. © Pleiades Publishing, Ltd., 2013.