Microporous exposure on catalytic performance of MoVNbTeOx mixed metal oxides in the oxidative dehydrogenation of ethane

The catalytic performance of the non-purified MoVNbTeO x catalyst was optimized by changing the composition of the synthesis gel method in the hydrothermal synthesis process. However, the enhancement in activity was more pronounced for the post-treatment process of the non-purified catalyst. The catalytic performance of non-purified MoVNbTeO x catalysts and phase-pure M1 catalysts in the oxidative dehydrogenation of ethane (ODHE) were enhanced by water agitation post-treatment. The results showed that the phase-pure M1 catalyst obtained by treating the MoVNbTeO x catalyst with nitric acid had an increased activity per unit mass, but with a mass loss of catalyst materials during the purification process. After several days of post-treatment with water agitation, the catalytic activity of the non-purified MoVNbTeO x and the M1 samples gradually increased and stabilized, where both catalysts had a comparable catalytic performance. All the samples were systematically characterized, showing that the catalytic performance of the samples was mainly correlated with the enhanced specific surface area/pore volume. The results show that for the hydrothermally synthesized MoVNbTeO x catalysts, the reaction takes place in the micropores and the key to improve the performance of MoVNbTeO x catalysts is to effectively expose the active sites. Physical post-treatment process that does not require nitric acid or hydrogen peroxide for purification is also effective in enhancing catalyst activity by boosting the active site.