NiO-based ceramic structured catalysts for ethylene production: Substrates and active sites

P. BRUSSINO; E. D. BANÚS; M. A. ULLA; J. P. BORTOLOZZI

CATALYSIS TODAY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2022 vol. 383 p. 84 - 92

0920-5861

Structured catalysts have important advantages compared to powder formulationsand they are required for processes intensification. In this work, three different ceramicstructures: a cordierite monolith, an alumina foam and an alumina-silica paper were usedas substrates for the deposition of a NiO-Al2O3 coating and tested in the oxidativedehydrogenation of ethane to produce ethylene. For comparison, a NiO-Al2O3 powdercatalyst was also prepared. Nickel oxide species with different physicochemical featureswere obtained over each structure, evidenced by morphological (SEM-EDX) andphysicochemical characterization (XRD, LRS and XPS). The best distributions of thecatalytic coatings and NiO physicochemical properties were obtained when the monolithand the foam were used as substrates. These led to higher NiO-Al2O3 interactions and  consequently to high ethylene selectivity values, 70 - 90 %, corresponding to the former an ethane conversion of 22 % and to the latter a 5 %. The distribution of the active phaseon the ceramic paper was heterogeneous, with NiO agglomerations and poor NiO-supportinteraction thus achieving low olefin selectivity (∼30 %). The addition of a second elementsuch as cerium was also studied in those structured catalysts with high selectivity,resulting in both cases in an increment of ethane conversion but a decrease in ethyleneselectivity. This behavior was attributed to the generation of electrophilic oxygen species.