New Formulations of Ni-Containing Ceramic Papers to Enhance the Catalytic Performance for the Oxidative Dehydrogenation of Ethane

Abstract

Ceramic papers composed of silica−alumina fibers structured using colloidal suspensions as binders constitute interesting materials to be used as flexible supports of catalytic materials. The deposition of Ni as the active ingredient together with Zr or Ce promoters resulted in active and selective structured catalysts for the oxidative dehydrogenation of ethane; these structured catalysts also exhibited acceptable mechanical properties. The employed binder agents (nanoparticles of ceria, zirconia, or yttria-stabilized zirconia) homogeneously covered the fiber surface, contributing to the dual function of building a threedimensional arrangement and favoring the anchoring of the catalytic formulations. The prepared papers showed nickel oxide as the active phase. The incorporation of cerium or zirconium as promoters enhanced the catalytic properties. The former element mainly produced an increase in ethane conversion, whereas the latter markedly improved ethylene selectivity. In both cases, an ethylene productivity was obtained in the promoted systems which was higher than that in the unpromoted samples. It is likely that the formation of the solid solutions Ni−Ce−O and Ni−Zr−O, as suggested by X-ray diffraction and laser Raman spectroscopy analyses, plays an important role in these effects. The best catalyst was the one containing nickel as the active phase, Ce as the promoter, and ZrY as the binder agent, for which ethylene productivity at 400 °C was ca. 513 g ethylene/(kg cat h). The binder agent addition was necessary to join the fibers, thus improving the mechanical properties of the papers, but they also affected the catalytic performance through the coverage of ceramic fibers and the resulting interaction with the catalytic compounds. The performed tensile index tests showed that the colloidal suspension of ceria produced papers with mechanical properties better than those of zirconia or zirconia−yttria because they exhibited greater resistance and flexibility.

Novel Ni-Ce-Zr/Al2O3 Cellular Structure for the Oxidative Dehydrogenation of Ethane

“…This point confirms that crystalline zirconium oxide is not present, not even in the sample with a higher amount of Zr, in agreement with XRD results. Differently, at increasing Ce content in the samples, the characteristic band at 462 cm −1 of cerium oxide with fluorite-type structure appears with higher intensity in the spectra, along with two additional bands at 225 and 635 cm −1 , directly related to the CeO2 lattice defects caused by oxygen vacancies and the modification of the oxygen sub-lattice [13,25,[26][27][28][29][30][31].…”

“…It has been reported that the bands at 225 and 635 cm −1 point out the formation of a Ni-Ce-O solid solution [13], but in these samples they could also indicate that part of the zirconium is present as a Ce-Zr-O solid solution.…”

FeCrAlloy Monoliths Coated with Ni/Al2O3 Applied to the Low-Temperature Production of Ethylene

“…The structured catalysts located in a quartz reactor (Ø = 16.3 mm). The thermocouple was placed as illustrated in [28]. Particularly, the Ni-Al-M3C structured catalyst was previously wrapped with quartz wool to force the feed flow through the channels, taking into account that the outer face of the housing was not coated with catalyst.…”

“…Some of them offer lower pressure drop, higher energy efficiency, allow detailed designs, and ease scaling-up, among others [20,21]. The substrates that have been studied for the preparation of structured catalysts are ceramic foams [22], ceramic monoliths [23][24][25], ceramic papers [26][27][28], metallic foams [22,29], and metallic monoliths [5,30].…”

Ultrasound-Assisted Deposition of Co–CeO2 onto Ceramic Microfibers to Conform Catalytic Papers: Their Application in Engine Exhaust Treatment

“…Catalytic ceramic papers have been reported to be efficient for a variety of gas-phase reactions with industrial and environmental concern. Among them, reforming reactions, − hydrocarbon dehydrogenation, , nitric oxide reduction, , and CO oxidation have been studied.…”