Optimizing Both Catalyst Preparation and Catalytic Behaviour for the Oxidative Dehydrogenation of Ethane of Ni–Sn–O Catalysts

Abstract

This improved performance has been explained in terms of the decrease of the crystallite size (and the increase in the surface area of catalyst) as well as the modification of the lattice parameter of nickel oxide.

Enhanced NiO Dispersion on a High Surface Area Pillared Heterostructure Covered by Niobium Leads to Optimal Behaviour in the Oxidative Dehydrogenation of Ethane

“…For bulk NiO catalysts, NiO crystallite size has been demonstrated to play an important role in olefin formation in the ODH of ethane. [29,30] By modifying the synthesis procedure (for instance, adding organic additives, [39] or transition metal promoters [29] ), it is possible to decrease NiO average crystallite size, what generally leads to higher ethylene selectivity. In the same way, the addition of low/intermediate amounts niobium on PCH support (0-15 wt.% Nb2O5, Supports B and C) favours a lower NiO crystallite size, an improved NiO dispersion and a higher selectivity to ethylene.…”

“…related with average crystallite size of NiO, which has been reported to be one of the key factors to increase the activity and selectivity of these materials in the ODH of ethane. [29,39] For instance, increasing NiO-loading on Support C (15 wt.% Nb2O5 on PCH) decreases NiO diffraction line width, indicating an increase in NiO particle size (Figure 3a and 3), suggesting an effective interaction between the support and NiO.…”

Catalytic valorization of natural gas and biomass-derived feedstocks by metal oxides

“…Nevertheless, in some cases this is not so direct, for instance Nb-promoted catalysts show some discrepancies in this respect [160]. A similar correlation has been found with particle size of NiO catalysts, showing increasing ethylene selectivity trends when NiO particle size decreases [36,165]. This suggest that the dispersion of NiO particles (and their crystal sizes) strongly influences the catalytic behavior.…”

“…1.24). In general, an inverse correlation between the reducibility of the catalyst (measured by means of temperature-programmed reduction experiments) and the selectivity to ethylene is observed in both promoted and supported materials [165][166][167]172]. Accordingly, the lower the reducibility of Ni species in the catalysts, the higher the selectivity to ethylene achieved.…”

“…During the last decade several examples of NiO promoted by other elements have been reported. Interestingly when the metal promoter shows a high valence, like in the case of Nb 5+ , W 6+ , Ce 4+ , Sn 4+ , Al 3+ or Ta 5+ [36,37,[162][163][164][165][166][167], the selectivity to ethylene notably increases. On the other hand, when the promoter displays a low valence, like Li + or K + [36,37], the selectivity to ethylene is unaltered, or even decreases.…”