Influence of Promoters (Fe, Mo, W) on the Structural and Catalytic Properties of Ni/BEA for Guaiacol Hydrodeoxygenation

Abstract

Hydrodeoxygenation (HDO) of guaiacol was investigated over BEA-supported bimetallic Ni−Fe, Ni−Mo, and Ni−W catalysts in a continuous-flow reactor. The electronic properties of Ni were significantly modified following the addition of W and Fe as analyzed by X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD), which is well in line with density functional theory (DFT) calculations, suggesting that the formation of Ni−Fe and Ni−W alloys is thermodynamically favorable while the generation of a Ni−Mo alloy is unfavored. The HDO over 9 wt % Ni/BEA catalyst was significantly improved following the incorporation of small quantities (<2.2 wt %) of Mo or Fe, while the incorporation of W decreased the HDO rate. The selectivity to hydrogenation products over the Ni−Fe/BEA catalyst was not altered compared to that of Ni/BEA during the hydrogenation of toluene, indicating that the observed increase in guaiacol conversion was engendered by the promotion of the direct hydrogenolysis of guaiacol to aromatics over Ni−Fe species. The hydrogenation and HDO rates of the Ni−Mo/BEA catalyst were both higher than those of Ni/ BEA, which was attributed to the increased Ni dispersion promoted by Mo as indicated by similar nickel turnover frequency (TOF Ni ) values observed over Ni/BEA and Ni−Mo/BEA.

Reactive Adsorption Desulfurization of Fluid Catalytic Cracking Gasoline: The Effect of Promoters (Fe, Mo, and W) on the Structural and Catalytic Properties of Ni/ZnO Adsorbents

“…The peak centered at 711.0 eV is ascribed to Fe 2p 3/2 of Fe 2 O 3 . The peak of Ni–Fe/support showed a positive shift of 0.8 eV compared to the peak of Fe/support, which indicated the electron transfer from Fe to Ni in the Ni–Fe adsorbent …”

“…34 The peak of Ni−Fe/support showed a positive shift of 0.8 eV compared to the peak of Fe/support, which indicated the electron transfer from Fe to Ni in the Ni− Fe adsorbent. 27 In the process of RADS, the adsorption of active metal Ni to olefins is mainly due to its 3d 8 4s 2 electronic configuration, and the existence of 3d vacant orbits enables it to adsorb olefin molecules by π complexation stability. 23 The migration of external electrons to Ni will increase the electron density of Ni, which will weaken the π complexation adsorption of Ni to olefin to some extent.…”

“…In fact, Fe, W, and Mo are widely used as modifiers for Ni-based catalysts because of their use in modulating the electronic structure of Ni and, thus, the catalytic activity of Ni-based catalysts, , which can be used for reference by the RADS process. These modifiers can be used to adjust the electronic structure of Ni in the adsorbent of RADS, to adjust the selectivity of the adsorbent.…”

Selective hydrogenation of vanillin over a graphene-encapsulated nitrogen-doped bimetallic magnetic Ni/Fe@NDC nano-catalyst

“…18 These catalytic systems usually require high catalyst loading, high reaction temperature, hydrogen pressure, etc., which will inevitably lead to catalyst deactivation due to aggregation and leaching of metal particles. 19 Therefore, it is very necessary to develop highly active and highly selective non-noble metal heterogeneous catalysts for the complete hydrogenation of vanillin to MMP under mild conditions.…”

The role of Ni sites located in mesopores in the selectivity of anisole hydrodeoxygenation

“…[9][10][11][12] Therefore, more attention was given to bifunctional zeolite-supported transition metal catalysts, which were endowed with particular catalytic properties. [13][14][15][16] For example, Ni-based catalysts have attracted widespread attention owing to their activity in various catalytic reactions as well as in HDO. [17][18][19][20][21] The average particle size of the active component is a crucial parameter in the reaction, and improvement of the metal dispersion not only enhances the catalytic efficiency but also provides a promising catalyst lifetime.…”