Hydrodeoxygenation of Guaiacol as a Bio-Oil Model Compound over Pillared Clay-Supported Nickel–Molybdenum Catalysts

Abstract

Pillared clay-supported NiMo catalysts were synthesized in their reduced and sulfided forms and applied to the hydrodeoxygenation of guaiacol (2-methoxyphenol) as a bio-oil model compound. The sulfided catalyst displayed better activity and selectivity as compared to the reduced catalyst, yielding phenol as the major product. Quasielastic neutron scattering demonstrated that jump diffusion of guaiacol was seen after adsorption on both the sulfide catalyst and pillared clay. Inelastic neutron scattering was carried out in conjunction with an infrared study and reveal that there were two types of interaction of guaiacol with the catalyst. The first is guaiacol adsorbed via various types of H-bonding interaction, as observed in the sulfided catalyst. The second type of interaction is guaiacol adsorbed on the surface, presumably at a Mo vacant site, by chemisorption through formation of a methoxyphenate species as seen in the reduced catalyst. The interactions were greater in the sulfided catalyst by which guaiacol was selectively adsorbed in coordination with the Ni–Mo–S site.

A Sustainable Palladium‐Intercalated Montmorillonite Clay Catalytic System for Imine Hydrogenation under Mild Conditions

“…This indicates the preferential growth of (111) plane. [33] XRD pattern in Figure 1 shows neither peak shifting of d(001) plane of clay nor its disappearance as observed in earlier literature reports. [33][34] This may be due to spacing irregularity of clay layers upon intercalation resulting in presence of Pd particles on the clay layers.…”

“…[33] XRD pattern in Figure 1 shows neither peak shifting of d(001) plane of clay nor its disappearance as observed in earlier literature reports. [33][34] This may be due to spacing irregularity of clay layers upon intercalation resulting in presence of Pd particles on the clay layers. However, a significant decrease in the intensity of (001), (002) and (003) planes of the montmorillonite clay is observed upon metal loading (see Figure S1b, c and d), which indicates the effective The interplanar d-spacing of 2.6 Å and 2.3 Å corresponds to the Pd(111) plane for 2 % Pd/Clay and 10 % Pd/Clay respectively.…”

“…It is observed that as the Pd loading in clay increases, the intensity of (111) plane increase gradually ( Figure 1 b, c, d and e ). This indicates the preferential growth of (111) plane [33] . XRD pattern in Figure 1 shows neither peak shifting of d(001) plane of clay nor its disappearance as observed in earlier literature reports [33–34] .…”

Net Zero and Catalysis: How Neutrons Can Help

“…The β-O-4 linkage (red rectangle in Figure 6) constitutes 48−60% of the total interunit linkages in lignin, as such, it is a key target for depolymerisation of lignin. Guaiacol (2-methoxyphenol) is a commonly used model compound for this link and its hydrodeoxygenation has been investigated by INS and QENS spectroscopies [79]. Pillared clay-supported NiMo catalysts were used, Cellulose and hemicellulose are relatively easy to process, but one of the most abundant, but most recalcitrant, forms of biomass is lignin.…”

Understanding the Surface Characteristics of Biochar and Its Catalytic Activity for the Hydrodeoxygenation of Guaiacol

“…The production of second-generation biofuels involves the pyrolysis of lignocellulose into bio-oil followed by upgrading via a hydrodeoxygenation (HDO) process to remove oxygen [3,6]. Bimetallic metal sulfides (e.g., NiMoS, CoMoS) have been one of the most widely studied catalysts for HDO [7][8][9], but the search for a suitable support material to increase the stability of the active metal centers, or act as the catalyst itself, remains a challenge. Activated carbons have been reported to offer higher stability in HDO systems compared to alumina and silica due to the weak acidity [10,11], but the extensive microporosity is a drawback which inhibits reactions involving large molecules [12].…”