Hydrodeoxygenation of m-cresol as a depolymerized lignin probe molecule: Synergistic effect of NiCo supported alloys

Abstract

Three bimetallic Ni-Co (Ni:Co ratio 1:3, 1:1 and 3:1) and two monometallic (Ni and Co) nanoparticles supported on Al2O3 were synthesized by incipient wet impregnation and characterized by various technics (N2-physisorption, XRD, H2-TPR, CO-chemisorption and elemental analysis). It was demonstrated by XRD that NiCo alloys nanoparticles were present on bimetallic solids. The catalytic properties of all catalysts were determined for the hydrodeoxygenation of m-cresol at 340 °C under 4 MPa of total pressure. It was demonstrated that NiCo alloy developed better deoxygenation catalytic properties than pure Ni metallic phase, these properties being evaluated both by the total reaction rate (kTOT) and the selectivity into deoxygenation products. Indeed, bimetallic NiCo(3:1)/Al2O3 was 1.2 times more active than Ni/Al2O3 and 8.8 times than Co/Al2O3, deoxygenated products being favored on bimetallic catalysts compared to Ni one. In addition, the kTOT values seems to be related to the amount of CO uptakes, indicating that active sites in HDO were of similar nature than those allowing the adsorption of CO, and could be oxygen vacancies which were promoted in bimetallic NiCo particles.

MOF‐derived bimetallic NiCo nanoalloys for the hydrogenation of biomass‐derived levulinic acid to γ‐valerolactone

“…The ICP‐OES analysis further confirms the presence of 21.9 wt.% and 26.1 wt.% of Ni and Co, respectively, approximate equal to a Ni/Co molar ratio of 1, again confirming the formation of bimetallic nanoalloys. Furthermore, H 2 ‐TPR results (Figure S5) show shift of reduction temperature of NiCo catalyst (496°C) compared to that of Ni/C (480°C) and Co/C (533°C), indicating the formation of NiCo nanoalloy 47 …”

Experimental and ab initio Investigation on the Effect of CO and CO2 during Hydrodeoxygenation of m‐Cresol over Co/SBA‐15

“… the direct deoxygenation (DDO route) leading to toluene, either by the direct cleavage of the C−O bond or by involving the formation of a tautomer intermediate (3‐methyl‐3,5‐cyclohexadienol) with further hydrogenation of its carbonyl group; the hydrogenation (HYD route) in which the aromatic ring is first hydrogenated yielding 3‐methylcyclohexanone and 3‐methylcyclohexanol with further dehydration to produce methylcyclohexenes and final hydrogenation to methylcyclohexane. Direct cleavage of 3‐methylcyclohexanol to methylcyclohexane can also be considered [6d,16] . The hydrogenation route also involves the passage through the tautomer intermediate (3‐methyl‐3,5‐cyclohexadienol) which can be considered as a common intermediate of both DDO and HYD routes. …”

Plasma Jet Sputtering as an Efficient Method for the Deposition of Nickel and Cobalt Mixed Oxides on Stainless-Steel Meshes: Application to VOC Oxidation

“…Numerous studies on Ni-Co mixed oxide reduction by the H2-TPR method have been reported. For example, Goncalves et al [30] The catalysts prepared at 80 Pa exhibited a very similar course of reduction as those prepared at 15 Pa, with a slight shift to higher temperatures with an increasing amount of cobalt in the catalysts. The reduction of the binary Ni-Co oxide catalysts showed an indication of peak splitting into two parts, which may involve either the reduction of several different components present in the catalysts or the reduction of particles of different sizes.…”