Bimetallic Nanoparticles as a Model System for an Industrial NiMo Catalyst

Abstract

An in-depth understanding of the reaction mechanism is required for the further development of Mo-based catalysts for biobased feedstocks. However, fundamental studies of industrial catalysts are challenging, and simplified systems are often used without direct comparison to their industrial counterparts. Here, we report on size-selected bimetallic NiMo nanoparticles as a candidate for a model catalyst that is directly compared to the industrial system to evaluate their industrial relevance. Both the nanoparticles and industrial supported NiMo catalysts were characterized using surface- and bulk-sensitive techniques. We found that the active Ni and Mo metals in the industrial catalyst are well dispersed and well mixed on the support, and that the interaction between Ni and Mo promotes the reduction of the Mo oxide. We successfully produced 25 nm NiMo alloyed nanoparticles with a narrow size distribution. Characterization of the nanoparticles showed that they have a metallic core with a native oxide shell with a high potential for use as a model system for fundamental studies of hydrotreating catalysts for biobased feedstocks.

Aerosol-Assisted Chemical Vapor Deposition Growth of NiMoO4 Nanoflowers on Nickel Foam as Effective Electrocatalysts toward Water Oxidation

“…The Mo 5d spectrum exhibits a doublet peak of binding energies located at 232.5 eV and 235.6 attributed with Mo3d 5/2 and Mo 3d 3/2 , respectively . The difference in binding energy (Δ E ) is ∼3.1 eV, which is typical for the Mo 6+ oxidation state in NiMoO 4 . The symmetrical O 1s spectrum shows two peaks at binding energies of 531 and 531.7 eV, characteristic of metal oxygen bonds in NiMoO 4 .…”

“…39 The difference in binding energy (ΔE) is ∼3.1 eV, which is typical for the Mo 6+ oxidation state in NiMoO 4 . 40 The symmetrical O 1s spectrum shows two peaks at binding energies of 531 and 531.7 eV, characteristic of metal oxygen bonds in NiMoO 4 . 41 The XPS observations are comparable with the previous reports on NiMoO 4 materials.…”

General Trends in Core–Shell Preferences for Bimetallic Nanoparticles

“…Some experimental reports agree with our simulations in this regard. For example, TEM analysis on Mo–Ni NPs 60 generated using spark ablation 61 indicated a mixed structure, but X-ray photoelectron spectroscopy (XPS) on the same system revealed enrichment of Ni on the surface. Tchaplyguine et al ( 62 ) investigated Cu–Ag NPs generated by magnetron sputtering, and their results agree with our results on the composition effects on the surface segregation.…”

NiMoO4@Co3O4 Core–Shell Nanorods: In Situ Catalyst Reconstruction toward High Efficiency Oxygen Evolution Reaction

“…These values are associated with the presence of Mo 6+ in NiMoO 4 . [40,41] The Mo 3d core level for NiMoO 4 @Co 3 O 4 falls at 232.28 and 235.42 eV, respectively (Figure 7a). The Ni 3p spectrum (Figure 7b 7b), both with spin-orbit splitting of 1.1 eV.…”