Enhancing Metal–Support Interactions by Molybdenum Carbide: An Efficient Strategy toward the Chemoselective Hydrogenation of α,β‐Unsaturated Aldehydes

Abstract

Metal-support interactions are desired to optimize the catalytic turnover on metals. Herein, the enhanced interactions by using a Mo2C nanowires support were utilized to modify the charge density of an Ir surface, accomplishing the selective hydrogenation of α,β-unsaturated aldehydes on negatively charged Ir(δ-) species. The combined experimental and theoretical investigations showed that the Ir(δ-) species derive from the higher work function of Ir (vs. Mo2C) and the consequently electron transfer. In crotonaldehyde hydrogenation, Ir/Mo2C delivered a crotyl alcohol selectivity as high as 80%, outperforming those of counterparts (<30%) on silica. Moreover, such electronic metal-support interactions were also confirmed for Pt and Au, as compared with which, Ir/Mo2C was highlighted by its higher selectivity as well as the better activity. Additionally, the efficacy for various substrates further verified our Ir/Mo2C system to be competitive for chemoselective hydrogenation.

Three‐Dimensionally Hierarchical Pt/C Nanocomposite with Ultra‐High Dispersion of Pt Nanoparticles as a Highly Efficient Catalyst for Chemoselective Cinnamaldehyde Hydrogenation

“…Szçllçsi et al appliedu ltrasonic irradiation to preparea series of Pt-based catalysts for the hydrogenation of CMA to CMO, and found that the selectivity towards CMO with the smaller particle size of Pt was higher than the one with the larger particle size of Pt. [62] This difference in the selectivity was explained in terms of the formation of effective metal-support active centers, which provided strong acceptors ites for C=O [63] crotonaldehyde towards crotyl alcohol, [64] and 4-nitrostyrolene towards 4-vinylaniline. [65] With similar particle size and metal loading, they attributed the pronounced enhancementso nboth hydrogenation activity and selectivity of catalysts to the strongm etal-supporti nteraction, during which the reported novel supports (H-MoO x and Mo 2 C) could donate (or gain) electrons to (or from) the active metal, thereby giving rise to superiorc atalytic performance.…”

Structural Design and Electronic Modulation of Transition‐Metal‐Carbide Electrocatalysts toward Efficient Hydrogen Evolution

“…Density functional theoretical (DFT) calculation indicated that the hybridization between d‐orbitals of M and s‐ and p‐orbitals of C obviously broadened the d‐band of M, as exemplified by Mo 2 C ( Figure ) . The resulting d‐band state similar to that of Pt contributed to noble‐metal‐like catalysis, as well as strong metal–support interactions in carbide‐supported catalysts …”

Hydrogen Doping into MoO3 Supports toward Modulated Metal–Support Interactions and Efficient Furfural Hydrogenation on Iridium Nanocatalysts

“…As shown in Figure 4c, four peaks can be deconvoluted from the Ir 4f profiles, along with one assigned to Mo 4s at 66.8 eV.T he peaks at 61.6 and 64.6 eV were ascribed to 4f 7/2 and 4f 5/2 of Ir d + , [38] respectively,a nd those at 60.8 and 63.8 eV were associated with Ir 0 . [29,39] On the sample obtained at 200 8C, dominant Ir d + and negligible Ir 0 species were observed, which is ar esult of insufficient reduction at this temperature. As the temperature was improved for reduction,t he amount Figure 4d).…”