Chemoselective hydrogenation of α,β-unsaturated aldehydes on hydrogenated MoOx nanorods supported iridium nanoparticles

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.…”

Porous, Naturally Derived Hafnium Phytate for the Highly Chemoselective Transfer Hydrogenation of Aldehydes with Other Reducible Moieties

“…To date, direct hydrogenation with the use of H 2 as the reductant and catalytic transfer hydrogenation (CTH) with secondary alcohols are two routes that are commonly used for the reduction of aldehydes with ORMs, and great efforts have been devoted to exploring efficient and selective catalytic systems. In general, supported transition metals (e.g., Ru, Pd, Au, Pt, Cu, Co, Ir, and Ni) and metal complexes have been the most studied catalysts for this important transformation, but the selectivities for alcohols with unreduced ORMs are often poor or difficult to control owing to competitive adsorption and reduction between the aldehyde group and the ORMs on the catalytic active centers. Although the selectivity towards alcohols with unreduced ORMs can be enhanced by designing novel ligands for metal complexes; by introducing additives, other metal components, and functional supports; and by designing special structures for supported catalysts, the complex preparation routes, the high cost, and the stability and recyclability of these catalytic systems still limit their large‐scale application.…”

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

“…Hydrogen temperature-programmed reduction (H 2 -TPR) analysisc learly identifiedt he reduction of Ir 4 + speciest om etallic Ir on the MoO 3 surface at around 192 8C, [29] and the following hydrogen consumption at 218 8Cc ould be ascribed to the Hd oping into MoO 3 supports ( Figure 1a). [19] The easier reduc-tion of MoO 3 at such low temperature, in comparison with that for bare MoO 3 at around4 96 8C, can be ascribed to theH 2 spillover from Ir NPso nto the MoO 3 surface. Typically,t he in situ formed Ir sites can dissociate chemisorbed hydrogen molecules to highly active hydrogen atoms, which migrate and furtherd iffuse into MoO 3 ,s imultaneously generating H-doped MoO x .…”

“…[15][16][17] Our recent work also discovered that the strong electronic metal-support interactions that arise from HÀMoO x can alter the surfacec harge state of metals( e.g.,P t, PtÀSn, Ir)a nd contributet ot he selectiveh ydrogenation of functionalized nitroarenes and a,b-unsaturated aldehydes. [18,19] To achieve efficient catalysis on defined surface/interfaces, controlled Hd oping into metal oxide supports is highly desirable, although it is difficult by means of direct H 2 treatment. Very recently,h ydrogen spillover on metalsh as been demonstrated to be feasible in hydrogenating metal oxide supports in situ, whereby the Hd oping can be easily controlled by simply varying the temperature during reduction.…”