Pocketlike Active Site of Rh₁/MoS₂ Single-Atom Catalyst for Selective Crotonaldehyde Hydrogenation

Abstract

Selective hydrogenation of unsaturated aldehydes to unsaturated alcohols is a valuable but challenging task for synthesizing fine chemicals. We report that single Rh atoms anchored to the edges of 2D MoS2 sheets can efficiently convert crotonaldehyde to crotyl alcohol with 100% selectivity via a steric confinement effect of pocketlike active sites. Characterization results suggest that the synthesized Rh1/MoS2 single-atom catalysts (SACs) possess a unique geometric and electronic configuration, which confines the adsorption mode of the reactant molecule by a steric effect. The DFT calculations suggest that the MoS2 sheets terminate with oxidized Mo edges and the Rh1 stably anchors at the Mo cation vacancy site, which can facilely dissociate H2 to H atoms. The dissociated H atoms spill over to react with the edge O atoms to form OH species and create an HO–Mo–Rh1–Mo–OH configuration, resembling a pocketlike active site, which confines the adsorption mode of the crotonaldehyde due to steric effects. Such specific adsorption configuration yields 100% selectivity. The strategy of constructing pocketlike active centers with single metal atoms and 2D nanosheets opens new approaches to designing highly selective SACs for specific classes of catalytic transformations.

Recent advances in single metal atom-doped MoS2 as catalysts for hydrogen evolution reaction

“…What is more, the good CO tolerance of Pt doped MoS 2 further demonstrated that Pt substituted Mo rather than S. According to the DFT study, the Pt will be poisoned by CO if Pt substituted the S site due to the strong binding between CO and Pt (1.50 eV), while Pt will be "buried" under the S layer if substituting Mo and HER performance will not be influenced by the CO tolerance measurement, which matched well with the experimental measurement. SA-Au and SA-Pd doped MoS 2 as HER catalysts have also been explored by the authors and enhanced HER activity was observed, consistent with other reports [58,59]. Furthermore, other precious metal atoms were doped into Reproduced with permission from Ref.…”

“…[41]. Copyright 2019 ACS the lattices of MoS 2 for HER application and showed an enhanced performance, including Pd [57], Rh [59] and Ru [36].…”

In Situ Dispersion of Palladium on TiO2 During Reverse Water–Gas Shift Reaction: Formation of Atomically Dispersed Palladium

“…In the past decade the catalysis community has observed an explosive growth in interest on catalysis by atomically dispersed supported (noble) metals. [1][2][3] These so-called singleatom catalysts (SACs) or site-isolated catalysts are intriguing candidates to maximize metal utilization efficiency, [4] enhance selectivity, [5][6][7][8][9][10] and investigate structure-activity relationships due to site homogeneity. [11][12][13][14][15][16] Theaforementioned characteristics endow this catalyst class with the promise of unifying the industrial advantages of homo-and heterogeneous catalysis, while mitigating their disadvantages.…”

Surface Molecule Manipulated Pt/TiO2 Catalysts for Selective Hydrogenation of Cinnamaldehyde

“…Previous attempts to improve the chemoselectivity of metal nanocatalysts mainly focused on controlling the size, shape and composition of metal NPs, and, the interactions between metal and supports (1-6). More recent researches have seen an increased focus on understanding the interactions between adsorbates at nanoscale interfaces of heterogeneous catalysts (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). But, how these interactions can be precisely regulated to tune the chemical reactivity remains elusive.…”