Tripodal Pd metallenes mediated by Nb2C MXenes for boosting alkynes semihydrogenation

Abstract

Abstract2D metallene nanomaterials have spurred considerable attention in heterogeneous catalysis by virtue of sufficient unsaturated metal atoms, high specific surface area and surface strain. Nevertheless, the strong metallic bonding in nanoparticles aggravates the difficulty in the controllable regulation of the geometry of metallenes. Here we propose an efficient galvanic replacement strategy to construct Pd metallenes loaded on Nb2C MXenes at room temperature, which is triggered by strong metal-support interaction based on MD simulations. The Pd metallenes feature a chair structure of six-membered ring with the coordination number of Pd as low as 3. Coverage-dependent kinetic analysis based on first-principles calculations reveals that the tripodal Pd metallenes promote the diffusion of alkene and inhibit its overhydrogenation. As a consequence, Pd/Nb2C delivers an outstanding turnover frequency of 10372 h−1 and a high selectivity of 96% at 25 oC in the semihydrogenation of alkynes without compromising the stability. This strategy is general and scalable considering the plentiful members of the MXene family, which can set a foundation for the design of novel supported-metallene catalysts for demanding transformations.

Functional MXenes: Progress and Perspectives on Synthetic Strategies and Structure–Property Interplay for Next‐Generation Technologies

“…The XAFS characterization of Pb/Br‐Nb 2 C is presented in Figure 7e. [ 150 ] Figure 7e(i) presents the Fourier transform extended X‐ray absorption fine structure (FT‐EXAFS) data for the Pd K ‐edge, where the Pd‐Pd bond is observed at ≈2.75 Å in R‐space allowing a scattering path. In addition to the Pd‐Pd peak, a prominent peak appears at ≈1.5 Å, which fits well the Pd‐O scattering interaction according to the PdO reference.…”

“…This method is widely used in industrialscale production and is particularly suitable for various chemical synthesis processes, including organic compound synthesis. Wei et al [150] formed a tripod 2D Pd metalloalkene structure on Nb 2 C MXene via strong metal-carrier interactions (Figure 14a). This stably structured Pd metal is capable of rapidly desorbing olefins, providing an excellent turnover frequency (TOF) of 10372 h −1 and a high selectivity of 96% at 25 °C.…”

“…Zuo et al [203] achieved in situ growth of ZnIn 2 S 4 on MXene nanosheets (Figure 14d). By preventing the stacking of ZnIn 2 S 4 [150] Copyright 2023, Nature Publishing Group. b) Circle of NOCM over Pt/Mo 2 TiC 2 T x thermocatalysts (TS, transition state).…”

“…a) Interaction energy between Pd and support as a function of the number of Pd layers in MD simulations of Pd/ Nb 2 C MXene catalysts. Reproduced with permission [150]. Copyright 2023, Nature Publishing Group.…”

Pd–Mn/NC Dual Single-Atomic Sites with Hollow Mesopores for the Highly Efficient Semihydrogenation of Phenylacetylene

“…However, the presence of enriched phenylacetylene during the extraction process will severely poison the catalyst used in styrene polymerization. , To address this issue, the highly selective semihydrogenation of alkynes has been explored as an effective method to convert phenylacetylene into styrene before polymerization. − In previous studies, nano-Pd catalysts have been considered highly efficient catalysts for this reaction due to their exceptional ability to activate H 2 and unsaturated hydrocarbons. However, their undesired activity toward overhydrogenation leads to the formation of ethylbenzene. − Strategies such as poisoning or covering part of metal sites have been employed to suppress these side reactions, which inevitably resulted in the decrease in catalyst activity and metal utilization. − Therefore, the development of novel catalysts with both high selectivity and efficient utilization of the metal atom for the semihydrogenation of phenylacetylene still holds immense significance.…”