Anchoring Positively Charged Pd Single Atoms in Ordered Porous Ceria to Boost Catalytic Activity and Stability in Suzuki Coupling Reactions

Abstract

Single‐atom (SA) catalysis bridging homogeneous and heterogeneous catalysis offers new opportunities for organic synthesis, but developing SA catalysts with high activity and stability is still a great challenge. Herein, a heterogeneous catalyst of Pd SAs anchored in 3D ordered macroporous ceria (Pd‐SAs/3DOM‐CeO2) is developed through a facile template‐assisted pyrolysis method. The high specific surface area of 3DOM CeO2 facilitates the heavily anchoring of Pd SAs, while the introduction of Pd atoms induces the generation of surface oxygen vacancies and prevents the grain growth of CeO2 support. The Pd‐SAs/3DOM‐CeO2 catalyst exhibits excellent activity toward Suzuki coupling reactions for a broad scope of substrates under ambient conditions, and the Pd SAs can be stabilized in CeO2 in long‐term catalytic cycles without leaching or aggregating. Theoretical calculations indicate that the CeO2 supported Pd SAs can remarkably reduce the energy barriers of both transmetalation and reductive elimination steps for Suzuki coupling reactions. The strong metal‐support interaction contributes to modulating the electronic state and maintaining the stability of Pd SA sites. This work demonstrates an effective strategy to design and synthesize stable single‐atom catalysts as well as sheds new light on the origin for enhanced catalysis based on the strong metal‐support interactions.

Pd‐Single‐Atom Coordinated Biocatalysts for Chem‐/Sono‐/Photo‐Trimodal Tumor Therapies

“…The depicted contour plot of Pd foil ( R = 2.3 Å, k = 8.9 Å −1 ) (Figure 2g) is used as the control; the Pd‐Pta/Por clearly shows the resolved spectra in both R‐space ( R = 1.5 Å) and k‐space ( k = 4.8 Å −1 ) (Figure 2h), aligning well with the lower contour of PdO ( R = 1.2 Å, k = 4.2 Å −1 ) (Figure 2i). [ 50 ] Thus, the XAS and XPS data confirm the detailed Pd coordination sites in Pd‐Pta/Por that involves Pd coordination by N and Cl.…”

Two-dimensional heterostructures built from ultrathin CeO2 nanosheet surface-coordinated and confined metal–organic frameworks with enhanced stability and catalytic performance

“…3h) and the CeO 2 uorite crystal (460 cm À1 ). 49 The Raman signals of CeO 2 -BDC emerge at approximately 217, 350, 440 and 462 cm À1 (Fig. S27c †), and the Raman signal at 217 cm À1 was previously ascribed to a functionalization related to phonon mode.…”

Synchrotron-radiation spectroscopic identification towards diverse local environments of single-atom catalysts

“…For instance, synchrotron-radiation COprobing DRIFTS results of Pd SAs, H 2 -treated Pd SAs and Pd NPs denoted as Pd-SAs/3DOM-CeO 2 , Pd-SAs/3DOM-CeO 2 -H 2 and Pd-NPs/3DOM-CeO 2 respectively, were contrasted by Tao and coworkers. 154 The sharp peak at 2153 cm À1 belongs to strhing variation of linear-adsorbed CO on Pd SAs, indicating atomic dispersion in Pd-SAs/3DOMCeO 2 (Fig. 13b).…”