Pd Nanoparticles Decorated on ZnO/Fe₃O₄ Cores and Doped with Mn²⁺ and Mn³⁺ for Catalytic C–C Coupling, Nitroaromatics Reduction, and the Oxidation of Alcohols and Hydrocarbons

Abstract

In spite of the enhanced catalytic performances exhibited by the doped transition nano-metal catalysts, understanding and unraveling the mechanistic part behind the promotional nature of dopants remains a challenge. The present work involves a comparative analysis of Mn3+- and Mn2+-doped supported Pd nano-catalysts with undoped counterparts for C–C coupling, reduction, and oxidation. Efforts were made to gain deep insights into the promotional role of dopant ions. X-ray photoelectron spectroscopy spectra of fresh and reused catalysts in case of each organic transformation provided mechanistic insights into the role of dopant ions which has proved helpful in formulating mechanisms where the electronic synergism between dopants and reactant/metal nanoparticles has been depicted. The effect of Mn3+ ions on the electronic environment of aryl halide in case of C–C coupling makes the Mn3+-doped nano-catalyst more efficient, as compared to Mn2+-doped and undoped nano-catalysts. The strong electronic interactions between Mn2+ and Pd make the Mn2+-doped nano-catalyst efficiently active and selective for reduction and oxidation. The present approach provides proper evidence for the changes/interactions that are induced by the introduction of dopants in heterogeneous nano-metal catalysts. Consequently, the underlying synthetic route to design efficient doped heterogeneous transition nano-metal catalysts and a deeper mechanistic view of the promotional role of dopant will prove to be a promising approach in the field of heterogeneous nano-metal catalysis.

Pd nanoparticles supported on magnetic CoTiMgLDH with enhanced catalytic activity in Suzuki cross‐coupling and reductive degradation of dyes

“…The orbital scan of Pd (3d) showed two peaks at binding energies (BE) of 335 and 340.2 eV, which were assigned to the 3d 5/2 and 3d 3/2 state of metallic palladium (Pd 0 ) [Figure 2a (a) ]. These binding energy values showed a negative shift of ~0.5 eV in comparison to the reported values of Pd 0 27,28 . This result indicated an increased electron density on Pd 0 NPs in Pd/Fe 3 O 4 ‐CoTiMgLDH.…”

Fast one-pot synthesis of a Se-rich MnCdSe solid solution for highly efficient cocatalyst-free photocatalytic H2 evolution

“…23 Meanwhile, the peak at around 640.66 eV corresponds to the Mn 2p 3/2 of Mn 3+ . 24 As displayed in the Cd 3d spectrum of CdSe (Fig. 3b), the two characteristic peaks at 405.08 and 411.82 eV are associated with Cd 3d 5/2 and Cd 3d 3/2 of Cd 2+ .…”

Adsorption of Cu Nanoparticles on Polystyrene-Based Microspheres

“…Based on the nanoparticles’ preparation process, the fabrication of such composite microspheres can be categorized into in situ reaction and adsorption. The metal salts are adsorbed on the microspheres, followed by reduction to generate metal nanoparticles in the in situ reaction method. − This method is commonly employed, for instance, SiO 2 was synthesized through a sol–gel process on the surface of polymer microspheres, and Ag NPs coated polystyrene (PS) microspheres were obtained by adsorption of Ag + ions succeeded by reduction on sulfonated PS microspheres . However, the method exhibits limitations in effectively regulating the diameter, size distribution, and morphology of the nanoparticles.…”