Neighboring Pd single atoms surpass isolated single atoms for selective hydrodehalogenation catalysis

Abstract

Single atom catalysts have been found to exhibit superior selectivity over nanoparticulate catalysts for catalytic reactions such as hydrogenation due to their single-site nature. However, improved selectively is often accompanied by loss of activity and slow kinetics. Here we demonstrate that neighboring Pd single atom catalysts retain the high selectivity merit of sparsely isolated single atom catalysts, while the cooperative interactions between neighboring atoms greatly enhance the activity for hydrogenation of carbon-halogen bonds. Experimental results and computational calculations suggest that neighboring Pd atoms work in synergy to lower the energy of key meta-stable reactions steps, i.e., initial water desorption and final hydrogenated product desorption. The placement of neighboring Pd atoms also contribute to nearly exclusive hydrogenation of carbon-chlorine bond without altering any other bonds in organohalogens. The promising hydrogenation performance achieved by neighboring single atoms sheds light on a new approach for manipulating the activity and selectivity of single atom catalysts that are increasingly studied in multiple applications.

A Magnetically Separable Pd Single‐Atom Catalyst for Efficient Selective Hydrogenation of Phenylacetylene

“…[ 31,32,42 ] Besides, it is often difficult to achieve high selectivity without the loss of activity as the adsorption and dissociation of H 2 were sterically hindered by the co‐adsorption of another target molecule on the isolated catalytic atoms. [ 43,44 ] As Pd 1 /Ni@G performed both high selectivity and activity, we speculated that Ni@G plays an important role in substrates adsorption. In order to verify this conjecture, we carried out DRIFTS study of phenylacetylene and styrene as adsorbates (as seen in Figure a,b).…”

Homogeneity of Supported Single‐Atom Active Sites Boosting the Selective Catalytic Transformations

“…Moreover, for the SACs with high‐density metal atoms, synergistic interactions between neighboring single metal atoms enable to efficiently promote the activation process of reactants on multiple atoms, which will be another strategy to improve the catalytic selectivity. [ 363,418 ] It has been reported that the neighboring single Pd atoms (with a single‐atom metal loading of 5.6%) display excellent activity and selectivity for carbon‐halogen bond splitting, which is superior to those of either sparsely dispersed Pd single atoms or Pd NPs. [ 418 ] Also, synergistic effects of different kinds of single metal atoms have been proposed.…”

“…[363,418] It has been reported that the neighboring single Pd atoms (with a single-atom metal loading of 5.6%) display excellent activity and selectivity for carbon-halogen bond splitting, which is superior to those of either sparsely dispersed Pd single atoms or Pd NPs. [418] Also, synergistic effects of different kinds of single metal atoms have been proposed. [199,419,420] For instance, Ir 1 Mo 1 /TiO 2 dual-SAC with two different single metal atoms exhibits much higher activity and selectivity (100% conversion with over 96% selectivity) than that of Ir 1 /TiO 2 SACs (87% conversion with 38% selectivity) and Mo 1 /TiO 2 (no activity) for the hydrogenation of 4-nitrostyrene to 4-vinylaniline.…”

Effects of Ligands on Synthesis and Surface‐Engineering of Noble Metal Nanocrystals for Electrocatalysis

“…The ensemble size of noble metal atoms on the surface of the catalyst has a great influence on the reaction path and activity in many reactions. [34][35][36][113][114][115][116][117][118][119][120][121][122] For example, the electrocatalytic MOR mainly proceeds via a CO intermediate, which requires at least three contiguous Pt atoms on the catalyst surface. [114] The ensemble size of Pt atoms also plays a decisive role in determining the reaction path of the electrocatalytic formic acid oxidation reaction (FAOR).…”