A minireview on the synthesis of single atom catalysts

Abstract

The two routes for the synthesis of SACs are reviewed and the advantages and disadvantages of each method are compared.

Mechanism insights on single-atom catalysts for CO2conversion

“…59 Although it is easy to synthesize SACs using the photochemical reduction method, it is difficult to uniformly distribute the active sites owing to the co-existence of single sites and continuously packed sites. 60…”

Elucidation of single atom catalysts for energy and sustainable chemical production: Synthesis, characterization and frontier science

“…Nevertheless, the metal loadings of the SAC synthesized from SEA method are usually kept low (<5wt%) [125]. Besides, the adsorption behavior is highly sensitive to the types of functional groups and the presence of defects on the support surface [124]. This is problematic since this method is heavily dependent on the electrostatic interaction to achieve atomic dispersion on the support surface.…”

“…• The pH of the solution is tuned to maximize the electrostatic interaction between metal precursors and the oxide surface [123] • The metal precursor will be adsorbed onto the surface under the desired pH environment [124] • Best suited for low metal loadings [125] • Adsorption behavior is heavily dependent on the unique topology of the support (defects, functional groups, etc.) [124] Ball-milling • Initiate physical and chemical transformation between catalysts precursors via mechanical energy (known as "mechanochemistry"…”

Recent Advances in Anode Electrocatalysts for Direct Formic Acid Fuel Cells – Part I – Fundamentals and Pd Based Catalysts

“…One effective method to enhance the CO tolerance is to generate discontinuous small size active sites instead of a large ensembles of nanoparticles in a crystal lattice. Single atom catalysts are the new class of materials which show surprising chemical properties to catalyze reactions which are not active for metal nanoparticles [237,238] . For example, iridium nanoparticle crystals are inactive for the FAO, but SAC of iridium supported on the nitrogen doped carbon catalyzed the FAO with a remarkable mass activity of 12.9 Amg −1 Ir whereas Ir/C shows negligible activity.…”

“…Single atom catalysts are the new class of materials which show surprising chemical properties to catalyze reactions which are not active for metal nanoparticles. [237,238] For example, iridium nanoparticle crystals are inactive for the FAO, but SAC of iridium supported on the nitrogen doped carbon catalyzed the FAO with a remarkable mass activity of 12.9 Amg À 1 Ir whereas Ir/C shows negligible activity. This remarkable activity could stem from the electronic effect of nitrogen doped carbon with single atom Ir and the spatial isolation of the Ir atoms.…”