Theoretical insight into hydroxyl production via H₂O₂ decomposition over the Fe₃O₄(311) surface

Abstract

Fenton's reagent provides a method to produce active hydroxyl radicals (˙OH) for chemical oxidation by mixing iron oxide and hydrogen peroxide, which divides into homogeneous and heterogeneous Fenton's reagent.

Melem Nanorectangular Prism-Modified {Mo72Fe30} Nanocapsule as a Visible-Light-Assisted Photocatalyst for Catalase-Like Activity

“…In the first step, the replacement of H 2 O molecules ligated to Fe 3+ centers by H 2 O 2 molecules followed by the protonation of NH 2 groups of Melem as proton scavengers, generates a Fe-OOH intermediate, although some contribution of bridged μ-oxygen (Fe–O–Mo bonds) and terminal oxygen (MoO) could exist. The larger activation energy of O–O bond scission, which produces OH groups, rather than the deprotonation of Fe-OOH as well as the lack of OH radicals in the reaction mixture, as evidenced by scavenging experiments, supports this process . The interaction of the second H 2 O 2 with Fe-OOH and protonated amines of Melem gives rise to O–O bond breaking in H 2 O 2 in a slow step, producing the H 2 O and O 2 molecules and regenerating the starting catalyst .…”

“…The larger activation energy of O−O bond scission, which produces OH groups, rather than the deprotonation of Fe-OOH as well as the lack of OH radicals in the reaction mixture, as evidenced by scavenging experiments, supports this process. 102 The interaction of the second H 2 O 2 with Fe-OOH and protonated amines of Melem gives rise to O−O bond breaking in H 2 O 2 in a slow step, 102 producing the H 2 O and O 2 molecules and regenerating the starting catalyst. 103 The protonated −NH 2 groups on the Scheme 2.…”

Mechanistic Impacts of Metal Site and Solvent Identities for Alkene Oxidation over Carboxylate Fe and Cr Metal–Organic Frameworks

“…However, experimentally determining adsorption–desorption equilibrium constants for these species at reaction conditions in the liquid phase is challenging because of either adsorbate reactivity (H 2 O 2 ) or the need for dry conditions (MeCN, MeOH) to minimize confoundment by water presence and competition for adsorption sites. DFT calculations are utilized instead to determine relative adsorbate binding energies of single H 2 O 2 , water, MeCN, and MeOH molecules that interact through their O or N heteroatoms with open penta-coordinated Fe or Cr sites contained within a truncated trimer cluster model (Figure ); calculated binding energies are higher than reported literature values due to the utilized combination of CP2K hyperparameters that are rationalized in the Supporting Information, though binding trends are consistent with literature precedent. − All adsorbates prefer conformations that enable hydrogen-bonding interactions with nearby ligand O atoms. Formate ligands are utilized in lieu of full benzoate ligands based on literature precedent. ,, The total electronic binding energy ( E binding = E ads – E trimer – E free ) of H 2 O 2 to Fe­(III) or Cr­(III) sites is found to exceed those of MeOH followed by MeCN and water (Table ).…”

Tetrahedral Keggin Core Tunes the Visible Light-Assisted Catalase-Like Activity of Icosahedral Keplerate Shell

“…The Raman intensities of the bands at 440 and 708 cm −1 , assigned to the Hg-mode of the {Mo 72 Fe 30 } capsule and the stretching vibration of the Fe−O−Mo bond, respectively, were reduced, 60 most likely caused by the interaction of Fe−O−Mo bonds with H 2 O 2 and protonation of the bridged μ-O oxygen. The larger activation energy of O− O bond scission which produces OH groups than that of deprotonation of coordinated H 2 O 2 79 and the lack of OH radicals in the reaction mixture (proved by scavenging experiments) support this process.…”

“…In the following steps, the absorption of the second H 2 O 2 followed by the interaction with the active Fe−OOH species and protonated bridged μ-O oxygen gives rise to O−O bond breaking of H 2 O 2 in a slow step, 79 producing water and O 2 molecules and regenerating the starting catalyst. 61 Thus, the mechanism does not require simultaneous involvement of two H 2 O 2 molecules in agreement with kinetic results, in which the reaction is apparently first-order on H 2 O 2 (vide supra).…”