Density Functional Theory Study of Water Dissociative Chemisorption on the Fe₃O₄(111) Surface

Abstract

Water dissociative chemisorption on the Fe oct-tet1 -terminated Fe 3 O 4 (111) surface was studied using periodic density functional theory (DFT) at both low and high water coverage. The active sites and adsorption patterns were identified, and the dissociation pathways and energetics were calculated. It was found that water can undergo dissociative chemisorption to form a surface hydroxyl group and a H atom with a favorable thermochemical energy and a moderate activation barrier at low coverage. This reaction can be readily catalyzed by water molecules around the active sites. We found that direct breakup of the hydroxyl group into H and O adatoms on the surface is energetically difficult and higher water coverage has an only modest effect on catalyzing the reaction. Our results are consistent with the kinetic and isotope exchange experiments.

A First-Principles Study of Oxygen Formation Over NiFe-Layered Double Hydroxides Surface

“…Reaction pathways and barriers were determined using the climbing-image nudged elastic band method (CI-NEB) [46]. The NiFe-LDH structure was optimized by using 400 eV as the cutoff energy for basis function [57]. The global break condition for the electronic SC-loop (total free energy change and band structure energy change) was set to 1 9 10 -5 .…”

A computational study on water adsorption on Cu2O(111) surfaces: The effects of coverage and oxygen defect

“…Further, water bridges the OH and H groups resulting in a unique type of H-bonded molecular water with its oxygen forming a hydronium-ion-like structure OH 3 + -OH. On the Fe 3 O 4 (1 1 1) surface, the less stable Fe oct2 termination (−1.11 eV) has stronger H 2 O molecular adsorption than the most stable Fe tet1 termination (−0.67 eV), and the Fe oct2 termination also has strong dissociative chemisorption energy (−1.33 eV) and is exothermic by 0.22 eV, and the dissociation barrier is 0.71 eV relative to the predissociation state [34]. For one water molecule adsorption on Fe tet1 termination of the Fe 3 O 4 (1 1 1) surface [35], both scanning tunneling microscopy (STM) and first-principle theoretical simulations show that dissociative adsorption is more stable than molecular adsorption, and the dissociation has low barrier.…”

Structure of the NiFe2O4(001) surface in contact with gaseous O2 and water vapor

“…In particular, NiFe 2 O 4 is a promising material for magnetic storage systems 2 , magnetic-resonance imaging 3 , spintronics 4,5 , etc. Recently, NiFe 2 O 4 has also attracted significant attention for its catalytic activity for the oxygen evolution reaction 6 , and as a potential catalyst for the Water Gas Shift (WGS) reaction 7 , where the reactivity is limited by water desorption 8 . The interaction of NiFe 2 O 4 surfaces with water plays a key role in all the applications of this material in catalysis.…”