Surface Reconstruction Facilitated by Fluorine Migration and Bimetallic Center in NiCo Bimetallic Fluoride Toward Oxygen Evolution Reaction.
Zhenhang XuWei ZuoYueying YuJinyan LiuGongzhen ChengPingping ZhaoPublished in: Advanced science (Weinheim, Baden-Wurttemberg, Germany) (2023)
Oxygen evolution reaction (OER) is a critical anodic reaction of electrochemical water splitting, developing a high-efficiency electrocatalyst is essential. Transition metal-based catalysts are much more cost-effective if comparable activities can be achieved. Among them, fluorides are rarely reported due to their low aqueous stability of coordination and low electric conductivity. Herein, a NiCo bimetallic fluoride with good crystallinity is designed and constructed, and significantly enhanced catalytic activity and conductivity are observed. The inevitable oxidation of transition metal ions at high potential and the dissociation of F - are attributed to the low aqueous stability of coordination. The theoretical researches predicte that transition metal fluorides should have a strong tendency to electrochemical reconstruction. Therefore, based on the observations on their electrochemical behavior, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and bode plots, it is further demonstrated that surface reconstruction occurred during the electrochemical process, meanwhile a significant increase of electrochemically active area, which is created by F migration, are also directly observed. Additionally, DFT calculation results show that the electronic structure of the catalysts is modulated by the bimetallic centers, and this reconstruction helps optimizing the adsorption energy of oxygen-containing species and improves OER activity.
Keyphrases
- transition metal
- electron transfer
- ionic liquid
- high resolution
- gold nanoparticles
- high efficiency
- metal organic framework
- electron microscopy
- molecularly imprinted
- label free
- drinking water
- magnetic resonance imaging
- aqueous solution
- wastewater treatment
- computed tomography
- climate change
- density functional theory
- pet imaging
- molecular dynamics simulations
- dual energy
- molecular dynamics