Evolution of Ultrathin CoFe‐Nanomesh for Oxygen Evolution Reaction: From Slit Pores to Ink‐Bottle Pores
Year: 2024
Type: article
Abstract: The time‐dependent mechanism underlying the formation of Co 0.8 Fe 0.2 (OH) x ‐t nanomesh (nanomesh having 80 % Co and 20 % Fe, “t” represents materials synthesis time) has been identified towards the development of a highly effective catalyst for the oxygen evolution reaction (OER). Utilizing 2‐ethyl imidazole (2‐HEIM) as an etching reagent and the Ostwald ripening process enabled the evolution of nanomesh formation with a precise pore size of ink‐bottle shape. Characterization techniques, including N 2 ‐adsorption/desorption, and transmission electron microscopy (TEM) analyses, confirmed the evolution of pore structure from layered double hydroxide‐like structure to hierarchical slit‐pores to uniform ink‐bottle pores after 24 h of synthesis with limited pore shrinkage attributable to iron redeposition at the pore entrances. Atomic force microscopy (AFM) showed a gradual reduction in nanomesh thickness with an increase in synthesis time up to 24 h, indicative of successful exfoliation. The best catalyst (Co 0.8 Fe 0.2 (OH) x ‐24 h) was developed after 24 h of synthesis, having 3.8 nm ink‐bottle‐shaped pores on the basal plane of nanosheets with only 3–4 layers. Co 0.8 Fe 0.2 (OH) x ‐24 h nanomesh exhibited the best catalytic performance, characterized by a 330 mV overpotential, a mass activity of 309.1 A/g, and a turnover frequency of 2.28 s −1 . Furthermore, electrochemical impedance spectroscopy indicated a low charge transfer resistance (5.9 Ω) and pseudoresistance (35.3 Ω), highlighting efficient electron transfer at the electrode/electrolyte interface and enhanced oxygen evolution reaction kinetics, respectively. An increased electrochemical surface area (70.74 cm 2 ) and a high roughness factor of approximately 1010 underlined the importance of narrow mesopores in facilitating catalyst‐electrolyte interactions and improving mass transport. The best material demonstrated remarkable stability during 25 h of electrolysis with a high average current density of 14.5 mA/cm 2 . Hence, this research underscores the critical role of pore morphology in nanomeshes for optimizing catalytic performance and providing stability under vigorous gas evolution due to catalysis.
Source: Chemistry - An Asian Journal
Authors: Shashank Sharma, Amit Paul
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: bronze
Funders: Association of Medical Research Charities, Department of Science and Technology, Ministry of Science and Technology, India, Indian Institute of Science Education and Research Bhopal, Indian Institute of Technology Mandi, Indian Institute of Science Education and Research Mohali, Science and Engineering Research Board
Awards: G1738148176, G3211388033
OpenAlex ID: W4404136705