In situ transformed three heteroleptic Co(II)-MOFs as potential electrocatalysts for the electrochemical oxygen evolution reaction. (1st November 2021)

• Record Type: Journal Article
• Authors: Singh, Durgesh; Raj, Krishna K.; Azad, Uday Pratap; Pandey, Rampal
• Is Part Of: Electrochimica acta. Volume 394(2021)
• Publication Date: 2021-11-01
• Subjects: Metal-organic framework -- Electrochemical Impedance -- Electrocatalysis -- Water oxidation; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.139117
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Re-synthesis of strategically chosen three Heteroleptic Co(II)-MOFs having 1D, 2D and 3D structures and different ligands. Detailed comparative electrocatalytic investigations of Co(II)-MOFs for oxygen evolution reactions based on morphology. Cyclic & Linear Sweep Voltammetry, Electrochemical Impedance, Chronoamperometry etc. & SEM, EDX, TEM and BET experiments. Materials showed electrocatalytic activity for OER that is comparable to superior to state of art catalysts IrO2 & Pt/C. MOFs bear high operational stability even after 1000 CV cycles thus could be suitable for commercial electrocatalysts. Abstract: Three Co(II)-MOFs, catena- [(diaqua-(μ2-bqdc-κO, O)-(phen-κN, N)-cobalt (II)] (1), {[Co(pa)(4, 4′-bipy)(H2O) (CH3OH)]DMF}n (2) and [Co(ia)(bpe)0.5(H2O)]n (3), (H2bqdc = 2, 2-biquinoline-4, 4′-dicarboxylic acid, phen = 1, 10-phenanthroline), (H2 pa = pamoic acid) (H2 ia = itaconic acid, bpe = 1, 2-bi(4-pyridyl)ethane) have been re-synthesized and thoroughly characterized by FT-IR, PXRD, SEM, EDX, HRTEM, BET surface area and UV/Vis techniques. The objective of choosing three Co(II)-MOFs 1 –3 composed of different ligands and having 1D, 2D and 3D structures, respectively, was to have deep insights into role of linked ligands and the structural morphology toward electrocatalytic performance. MOFs 1 –3 have been examined as electrocatalysts for water oxidation and comparative assessments revealed their catalytic performance in the order 2 > 3 ≈ 1 . MOF 2 shows the best electrocatalytic activity for OER, which could be due to the higher amount of cobalt present in MOF-2, faster electron transfer kinetics and higher effective electrode surface area. The onset potential of MOF 2 was comparable or less as compared to benchmark catalysts IrO2 and Pt/C. Overall studies strongly suggest that MOF 2 could be promising materials for replacement of commercial high-cost electrode material. Graphical abstract: Image, graphical abstract