Impact of Iron in Three-Dimensional Co-MOF for Electrocatalytic Water Oxidation

Abstract

The integration of iron (Fe) into a cobalt metal− organic framework (Co-MOF) tunes the electronic structure of the parent MOF as well as enhances their electrocatalytic characteristics. By using pyrazine and hydrofluoric acid, we have synthesized threedimensional Co-MOF [CoFC 4 H 4 N 2 (SO 4 ) 0.5 ], (1), and Fe-MOF [FeFC 4 H 4 N 2 (SO 4 ) 0.5 ], (2), through a single-step solvothermal method. Further, a series of bimetallic (having both Co and Fe metal centers) MOFs [Co 1−x Fe x FC 4 H 4 N 2 (SO 4 ) 0.5 ] were synthesized with variable concentrations of Fe, and their electrocatalytic performances were analyzed. The optimized amount of Fe significantly impacted the electrocatalytic behavior of the bimetallic MOF toward water oxidation. Particularly, the Co 0.75 Fe 0.25 -MOF needs only 239 and 257 mV of overpotential to deliver 10 and 50 mA/cm 2 current density, respectively, in alkaline electrolytic conditions. The Co 0.75 Fe 0.25 -MOF shows a lower Tafel slope (42 mV/ dec.) among other bimetallic MOFs and even the commercial RuO 2 , and it has excellent durability (with ∼8 mV increases in overpotential after 18 h of electrolysis) and 97.05% Faradaic efficiency, which further evident its catalytic excellency. These findings explore the intrinsic properties of MOF-based electrocatalysts and prospect the suitability for future water electrolysis.

Isovalent anion-induced electrochemical activity of doped Co3V2O8 for oxygen evolution reaction application

“…For electrochemical experiments, the prepared sample was used as the working electrode, Pt mesh as the counter electrode, and a saturated Ag/AgCl electrode as the reference electrode. The Ag/AgCl potential was converted to the reversible hydrogen electrode (RHE) scale by the following equation: 31,32 where is the standard redox potential for the Ag/AgCl reference electrode.…”

NiSe2 Nanoparticles Encapsulated in N-Doped Carbon Matrix Derived from a One-Dimensional Ni-MOF: An Efficient and Sustained Electrocatalyst for Hydrogen Evolution Reaction

“…The carbon matrix obtained from the organic framework can act as a highly conductive network, promoting fast electron transfer . The various heteroatoms (such as N, O, S, and P) contained in the organic ligands can be directly doped into the carbon framework, which provides more active sites and creates a favorable environment for the growth of metal nanoparticles. − In particular, a 1D MOF precursor have uniform and monodisperse morphology, and their derived carbonaceous materials can afford a high surface area that corresponds to better electrocatalytic performances . Furthermore, selenylation of the MOFs precursor by following various synthetic routes (such as chemical vapor deposition (CVD), solvothermal technique) are widely accepted to synthesize a highly efficient MOFs-precursor-derived N-doped carbon (NC)-embedded metal selenides electrocatalyst for the electrochemical HER. ,, The good electrical conductivity and large surface area of the MOF-precursor-derived NC-embedded metal selenides, implying more catalytic active sites and better durability under harsh acidic conditions, dominates over non-MOF-derived pristine transition metal based electrocatalysts for water electrolysis to generate carbon-free energy carriers. , Particularly, the highly active HER electrocatalyst is more favorable in the acidic electrolytic medium .…”

Introducing a Synergistic Ligand Containing an Exotic Metal in Metal–Organic Framework Nanoarrays Enabling Superior Electrocatalytic Water Oxidation Performance

“…To unlock the mentioned issues, one effective strategy is to prepare multidimensional nano MOFs, − especially two-dimensional (2D) MOF nanosheets. − The surface of 2D MOF nanosheets includes massive unsaturated coordinated metal centers, which usually are regarded as active sites to drive the catalytic reaction. The other strategy is to construct MOF nanoarrays on a self-supporting conductive substrate ,,− such as cost-effective carbon cloth (MOF NAs/CC).…”