A Highly‐Efficient Oxygen Evolution Electrocatalyst Derived from a Metal‐Organic Framework and Ketjenblack Carbon Material

Abstract

The composite of the metal‐organic framework (MOF) Ni(Fe)‐MOF‐74 and the highly conductive carbon material ketjenblack (KB) could be easily obtained from the in‐situ MOF synthesis in a one‐step solvothermal reaction. The composite material features a remarkable electrochemical oxygen evolution reaction (OER) performance where the overpotential at 10 mA/cm2 and the current density at 1.7 VRHE are recorded as 0.274 VRHE and 650 mA/cm2, respectively, in 1 mol/L KOH. In particular, the activation of nickel‐iron clusters from the MOF under an applied anodic bias steadily boosts the OER performance. Although Ni(Fe)‐MOF‐74 goes through some structural modification during the electrochemical measurements, the stabilized and optimized composite material shows excellent OER performance. This simple strategy to design highly‐efficient electrocatalysts, utilizing readily available precursors and carbon materials, will leverage the use of diverse metal‐organic complexes into electrode fabrication with a high energy conversion efficiency.

Nickel-Based Metal-Organic Frameworks as Electrocatalysts for the Oxygen Evolution Reaction (OER)

“…The bimodal pore size distribution of Ni 10 Co-BTC/KB with maxima at ~2 nm and ~4 nm reflects the contributions from the MOF and KB. Consequently, the BET surface area and pore volume of the Ni 10 Co-BTC/KB composite with 596 m 2 /g and 0.45 cm 3 /g, respectively, are higher than the surface area and pore volume of neat Ni 10 Co-BTC (303 m 2 /g, 0.15 cm 3 /g) but still lower than the calculated BET surface area (670 m 2 /g) as determined from the sum of the mass-weighted S(BET) of KB (33 wt.%) and MOF (67 wt.%) (Equation (3) [34]):…”

“…MOFs have been investigated as electrocatalysts due to their high porosity, large surface areas, diversity of composition and structure [27,[30][31][32][33]. MOFs can be used directly for electrocatalytic reactions, but they have drawbacks like (i) low electrical conductivity, (ii) mass transport problems of reactants, products and electrolyte ions through their micropores, (iii) lack of stability especially in highly acidic or alkaline aqueous environments [34]. Because of those drawbacks, MOFs are often employed as precursors or sacrificial agents to construct structured carbon-based metal oxide materials as efficient electrocatalysts [27,32,35].…”

“…The performance of Ni-MOF electrocatalysts could be enhanced by the introduction of a second metal such as cobalt or iron [35,[38][39][40][41]. Our previous work has shown that a Ni(Fe)-MOF/KB composite exhibited remarkable OER performance [34]. The MOF Ni-BTC and Ni(Fe)-BTC (BTC = 1,3,5-benzenetricarboxylate) have a fast charge transfer rate and high activity for the OER [40,42].…”

Formation of Gold Nanoclusters from Goldcarbonyl Chloride inside the Metal-Organic Framework HKUST-1

“…Metal-organic frameworks (MOFs) [ 1 , 2 , 3 , 4 ] are potentially porous and mostly crystalline three-dimensional solids, which attract considerable attention in a wide range of envisioned applications [ 5 ], e.g., in catalysis [ 6 ], hydrogen storage [ 7 ], separations [ 8 ], as sensors [ 9 , 10 , 11 ], for nanocluster formation [ 12 , 13 ], or precursors for electrocatalysts [ 12 , 14 , 15 ]. Open metal sites (OMSs), also named coordinatively unsaturated metal sites (CUSs), at the metal center possess a crucial role in some applications [ 16 , 17 , 18 ].…”

Synthesis of Ketjenblack Decorated Pillared Ni(Fe) Metal-Organic Frameworks as Precursor Electrocatalysts for Enhancing the Oxygen Evolution Reaction

“…Currently, there are various reports about MOFs and nanoparticles with Ketjenblack carbon which were used as catalysts for OER. [34,37,45,46,47,48] For instance, Sondermann et al [37] showed that the bimetallic Ni10Co-BTC/KB composite gave an overpotential of 344 mV at a current density of 10 mA cm -2 and a Tafel slope of 47 mV dec -1 in 1 mol L -1 KOH. Öztürk et al [48] reported Ni(Fe)-MOF-74 with KB for OER in an alkaline media.…”