Co/CoO/C@B three-phase composite derived from ZIF67 modified with NaBH 4 solution as the electrocatalyst for efficient oxygen evolution

Research progress on metal-organic framework compounds (MOFs) in electrocatalysis

Metal-organic frameworks (MOFs) have favorable characteristics such as large specific surface area, high porosity, structural diversity, and pore surface modification, giving them great potential for development and attractive prospects in the research area of modern materials electrocatalysis. However, unsatisfactory catalytic activity and poor electronic conductivity are the main challenges facing MOFs. This review focuses on MOF-based materials used in electrocatalysis, based on the types of catalytic reactions that have used MOF-based materials in recent years along with their applications, and also looks at some new electrocatalytic materials and their future development prospects.

Balancing Mass Transfer and Active Sites to Improve Electrocatalytic Oxygen Reduction by B,N Codoped C Nanoreactors

Mass transfer is critical in catalytic processes, especially when the reactions are facilitated by nanostructured catalysts. Strong efforts have been devoted to improving the efficacy and quantity of active sites, but often, mass transfer has not been well studied. Herein, we demonstrate the importance of mass transfer in the electrocatalytic oxygen reduction reaction (ORR) by tailoring the pore sizes. Using a confined-etching strategy, we fabricate boron- and nitrogen-doped carbon (B,N@C) electrocatalysts featuring abundant active sites but different porous structures. The ORR performance of these catalysts is found to correlate with diffusion of the reactant. The optimized B,N@C with trimodal-porous structures feature enhanced O₂ diffusion and better activity per heteroatomic site toward the ORR process. This work demonstrates the significance of the nanoarchitecture engineering of catalysts and sheds light on how to optimize structures featuring abundant active sites and enhanced mass transfer.

Hydrogenation of furfural to furfuryl alcohol over MOF-derived Fe/Cu@C and Fe3O4/Cu@C catalysts

With Cu-MOF-loaded Fe(NO3)3 as the precursor (Fe(NO3)3/Cu-MOF), Fe/Cu@C and Fe3O4/Cu@C catalysts were prepared from heating under the H2 and N2 atmosphere, respectively. When Fe(NO3)3/Cu-MOF was heated under different atmospheres, Cu-MOF...

p–d hybridization in CoFe LDH nanoflowers for efficient oxygen evolution electrocatalysis

Organic ligands can induce p–d orbital hybridization at the interface of CoFe LDH, resulting in a downshift of the d-band center of CoFe LDH and the optimization of the binding strength of intermediates during the OER.

In Situ Formation of Surface-Induced Oxygen Vacancies in Co9S8/CoO/NC as a Bifunctional Electrocatalyst for Improved Oxygen and Hydrogen Evolution Reactions

Creating oxygen vacancies and introducing heterostructures are two widely used strategies in Co-based oxides for their efficient electrocatalytic performance, yet both strategies have rarely been used together to design a bifunctional electrocatalyst for an efficient overall water splitting. Herein, we propose a facile strategy to synthesize oxygen-defect-rich Co9S8/CoO hetero-nanoparticles with a nitrogen-doped carbon shell (ODR-Co9S8/CoO/NC) through the in situ conversion of heterojunction along with surface-induced oxygen vacancies, simply via annealing the precursor Co3S4/Co(OH)2/ZIF-67. The as-prepared ODR-Co9S8/CoO/NC shows excellent bifunctional catalytic activities, featuring a low overpotential of 217 mV at 10 mA cm-2 in the oxygen evolution reaction (OER) and 160 mV at 10 mA cm-2 in the hydrogen evolution reaction (HER). This performance excellency is attributed to unique heterostructure and oxygen defects in Co9S8/CoO nanoparticles, the current work is expected to offer new insights to the design of cost-effective, noble-metal-free electrocatalysts.

Modulation of Disordered Coordination Degree Based on Surface Defective Metal-Organic Framework Derivatives toward Boosting Oxygen Evolution Electrocatalysis

Seeking potential electrocatalysts with both large-scale application and robust activity for the oxygen evolution reaction allows for no delay. Herein, a squarate-based metal-organic framework (MOF) ([Co₃ (C₄ O₄ )₂ (OH)₂ ]⋅3H₂ O) is reported for electrocatalytic water oxidation. A facile, green, and low-cost strategy is proposed to introduce defects by not only rationally breaking CoO bonds to form defective coordination environment and electronic reconfiguration, but also systematically modulates defect concentration to optimize electrochemical performance. As a result, the post-treated surface defective MOF derivative (Co-MOF-3h) achieves a current density of 50 mA cm^-2 at an overpotential of 380 mV, owing to larger active surface area, more opened active sites, and favorable conducting channels. Finally, density functional theory calculations have further validated the effect of defective coordination in regard to electronic structure for electrocatalysts. This study delivers inspirations in defect engineering and is in favor of developing high-efficiency electrocatalysts.

In Situ Growth of CoP3 /Carbon Polyhedron/CoO/NF Nanoarrays as Binder-Free Anode for Lithium-Ion Batteries with Enhanced Specific Capacity

Advanced functional materials enable lithium-ion batteries to reach high specific capacity. To achieve this goal, nickel foam (NF), as current collector, is chosen to in situ form aligned nanoarrays composed of CoP₃ /carbon polyhedron (CP)/CoO. The CoO nanowire acts as bridge to link NF and CoP₃ /CP which not only reinforces the adhesion between active material and NF but also enhances the capacity of whole electrode. Besides, CoP₃ is evenly coupled with CP, which can effectively buffer the volume expansion of CoP₃ during the charge/discharge process. Moreover, the novel architecture of CoP₃ /CP/CoO/NF is beneficial to improve the electronic conductivity. As a result, the CoP₃ /CP/CoO/NF anode delivers an ultrahigh specific capacity of 1715 mAh g^-1 at 0.5 A g^-1 which can remain at 1150 mAh g^-1 after 80 cycles, demonstrating the good durability. Thus, this work develops a facile strategy to design self-supporting electrodes for an enhanced energy storage device.

MOF based on a longer linear ligand: electrochemical performance, reaction kinetics, and use as a novel anode material for sodium-ion batteries

A novel longer linear ligand based MOF for SIBs.