Cobalt-Based MOF-on-MOF Two-Dimensional Heterojunction Nanostructures for Enhanced Oxygen Evolution Reaction Electrocatalytic Activity

Abstract

Two-dimensional (2D) Co-based MOF-on-MOF heterojunction nanostructures with improved electrocatalytic activity were successfully constructed via a mild two-step solution route, employing Co2+ ions as the center atoms, and 1,4-benzenedicarboxylate (BDC) and 4,4′-biphenyldicarboxylate (BPDC) as ligands. The as-obtained heterojunction nanostructures were characterized by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) technologies. Electrochemical measurements showed that as-prepared Co-BPDC/Co-BDC heterojunction nanostructures presented markedly enhanced OER electrocatalytic activity, compared with single Co-BPDC, Co-BDC, and/or their physical mixture. Also, the Co-BPDC/Co-BDC-3 heterojunction prepared after treatment for 3 h exhibited the strongest catalytic activity. To reach the current density j geo = 10 mA cm–2, the Co-BPDC/Co-BDC-3 heterojunction-modified glassy carbon electrode required an overpotential of 335 mV in 1 M KOH, which was reduced by 57 and 93 mV, compared to the electrodes modified by Co-BDC and Co-BPDC, respectively. Simultaneously, the heterojunction catalyst also displayed better long-term stability. The improvement of the above performances should be attributed to the increased structure stability, BET surface area, ECSA, and electron transfer ability of the heterojunction.

Single‐Atom and Dual‐Atom Electrocatalysts Derived from Metal Organic Frameworks: Current Progress and Perspectives

“…This is a consequence of the transfer of electrons and protons, and the bonding interactions between these intermediates are crucial for catalytic activity. Too weak oxygen binding makes oxidation of HO* as a rate‐determining step, while too strong oxygen binding makes the formation of HOO* as a rate‐limiting step [88,89] . Therefore, it is of great significance to control the strength of oxygen bonding to promote the OER catalytic process.…”

“…Too weak oxygen binding makes oxidation of HO* as a rate-determining step, while too strong oxygen binding makes the formation of HOO* as a rate-limiting step. [88,89] Therefore, it is of great significance to control the strength of oxygen bonding to promote the OER catalytic process.…”

Recent Progress of Two‐Dimensional Metal‐Organic Frameworks and Their Derivatives for Oxygen Evolution Electrocatalysis

“…There are also reports focusing on the combination of heterogeneous components and 2D Co-based MOFs to optimize the electronic structure. [81][82][83] Such hybridization can also prevent MOF nanosheet agglomeration. For instance, Huang's group [81] incorporated 2D cobalt 1,4-benzenedicarboxylate (CoBDC) with Ti 3 C 2 T x nanosheets via an inter-diffusion reactionassisted process.…”

“…There are also reports focusing on the combination of heterogeneous components and 2D Co‐based MOFs to optimize the electronic structure [81–83] . Such hybridization can also prevent MOF nanosheet agglomeration.…”

Preparation of a Dual‐MOF Heterostructure (ZIF@MIL) for Enhanced Oxygen Evolution Reaction Activity

“…Many structures based on MOFs have been developed, for example, nanotubes, [11] core–shell structures, [12] and heterostructures [13] . Most importantly, such heterostructures have stimulated much research interest because more active sites are exposed, the charge transfer is enhanced, and synergy is promoted, [14] which can improve the application prospects of MOFs in electrocatalysis [15] . A heterostructured catalyst not only maintains the excellent properties of each component material, but also exhibits different performances from the individual components [16] .…”