Interface Engineering of Co‐LDH@MOF Heterojunction in Highly Stable and Efficient Oxygen Evolution Reaction

Abstract

The electrochemical splitting of water into hydrogen and oxygen is considered one of the most promising approaches to generate clean and sustainable energy. However, the low efficiency of the oxygen evolution reaction (OER) acts as a bottleneck in the water splitting process. Herein, interface engineering heterojunctions between ZIF‐67 and layered double hydroxide (LDH) are designed to enhance the catalytic activity of the OER and the stability of Co‐LDH. The interface is built by the oxygen (O) of Co‐LDH and nitrogen (N) of the 2‐methylimidazole ligand in ZIF‐67, which modulates the local electronic structure of the catalytic active site. Density functional theory calculations demonstrate that the interfacial interaction can enhance the strength of the CoOout bond in Co‐LDH, which makes it easier to break the H‐Oout bond and results in a lower free energy change in the potential‐determining step at the heterointerface in the OER process. Therefore, the Co‐LDH@ZIF‐67 exhibits superior OER activity with a low overpotential of 187 mV at a current density of 10 mA cm−2 and long‐term electrochemical stability for more than 50 h. This finding provides a design direction for improving the catalytic activity of OER.

Layered Double Hydroxide Hollowcages with Adjustable Layer Spacing for High Performance Hybrid Supercapacitor

“…In order to elucidate the elemental composition and chemical valence of the samples before and after intercalation, X-ray photoelectron spectroscopy (XPS) analysis was performed on CoNi-LDH and CoNi-BDC-0.02. The survey spectra of Figure S9 [24] indicating that Co 2+ and Co 3+ exist in the samples and the valence state has not changed after intercalation. Furthermore, the high-resolution O 1s spectra of the two samples are depicted in Figure S10, Supporting Information.…”

“…As the reaction continues, the internal ZIF-67 becomes fragile and eventually forms hollow CoNi-LDH nanocages. [22][23][24] Finally, CoNi-BDC hollowcages are synthesized by the bonding of BDC ligand anions to the adjacent positively charged plane layer of CoNi-LDH through electrostatic interactions and hydrogen bonding. [20] The morphology of the prepared ZIF-67 nanocubes was characterized by a field emission scanning electron microscope (FESEM), as shown in Figure S1, Supporting Information.…”

Dynamics and control of active sites in hierarchically nanostructured cobalt phosphide/chalcogenide-based electrocatalysts for water splitting

“…First, ZIF-67 nanocubes (NCs) were synthesized at room temperature based on slightly modified protocols from previous reports [57][58][59][60] (Fig. 1a,…”

Electrodeposition of Defect‐Rich Ternary NiCoFe Layered Double Hydroxides: Fine Modulation of Co3+ for Highly Efficient Oxygen Evolution Reaction

“…[42] The two peaks at binding energies of 780.3 eV and 796.2 eV corresponded to the Co 3 + state, while the peaks at 782.5 eV and 798.1 eV were assigned to Co 2 + state. [43,44] Note that the Co 3 + /Co 2 + ratios of these three LDHs were significantly different. The proportion of Co 3 + among these LDHs followed the order of Ni(Co 0.5 Fe 0.5 )-bulk (56.1 %) < Ni(Co 0.5 Fe 0.5 )-mono (61.6 %) < Ni(Co 0.5 Fe 0.5 )/NF (66.3 %), as shown in Figure 3b.…”