A Kinetic Control Strategy for One‐Pot Synthesis of Efficient Bimetallic Metal‐Organic Framework/Layered Double Hydroxide Heterojunction Oxygen Evolution Electrocatalysts

Abstract

Heterojunction materials are promising candidates for oxygen evolution reaction (OER) electrocatalysts to break the linear scaling relationship and lower the reaction barrier. However, the application of heterojunction materials is always hindered by the complicated multistep synthetic procedures which bring cost, complexity, and reproducibility issues. Herein, a strategy of kinetic controlled synthesis is developed to achieve the one-pot formation of bimetallic metal-organic framework (MOF)/layered double hydroxide (LDH) heterojunction electrodes as highly efficient OER electrocatalysts. The heterojunction electrodes present hierarchical structures with highly porous NiFe-LDH nanosheet networks vertically grown on the surface of NiFe-MOF-74 microprisms, promoting fast mass transport and high exposure of active sites. The strong interactions at the MOF/LDH heterojunction interfaces contribute to the outstanding OER activity surpassing the state-of-art RuO 2 OER catalysts. The MOF/LDH heterojunction electrode exhibits an ultralow overpotential of only 159.7 mV to reach the current density of 10 mA cm −2 , and yields large current densities at small overpotential (100 mA cm −2 at 230.2 mV and 1000 mA cm −2 at 284.3 mV) with long-term durability. This study presents an innovative approach to construct heterojunction materials with simple onestep synthesis, offering a promising pathway for high-efficiency electrocatalyst development.

Construction of an Advanced NiFe-LDH/MoS2–Ni3S2/NF Heterostructure Catalyst toward Efficient Electrocatalytic Overall Water Splitting

“…Among them, NiFe-LDH/MoS 2 –Ni 3 S 2 /NF affords a cell voltage of 1.50 V to achieve a current density of 10 mA cm –2 in comparison to those of MoS 2 –Ni 3 S 2 /NF (1.55 V), Ni 3 S 2 /NF (1.73 V), NiFe-LDH/NF (1.69 V), and RuO 2 /NF||Pt–C/NF (1.66 V), indicating that NiFe-LDH/MoS 2 –Ni 3 S 2 /NF has excellent overall water splitting performance, as shown in Figure b. Compared with other related overall water splitting electrocatalysts reported in recent years (see Figure c and Table ), the cell voltage of NiFe-LDH/MoS 2 –Ni 3 S 2 /NF is superior to those of numerous other reported transition metal NiFe-LDH and MoS 2 –Ni 3 S 2 -based as well as RuO 2 ||Pt–C electrocatalysts. − …”

Constructing MIL-53(Fe)@ZIF-67(Co) binary metal–organic framework hierarchical heterostructure electrodes for efficient oxygen evolution

“…47,48 To determine the rate-determining step and explore the real active site, the free energy of the intermediates (*OH, *O, and *OOH) of MIL-53(Fe) and MIL-53(Fe)@ZIF-67(Co) in the OER process was calculated using the DFT method. [48][49][50] The Gibbs free energy profiles in Fig. 5c and Fig.…”

Unusual Post Modulation of Pore Size, Nanostructure, and Composition of Metal–Organic Frameworks via Cooperative Ozone/Water Co‐Etching

“…Tailoring their structure, texture, and surface properties are crucial to enhance their OER performance. [24] The OER performances of the original ZIF-67, the calcined sample (450 °C, Co 3 O 4 ), and the typical etched samples by O 3 , H 2 O, and O 3 /H 2 O were compared (Figure 5 and Table 1). In the linear sweep voltammetry (LSV) curves (Figure 5a), at a current density of 10 mA cm −2 , the original ZIF-67 and calcined sample exhibit high overpotentials of 398 and 396 mV, while all the etched samples show lower values.…”