Different Growth Behavior of MOF‐on‐MOF Heterostructures to Enhance Oxygen Evolution

Abstract

The exploration of non-noble metal electrocatalysts with high catalytic activity and stability for oxygen evolution reaction (OER) has become particularly urgent. Here, FeNi-based Prussian blue analogues (PBAs) were obtained by adding different solvents, where PBA particles preferentially grew on the surface plane/edge of coordination polymer precursor (Ni-ABDC) with various polarities. This resulted in the formation of FeNi-PBAplane/edge morphologies, respectively. Notably, on account of more exposed PBAs, FeNi nanoparticles were uniformly supported on the porous N-doped carbon nanomaterials. Among them, the calcined FeNi-NC-800 underwent an interesting pre-activation process and exhibited a low overpotential of 281 mV at 10 mA cm À 2 and a small Tafel slope of 82 mV dec À 1 in 1.0 m KOH. This bimetallic sample showed superior OER activity and stability in comparison with control materials, which could be attributed to its abundant FeNi nanoparticles, high nitrogen content, large specific surface area, and synergistic effects between Fe and Ni atoms. In addition, relevant theoretical calculation on the optimal catalyst, FeNi-NC-800, further demonstrated its efficient OER performance with effective Fedoping in the Ni-based oxyhydroxides.

Hierarchical Superhydrophilic/Superaerophobic Ni(OH)2@NiFe-PBA Nanoarray Supported on Nickel Foam for Boosting the Oxygen Evolution Reaction

“…In addition, Raman spectroscopy was also conducted to analyze the composition of Ni(OH) 2 @NiFe-PBA. As depicted in Figure 2b, the signals presented at 2140 and 2175 cm −1 are ascribed to the vibration of the Fe III −C�N−Ni II structure in NiFe-PBA, 39 and the signal originated from β-Ni(OH) 2 are also detected. The peak observed around 519 cm −1 is associated with structural defects, 40 which increased significantly after the introduction of NiFe-PBA in the heterostructure.…”

Interfacial Engineering of Heterogeneous Reactions for MOF‐on‐MOF Heterostructures

“…SEM and TEM images of d) FeNi-PBA-W, e) FeNi-PBA-E, f) FeNi-PBA-M, g) FeNi-PBA-P. Reproduced with permission. [144] Copyright 2022, Wiley-VCH. Schematic illustrations of UiO-66 grown on the h) (10-10) and i) (10-12) crystal facets of MIL-96(Al).…”

“…Last but not least, external factors also exert an influence on MOF-on-MOF growth. [101][102][103]144,145] Thermodynamic and kinetic factors play a role in nucleation events, while reaction conditions such as temperature and pressure may further influence growth outcomes (Table 1). In our review, this comprehensive examination of internal and external factors provides a holistic understanding of the complexities involved in MOF-on-MOF growth and offers promising avenues for future research and exploration within the MOF-on-MOF family (Scheme 1).…”

Insights on MOF-derived metal–carbon nanostructures for oxygen evolution

“…Similarly, we designed a cube-on-plate integrated structure by assembling PBA cubes on Ni–ABDC (H 2 ABDC = 5-aminoisophthalic acid) nanostrips for the introduction of Fe species. 70 Surprisingly, the cube-like PBAs were located on the plane or the edge of Ni–ABDC rather than uniformly distributed across the entire surface of Ni–ABDC, a phenomenon controlled by the polarity of the solution. With the unique integrated structure and the FeNi 3 active phases, the prepared catalyst exhibited improved OER properties compared to the Ni–NC derived from Ni–ABDC.…”

“…Typically, MOF precursors serve as both the metal and ligand sources, facilitating the subsequent growth of secondary MOFs. By introducing external metal ions and/or ligands, a new MOF develops on the surface of the original MOF under specific conditions, forming intriguing integrated structures such as polyhedra on rods, 45 cubes on strips, 70 core–shell. 71 Our group has long been interested in designing and preparing novel MOFs, and accumulated numerous experience in the rational design and controllable growth of multi-component of MOF-on-MOF heterostructures.…”