Amorphous Metal–Organic Framework‐Dominated Nanocomposites with Both Compositional and Structural Heterogeneity for Oxygen Evolution

Abstract

Amorphous metal–organic frameworks (aMOFs) are an emerging family of attractive materials with great application potential, however aMOFs are usually prepared under harsh conditions and aMOFs with complex compositions and structures are rarely reported. In this work, an aMOF‐dominated nanocomposite (aMOF‐NC) with both structural and compositional complexity has been synthesized using a facile approach. A ligand‐competition amorphization mechanism is proposed based on experimental and density functional theory calculation results. The aMOF‐NC possesses a core–shell nanorod@nanosheet architecture, including a Fe‐rich Fe‐Co‐aMOF core and a Co‐rich Fe‐Co‐aMOF shell in the core–shell structured nanorod, and amorphous Co(OH)2 nanosheets as the outer layer. Benefiting from the structural and compositional heterogeneity, the aMOF‐NC demonstrates an excellent oxygen evolution reaction activity with a low overpotential of 249 mV at 10.0 mA cm−2 and Tafel slope of 39.5 mV dec−1.

Amorphous Metal–Organic Framework‐Dominated Nanocomposites with Both Compositional and Structural Heterogeneity for Oxygen Evolution

“…To characterize the structural difference,t he X-ray diffraction (XRD) patterns of cMIL-88B, aMIL-88B,a nd aMOF-NC were recorded. As shown in Figure 3a,t he diffraction peaks of cMIL-88B are in perfect match with the simulated patterns, [32] indicating high crystallinity.A fter treatment by 2-MeIM, the crystalline peaks disappeared, suggesting amorphization of MIL-88B.A fter introducing Co 2+ and the growth of nanosheets on aMIL-88B,s till no crystalline peaks can be found in aMOF-NC,c onsistent with the SAED observation. TheF ourier transform infrared (FTIR) spectra of three samples are presented in the Supporting Information, Figure S6, showing the presence of aminoterephthalate (donated as ATA) retained in aMIL-88B and aMOF-NC.N op eaks associated with 2-MeIM were found.…”

Ternary MOF-on-MOF heterostructures with controllable architectural and compositional complexity via multiple selective assembly

“…As an important family of porous crystalline materials, the composition and architecture of metal-organic frameworks (MOFs) are both key factors for their properties and applications 13 – 19 . To improve the complexity of MOF-based composites with broadened functions, the assembly of MOFs and other nanomaterials is a promising approach 20 – 23 . Meanwhile, conjugation of two or more different MOFs into one MOF-on-MOF hybrid material presents another strategy for the fabrication of complicated MOF hybrids with unprecedented nanostructures 24 – 35 .…”

Induced CO2 Electroreduction to Formic Acid on Metal−Organic Frameworks via Node Doping

“…The surface area (S BET ) of ZIF-8 reaches 1440 m 2 /g, in agreement with the previous reports well. [20,26] Sn 2 + competitive coordination may generate substantive amorphous phase defects in xSZ catalysts, [27] resulting in the higher S BET values of 1638-2193 m 2 / g (Table S2). The catalysts 0.4SZ and 0.6SZ exhibit the maximum surface areas of 2193 and 2011 m 2 /g, which are much higher than that of 0.8SZ (1681 m 2 /g), implying that excessive Sn introduction may destroy partial framework structures and cause the decreased surface area.…”