Ferrocene‐Based Metal–Organic Framework Nanosheets as a Robust Oxygen Evolution Catalyst

Abstract

We report the synthesis of two-dimensional metalorganic frameworks (MOFs) on nickel foam (NF) by assembling nickel chloride hexahydrate and 1,1'-ferrocenedicarboxylic acid (NiFc-MOF/NF). The NiFc-MOF/NF exhibits superior oxygen evolution reaction (OER) performance with an overpotential of 195 mV and 241 mV at 10 and 100 mA cm À2 , respectively under alkaline conditions. Electrochemical results demonstrate that the superb OER performance originates from the ferrocene units that serve as efficient electron transfer intermediates. Density functional theory calculations reveal that the ferrocene units within the MOF crystalline structure enhance the overall electron transfer capacity, thereby leading to a theoretical overpotential of 0.52 eV, which is lower than that (0.81 eV) of the state-of-the-art NiFe double hydroxides.

Highly Efficient and Simultaneous Removal of Cr(VI) and Imidacloprid through a Ferrocene-Modified MIL-100(Fe) Composite from an Aqueous Solution

“…At the same time, ICP-AES was used to detect the total Cr concentration when the solution turned light blue, and the residual of Cr(VI) was surveyed via UV−vis after the addition of chromogenic reagents; therefore, the presence of Cr(III) at this time was confirmed (Figure S2c). Cr(VI) shows a high redox potential (E 0 = 1.33 V vs SHE) and can react with Fe(II) in ferrocene at suitable pH values as follows: 26 Thus, MIL-100(Fe) modified by ferrocene not only maintains the microporous structure of MIL-100(Fe) 29 but also has reversible reducibility because of the role of Fe(II) in the ferrocene group. The existence of Cr(III) was also demonstrated by the next XPS experiment.…”

Metal–Organic Frameworks with Assembled Bifunctional Microreactor for Charge Modulation and Strain Generation toward Enhanced Oxygen Electrocatalysis

“…As shown in Figure 4d, the featured peaks between 532.2 and 532.8 eV highlighted by yellow and gray patterns could be ascribed to the hybridization between unoccupied oxygen 2p orbitals and cobalt 3d orbitals. 36 Compared with CoBDC and CoBDC BA, the feature peak located at ∼532 eV of CoBDC FcCA nanosheets became weaker, and the feature peak located at ∼533 eV of CoBDC FcCA nanosheets became stronger, attributable to the filling of the t 2g orbitals by the electrons in e g orbitals induced by the introduction of FcCA linkers. 36,37 This result was further supported by UV−vis diffuse reflectance spectra (UV−vis DRS, Figure 4e), in which the absorbance peaks of CoBDC FcCA nanosheets over 540− 570 nm red-shifted compared with those of CoBDC and CoBDC BA, confirming the electron transition from t 2g to e g .…”

Cu-Doped Layered Double Hydroxide Constructs the Performance-Enhanced Supercapacitor Via Band Gap Reduction and Defect Triggering

“…Conversely, the local DOS values across the Fermi level of CuCo-LDH increased obviously because of the Cu introduction, presenting a conductor-like electronic structure. 30 The obviously increased DOS values can enrich active sites, improve carrier concentration, and facilitate charge transfer. Therefore, introduction of the Cu atom into the Co-LDH structure is an effective strategy to modify the electronic properties and will pave the way for constructing high electrochemical active layered double hydroxide electrode materials.…”