Improving the Electrocatalytic Activity of a Nickel‐Organic Framework toward the Oxygen Evolution Reaction through Vanadium Doping

Abstract

Metal‐organic frameworks (MOFs) have been considered as potential oxygen evolution reaction (OER) electrocatalysts owning to their ultra‐thin structure, adjustable composition, high surface area, and high porosity. Here, we designed and fabricated a vanadium‐doped nickel organic framework (V1−x−NixMOF) system by using a facile two‐step solvothermal method on nickel foam (NF). The doping of vanadium remarkably elevates the OER activity of V1−x−NixMOF, thus demonstrating better performance than the corresponding single metallic Ni‐MOF, NiV‐MOF and RuO2 catalysts at high current density (>400 mA cm−2). V0.09−Ni0.91MOF/NF provides a low overpotential of 235 mV and a small Tafel slope of 30.3 mV dec−1 at a current density of 10 mA cm−2. More importantly, a water‐splitting device assembled with Pt/C/NF and V0.09−Ni0.91MOF/NF as cathode and anode yielded a cell voltage of 1.96 V@1000 mA cm−2, thereby outperforming the‐state‐of‐the‐art RuO2(+)||Pt/C(−). Our work sheds new insight on preparing stable, efficient OER electrocatalysts and a promising method for designing various MOF‐based materials.

A water coordinated Ni complex and a 2D Ni-MOF: topology dependent highly enhanced electrocatalytic OER activity

“…Metal centres with non-coordination sites or coordinated with a labile ligand show an improved electrocatalytic OER activity since the hydroxyl group can easily access the catalytic centre. 37 Water coordination with the metal centre or the presence of a water molecule in the MOF lattice leads to enhanced electrocatalytic OER and HER activity. 41,48 Furthermore, MOFs with 2D sheet structures have been shown to exhibit strong OER activity upon combining with conducting substrates that could be attributed to the exposure of a non-coordination site or labile ligand coordination towards electrolytes.…”

“…33,34 Constructing hetero bimetallic MOFs, generation of non-coordinated metal sites, labile solvent coordination and engineering intermetallic distances are some of the other methods reported for improving the electrocatalytic activity of MOFs. [35][36][37][38][39][40][41][42][43][44][45][46][47][48] However, the clear design strategy and direct use of MOFs as efficient electrocatalysts are still in the early stages. Optimizing the electronic structure of the metal catalytic centre is the most straightforward method to modify the intrinsic properties of the catalyst including the electronic conductivity and reaction energy barrier.…”

Structure–property–performance relationship of vanadium- and manganese-based metal–organic frameworks and their derivatives for energy storage and conversion applications

“…8b(i)). 142 Their ndings suggested that V doping accelerated the charge transfer in Ni-MOF with an OER overpotential of 235 mV at 10 mA cm −2 current density in 1 M KOH (pH = 14). This electrocatalyst's unique 3D self-supported structure provides more active sites, leading to a synergistic effect between active sites during water splitting.…”

Enhancing the electrocatalytic OER activity of Co-MOFs through labile solvents coordination

“…[38][39][40][41][42][43] Varying the ligand spacer or doping modulates the electronic coupling between the metal centres and causes enhancement in the OER activity. [44][45][46] Integration of polyoxometalate with MOFs synergistically improves electrocatalytic activity. 47,48 MOF-derived metal oxides, selenide, and nitride nanoparticles show enhanced OER activity due to morphological and electronic structure modulation.…”