MOF-Derived Cobalt@Mesoporous Carbon as Electrocatalysts for Oxygen Evolution Reaction: Impact of Organic Linker

Abstract

Water electrolysis has attracted scientists' attention as a green route for energy generation. However, the sluggish kinetics of oxygen evolution reaction (OER) remarkably increases the reaction overpotential. In this work, we developed Co-based nanomaterials as cost-effective, highly efficient catalysts for OER. In this regard, different Co-based metal−organic frameworks (MOFs) were synthesized using different organic linkers. After annealing under inert atmosphere, the corresponding Co-embedded mesoporous carbon (Co/MC) materials were produced. Among them, Co/MC synthesized using 2-methyl imidazole (Co/NMC-2MeIM) expressed the highest surface area (412 m 2 /g) compared to its counterparts. Furthermore, it expressed a higher degree of defects as depicted by Raman spectra. Co/NMC-2MeIM exhibited the best catalytic performance toward OER in alkaline medium. It afforded an overpotential of 292 mV at a current density of 10 mA cm −2 and a Tafel slope of 99.2 mV dec −1 . The superior electrocatalytic performance of Co/NMC-2MeIM is attributed to its high content of Co 3+ on the surface, high surface area, and enhanced electrical conductivity induced by nitrogen doping. Furthermore, its high content of pyridinic-N and high degree of defects remarkably enhance the charge transfer between the adsorbed oxygen species and the active sites. These results may pave the avenue toward further investigation of metal/carbon materials in a wide range of electrocatalytic applications.

Electrocatalytic activity and surface oxide reconstruction of bimetallic iron–cobalt nanocarbide electrocatalysts for the oxygen evolution reaction

“…4a, three Co species were identified: Co 0 (778 eV 2p 3/2 ), Co 2+ (780–786 eV 2p 3/2 ), and Co 3+ (779–785 eV 2p 3/2 ), indicative of the carbide and mixed valence oxide surface species, respectively. 64 The observed Co 2+ and Co 3+ species observed in as-synthesized samples are consistent with finding from Mullins and coworkers, 21 suggesting the presence of a thin-layer amorphous oxide on the surface. In particular, the evidence of a broadened 2p 3/2 peak at ∼795 eV is indicative of the presence of a spinel Co 3 O 4 compound, which is in agreement with our result from post-OER pXRD analysis ( vide infra ).…”

Carbon core–shell Pt nanoparticle embedded porphyrin Co-MOF derived N-doped porous carbon for the alkaline AEM water electrolyzer application

“…No significant difference was observed before and after electrochemical analysis, suggesting that the carbon nature did not change much during the HER. 76 Similarly, Fig. S16(e) (ESI†) confirms the existence of nitrogen in the electrocatalysts after the stability test.…”

Multiprocessing Substrates Enhanced Ta2O5/NiCo2O4 Spinel Nanocomposites for Effective Electro-/Photocatalytic and Toxicological Effects via the Caenorhabditis elegans Model

“…The Co/NMC-2MeIM electrode showed notable OER performance with an overpotential of 292 mV and a Tafel slope value of 99.2 mV dec −1 at a current density of 10 mA cm −2 . 15 Similarly, Han et al studied the electrochemical activity of a mesoporous Ndoped NiFeS (Meso C-NiFeS) electrocatalyst, which showed the highest OER performance with an overpotential of 350 mV at 10 mA cm −2 and a lower Tafel slope value of 93 mV dec −1 16 On the other hand, ZnO-doped Ta x O y was produced by a magnetron-sputtering process used for enhanced antibacterial action toward Staphylococcus aureus effectively. Also, the Bi 2 O 3 /NiCo 2 O 4 composite was studied for its photocatalytic performance against methylene blue, RhB, and acetaminophen (AP), and it demonstrated better photocatalytic efficiencies of 91.10, 96.25, and 97%, respectively.…”

“…Aymen et al reported the synthesis of cobalt-supported mesoporous carbon-embedded 2-methyl imidazole (Co/NMC-2MeIM) via metal–organic frameworks (MOFs), and the OER electrodes were fabricated using the drop-cast technique on the surface of a glassy carbon electrode. The Co/NMC-2MeIM electrode showed notable OER performance with an overpotential of 292 mV and a Tafel slope value of 99.2 mV dec –1 at a current density of 10 mA cm –2 . Similarly, Han et al studied the electrochemical activity of a mesoporous N-doped NiFeS (Meso C-NiFeS) electrocatalyst, which showed the highest OER performance with an overpotential of 350 mV at 10 mA cm –2 and a lower Tafel slope value of 93 mV dec –1 On the other hand, ZnO-doped Ta x O y was produced by a magnetron-sputtering process used for enhanced antibacterial action toward Staphylococcus aureus effectively.…”