Elucidating the performance of hexamethylene tetra-amine interlinked bimetallic NiCo-MOF for efficient electrochemical hydrogen and oxygen evolution

• Published in: RSC advances Vol. 14; no. 2; pp. 13837 - 13849
• Main Authors: Zahid, Rida, Abdul Karim, Muhammad Ramzan, Khan, Fahd Sikandar, Marwat, Mohsin Ali
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 25-04-2024
• Subjects: Bimetals; Chemical synthesis; Current density; Electrocatalysts; Electrochemical analysis; Hydrogen; Hydrogen evolution; Intermetallic compounds; Metal-organic frameworks; Oxygen evolution reactions; Reaction kinetics; Tafel slopes; Water splitting
• DOI: 10.1039/d4ra00340c
• EISSN: 2046-2069

Bimetallic metal-organic frameworks (MOFs) play a significant role in the electrocatalysis of water due to their large surface area and availability of increased numbers of pores. For the inaugural time, we examine the effectiveness of a hexamethylene tetra-amine (HMT)-induced 3D NiCo-MOF-based nanostructure as a potent bifunctional electrocatalyst with superior performance for overall water splitting in alkaline environments. The structural, morphological, and electrochemical properties of the as-synthesized bifunctional catalyst were examined thoroughly before analyzing its behavior towards electrochemical water splitting. The HMT-based NiCo-MOF demonstrated small overpotential values of 274 mV and 330 mV in reaching a maximum current density of 30 mA cm
−2
for hydrogen and oxygen evolution mechanisms, respectively. The Tafel parameter also showed favorable HER/OER reaction kinetics, with slopes of 78 mV dec
−1
and 86 mV dec
−1
determined during the electrochemical evaluation. Remarkably, the NiCo-HMT electrode exhibited a double-layer capacitance of 4 mF cm
2
for hydrogen evolution and 23 mF cm
−2
for oxygen evolution, while maintaining remarkable stability even after continuous operation for 20 hours. This research offers a valuable blueprint for implementing a cost-effective and durable MOF-based bifunctional catalytic system that has proven to be effective for complete water splitting. Decomposition of water under higher current densities is crucial for effective long-term generation and commercial consumption of hydrogen.
This study investigates the electrocatalytic water splitting capabilities of hexamethylene tetra-amine-linked NiCo-MOF, synthesized
via
hydrothermal approach. It reveals low overpotentials of 274 mV and 330 mV with Tafel slopes of 78 mV dec
−1
and 86 mV dec
−1
towards HER and OER respectively.