Novel NiCoMn–PDC MOFs: a dual-functional material for electrocatalytic water splitting and hybrid supercapacitor applications

Abstract

Addressing the global energy crisis needs advanced materials capable of both high-capacity energy storage and efficient electrocatalytic water splitting. Current technologies face challenges related to the low energy density of supercapacitors and sluggish reaction kinetics of the hydrogen evolution reaction and oxygen evolution reaction in water splitting. We hydrothermally synthesized a novel ternary Ni–Co–Mn metal–organic framework using 2,6-pyridine dicarboxylic acid as the organic ligand. As an electrocatalyst, the material achieves lower overpotentials of 47 mV for the hydrogen evolution reaction and 61 mV for the oxygen evolution reaction at a current density of 10 mA cm⁻², along with a Tafel slope of 60 mV dec⁻¹. For energy storage, it delivers specific capacitances of 1070 F g⁻¹ (CV, 2 mV s⁻¹) and 840 F g⁻¹ (GCD, 0.5 A g⁻¹) as well as a specific capacity of 420 C g⁻¹. The fabricated hybrid supercapacitor device exhibits a power density of 475 W kg⁻¹ and an energy density of 45 Wh kg⁻¹. Moreover, it showed a coulombic efficiency of 99.88% and stability of 79.01% after 5000 charge–discharge cycles. This work introduces a successful material design strategy by integrating high-capacity charge storage and superior electrocatalysis within a single MOF framework.