Enhancing the electrocatalytic potential of trimetallic CeSmGd-MOFs for oxygen evolution reaction, supercapacitor, and dye degradation applications

Abstract

Developing multifunctional materials having a high electrocatalytic activity, superior energy storage capability, and efficient pollutant degradation efficiency is highly commendable for advancing sustainable energy and environmental technologies. A novel approach to develop two different trimetallic metal-organic frameworks has been developed by the solvothermal method.The synergistic effect of Cerium, Samarium, and Gadolinium with two different organic ligands, such as 2-NH 2 -1, 4-benzene dicarboxylic acid and 2,6-naphthalene dicarboxylic acid, has been assessed. The rod-like MOFs were further investigated by electrochemical analysis for oxygen evolution reaction (OER), supercapacitor application, and Congo Red dye degradation. For OER, CeSmGd-NDCA-MOF and CeSmGd-NH 2 -BDC-MOF exhibited overpotentials of 187 and 214 mV, respectively, with Tafel slopes of 50 and 63 mV/dec at current density of 10 mA/cm². The enhanced electrocatalytic OER performance of CeSmGd-NDCA-MOF is attributed to high electrochemical surface area of 1837.5 cm 2 , resulting in low charge transfer resistance (2.94 Ω cm - 2 ) and enhanced conductivity (2.04 Ω -1 cm -1 ). Furthermore, Supercapattery analysis of CeSmGd-NDCA-MOF and CeSmGd-NH 2 -BDC revealed that the former exhibited better activity, with a specific capacitance of 697.8 F/g at a scan rate of 5 mV/s and 771.4 F/g at a current density of 1 A/g, as calculated from CV and GCD, respectively, in 1M KOH. For electrochemical CR degradation, CeSmGd-NDCA-MOF revealed 95.23% efficiency at the applied potential of 0.1 V after 25 min (at pH: 7, CR concentration: 14 ppm, and 0.1 M KCl electrolyte) with energy consumption of 8.89 x 10 -4 kWh/m 3 and estimated cost of 4.30 x 10 -5 $.