Electrochemical Characteristics of Magnesium–Aluminum Layered Double Hydroxide/Reduced Graphene Oxide Nanohybrids

This study investigates the efficiency of layered double hydroxide (MgAl-LDH) intercalated with reduced graphene oxide (rGO) composites as electrocatalyst for the hydrogen evolution reaction (HER) and provides insights into the HER mechanism using these composites.

Abstract

Magnesium–aluminum layered double hydroxide (MgAl-LDH) exhibits potential for energy applications; nevertheless, its use is compromised by inadequate conductivity. This study mitigates this constraint by synthesizing MgAl-LDH/reduced graphene oxide (rGO) nanohybrids with different LDH/rGO ratios (0.25, 0.5, and 0.75) to improve the electrocatalytic hydrogen evolution process (HER). Thorough characterization using XRD, SEM, EDS, XPS, and BET validated the successful incorporation of rGO into the LDH matrix, demonstrating a 2D/2D hybrid morphology with uniform elemental distribution and improved electronic interactions. Electrochemical assessments revealed that the LDH/rGO (0.25) composite displayed exceptional hydrogen evolution reaction (HER) performance, attaining the minimal overpotential (−434.82 mV at 10 mA/cm²) and a Tafel slope of −298.93 mV/dec, suggesting a Volmer–Heyrovsky mechanism. Notwithstanding the elevated charge transfer resistance (488.18 Ω·cm²), the composite exhibited 86.3% stability after 1000 cycles, owing to nitrogen doping in rGO and the synergistic electron transfer between LDH and rGO. This study highlights the promise of LDH/rGO hybrids as economical and effective catalysts for the hydrogen evolution reaction (HER), providing insights into the optimization of nanomaterial design for energy conversion technologies.

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