Engineered Pt-Pd@RGO-KI nanosheet catalyst for enhanced electrocatalytic methanol oxidation performance

Abstract

Electrocatalytic oxidation of methanol is crucial for the transition to clean energy and the effective utilization of renewable sources. The strategy to develop efficient electrocatalysts with improved efficiency and durability for the methanol oxidation (MOR) reaction is essential to enable the widespread usage of direct methanol fuel cells (DMFCs). This research proposes a novel, eco-friendly single-step procedure for preparing a highly efficient bimetallic platinum-palladium (Pt-Pd)/reduced graphene oxide-potassium iodide (RGO-KI) (PP@RGO-KI) nanocomposite sheet for electrocatalytic methanol oxidation. The method employs a chemical reduction strategy via a hydrothermal reaction, utilizing ascorbic acid (AA) as a simple and green reducing agent. The synergistic effects of Pt and Pd nanoparticles, along with enhanced electron transfer enabled by RGO, were examined by calculating the mass-normalized current densities (jmass) at 0.631 V for Pt/C, Pd/RGO, Pt-Pd/RGO (PP@RGO), Pt/RGO & PP@rGO-KI were 0.131, 0.171, 0.215, 0.421, and 0.526 mA/µg-Pt, respectively. Furthermore, the specific current densities (jspecific) at 0.631 V were determined as follows: 0.298 mA/cm² for Pd/RGO, 0.337 mA/cm² for Pt/C, 0.341 mA/cm² for Pt/RGO, 0.534 mA/cm² for PP@RGO, and 0.628 mA/cm² for PP@RGO-KI. In additionally, the If/Ib values exhibited the following trend: PP@RGO-KI (1.72) > PP@RGO (1.54) > Pt/RGO (1.04) > Pt/C (1.01) > Pd/RGO (0.89), signifying that PP@RGO-KI is effective in preventing surface poisoning effects. The excellent electrocatalytic efficiency of the PP@RGO-KI, coupled with its facile and rapid manufacturing method, suggests significant potential for advancing DMFCs. © 2024