Synergistic effects of platinum-bismuth nanoalloys on reduced graphene oxide for superior methanol and ethanol oxidation in acidic medium

• Published in: International journal of hydrogen energy Vol. 81; pp. 471 - 480
• Main Authors: Sekhar, Yellatur Chandra, Vinothkumar, Venkatachalam, Rao, H. Seshagiri, Sarma, Loka Subramanyam, Oh, Juwon, Kim, Tae Hyun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 04-09-2024
• Subjects: Acidic medium; Direct alcohol fuel cells; Ethanol oxidation; Methanol oxidation; Pt-Bi nanoalloy; Reduced graphene oxide; Ethanol oxidation; Reduced graphene oxide; Pt-Bi nanoalloy; Methanol oxidation; Direct alcohol fuel cells; Acidic medium
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2024.07.334

Efficient electrocatalysts are critical in the advancement of fuel cell technologies and should have superior activity for alcohol oxidation reactions (AORs). Herein, we report a facile one-pot method to synthesize platinum-bismuth nanoalloy (Pt–Bi) on reduced graphene oxide (RGO), enacting the methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) in an acidic solution. The reduction of the Pt and Bi precursors is co-mediated via l-ascorbic acid and ethylene glycol (EG) to afford Pt–Bi nanoparticles with an average size of 5.6 nm highly dispersed on the surface of RGO. Pt–Bi nanoparticle decoration is confirmed by transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX). X-ray photoelectron spectroscopy (XPS) results show the existence of the Pt–Bi metallic phase with minimal oxide. Electrochemical experiments using cyclic voltammetry (CV) reveal that the Pt–Bi/RGO catalyst is considerably more active than commercial Pt/C for AORs. Notably, the mass activity (Jmass) of MOR is enhanced by 1.3-fold and EOR is enhanced by 2.3-fold, highlighting the influence of the Pt–Bi interfacial concept. Overall, the results suggest that Pt–Bi/RGO is a highly promising candidate for use in direct alcohol fuel cells.
Schematic representation of the Pt–Bi/RGO electrocatalyst for methanol and ethanol direct oxidation reactions. [Display omitted]
•Pt–Bi alloy on RGO synthesized successfully by a one-pot method.•Pt–Bi/RGO provides more active sites for methanol and ethanol electro-oxidation.•Bi enhances Pt–Bi nanoparticle CO tolerance for alcohol oxidation.•Pt–Bi/RGO shows mass activity of 0.458 and 0.384 mA μg⁻1-Pt for MOR and EOR.•Improved catalyst stability and activity due to Pt–Bi synergy on RGO support.