Structural and Electrochemical Insights into Pt65Cu35 Alloy for Enhanced HER Performance

Abstract

This study presents a comprehensive structural and electrochemical characterization of Pt₆₅Cu₃₅ alloy nanoparticles (NPs) for their application in the hydrogen evolution reaction (HER). X-ray diffraction method have been used to determine structural properties and revealed a well-defined crystal structure corresponding to the face-centered-cubic (fcc) Pt₃Cu₁ alloy phase, evidenced by characteristic Miller indices as the (111), (200), (220), (311), and (222) planes. Further examination yielded a uniform lattice constants of 3.923 Å, indicating a homogeneous crystal lattice. Assessment of crystallite size, 2.9 nm, and microstrain, 3.85%, underscored the influence of PtCu alloy formation on structural defects and grain boundaries within the NPs. The stoichiometric calculation via energy-dispersive X-ray spectroscopy confirmed Pt and Cu ratio with a percentage of 65 and 35 in the structure and scanning electron microscope showed a spherical morphology attributed to the influence of polyvinylpyrrolidone molecules during synthesis. Moreover, electrochemical investigations revealed promising HER catalytic performance, with cyclic voltammetry (CV) analyses demonstrating Pt-H formation followed by H₂ gas formation. Linear sweep voltammetry (LSV) analysis confirmed a maximum current density of 1.52 mA cm^-2 was achieved at -0.37 V, indicating high catalytic activity. Furthermore, CV curves recorded over 500 cycles elucidated cyclic behavior, with a current density of 3.04 mA cm^-2 gradually decreasing over subsequent cycles before stabilizing beyond the 100th cycle. These findings underscore the exceptional electrocatalytic performance of Pt₆₅Cu₃₅ catalysts, highlighting their potential for various electrochemical applications. Further research avenues may focus on elucidating underlying mechanisms governing cyclic behavior to optimize catalyst design for enhanced performance and durability.