One-pot synthesis of multifunctional ternary PtCuNi alloys: Magnetic properties and efficient hydrogen evolution reaction in alkaline media

Abstract

The development of efficient, recyclable and low-cost electrocatalysts represents a formidable challenge in the production of hydrogen gas for fuel cell technologies. Herein, we reported the catalytic and magnetic properties of multifunctional, low Pt-content ternary Pt21Cu55Ni24, Pt39Cu24Ni37, and Pt45Cu32Ni23 catalysts nanoparticles (NPs), which were synthesized using modified polyol process. X-ray diffraction and Rietveld refinement analysis confirmed the fcc-Fm3¯m space group, with the (111) facets being the most preferred planes and the Pt39Cu24Ni37 catalyst exhibiting the smallest crystal size of 1.75 ± 0.36 nm, the largest dislocation density of 356.16 nm−2 and micro strain of 43.21 × 10−3 a.u. for Pt39Cu24Ni37 catalyst. All NPs exhibited a uniform particle size distribution with an average size ranging between 2 nm and 4 nm. The Pt39Cu24Ni37 catalyst demonstrated excellent HER activity in 1 M KOH alkaline media at room temperature, with the lowest onset potential of 30.3 mV (vs. RHE), an overpotential value of -71.30 mV to achieve a current density of 10 mA cm−2, and the highest electrochemically active surface area of 39.45 m2 gPt−1. Stability tests conducted at a potential of 93.3 mV (vs. RHE) exhibited good stability for all samples. Additionally, Pt21Cu55Ni24, Pt39Cu24Ni37, and Pt45Cu32Ni23 catalysts followed the Volmer–Tafel HER mechanism with Tafel slopes of 49 mV dec−1, 50 mV dec−1 and 42 mV dec−1, respectively. The magnetic results obtained from M-H and M-T curves revealed that all three materials exhibit strong paramagnetic properties.