Pt1−xNix Alloy Nanoparticles Embedded in Self-Grown Carbon Nanofibers: Synthesis, Properties and Catalytic Activity in HER

Abstract

The development of new heterogeneous Pt-containing catalysts has retained its relevance over the past decades. The present paper describes the method to produce metal–carbon composites, Pt1−xNix/CNF, with an adjustable Pt/Ni ratio. The composites represent Pt1−xNix (x = 0.0–1.0) nanoparticles embedded within a structure of carbon nanofibers (CNF). The synthesis of the composites is based on a spontaneous disintegration of Pt1−xNix alloys in an ethylene-containing atmosphere with the formation of CNF. The initial Pt1−xNix alloys were prepared by thermolysis of multicomponent precursors. They possess a porous structure formed by fragments of 100–200 nm. As was shown by X-ray diffraction analysis, the crystal structure of the alloys containing 0–30 and 60–100 at.% Ni corresponds to a fcc lattice based on platinum (Fm-3m), while the Pt0.50Ni0.50 sample is an intermetallic compound with the tetragonal structure (P4/mmm). The impact of the Ni content in the Pt1−xNix samples on their activity in ethylene decomposition was studied as well. As was revealed, the efficiency of Pt1−xNix alloys in this process increases with the rise of Ni concentration. The composite samples were examined in an electrochemical hydrogen evolution reaction. The synthesized Pt1-xNix/CNF composites demonstrated superior activity if compared with the Pt/Vulcan commercial catalyst.