Disentangling element‑specific pathways in solvothermal formation of platinum-group metal complex solid solutions
Year: 2026
Type: preprint
Abstract: Platinum‑group metal (PGM) complex solid‑solution nanoparticles exhibit unique catalytic properties due to a homogeneous atomic‑scale distribution of multiple elements within a single crystalline phase. Despite their importance, the mechanisms governing their solvothermal formation remain poorly understood. Here, we investigate the solvothermal synthesis of multicomponent Pt–Ir–Pd–Rh–Ru nanoparticles by in situ powder X‑ray diffraction, enabling time‑resolved monitoring across a wide compositional space of ternary and quaternary alloys. Lattice‑parameter evolution confirms incorporation of all elements into a common fcc phase with a systematic iridium deficiency. Crystallite size correlates with elemental heat of fusion, identifying lattice energy as a key parameter controlling particle growth. Formation pathways are strongly element specific: Pd‑free systems form homogeneous alloys directly, whereas Pd‑containing systems follow a two‑step mechanism involving initial Pd‑rich crystallisation and diffusion‑controlled alloying when Pt is present. Pd without Pt yields inhomogeneous multiphase products, contradicting the assumption that Pd seeding is required for homogeneous PGM alloy formation. Overall, this study demonstrates how in situ X‑ray diffraction can accelerate materials discovery while also providing general mechanistic insight into multicomponent solvothermal alloy formation.
Source: ChemRxiv
Institution: Aarhus University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213451739