Synthesis and Fingerprint of a Fully Coalescent, High-Quality Epitaxial Co 9 S 8 –CoS 2 Thin Film

Year: 2026

Type: article

Abstract: Cobalt sulfide (Co–S) phases are of significant interest for energy conversion and sensing technologies due to their combined catalytic activity and electronic conductivity. In particular, Co 9 S 8 is a promising precatalyst for oxygen evolution reaction, but its synthesis as high-quality thin films has been scarcely reported. Here, we demonstrate the synthesis of highly crystalline, coalescent, mixed-phase Co–S thin films using plasma-assisted molecular beam epitaxy (PAMBE). The epitaxial film exhibits substantially improved crystallinity of Co 9 S 8 compared to conventional deposition techniques and reveals the formation of epitaxial, tetragonal CoS 2, which has not been previously observed in this nonmagnetic form. Thus, this work provides crucial diagnostic tools supporting the fabrication of phase-pure, single-crystal Co–S thin films and, with the discovery of the nonmagnetic CoS 2 phase, a new platform for investigating Co–S catalysts in energy and sensing applications.

Source: Crystal Growth & Design

DOI: 10.1021/acs.cgd.5c01203

Authors: Michael Rohde, Gaohang He, Alessandra Canetta, Mohammadali Razeghi, Rikkie Joris, Lino M.C. Pereira, Matthieu Jean Verstraete, Francisco Molina-Lopez, Pascal Gehring, Clement Merckling

Institutions: IMEC, UCLouvain, KU Leuven, University of Liège, Utrecht University, Institute of Theoretical Physics, European Theoretical Spectroscopy Facility

Language: English

Topic: Electrocatalysts for Energy Conversion

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

Open Access status: green

Funders: Université Catholique de Louvain, Fonds De La Recherche Scientifique - FNRS, Fédération Wallonie-Bruxelles, Fonds Wetenschappelijk Onderzoek, KU Leuven, European Research Council, Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture

OpenAlex ID: W7128714656