Plasma-assisted surface modification of heterogeneous catalysts: principles, characterization, and applications

Abstract

Owing to its abundance of highly reactive species (e.g., radicals, ions, and excited species), plasma technology has been extensively employed for surface modification of heterogeneous materials, playing a pivotal role in industrial chemical production, energy conversion, and environmental remediation. Therefore, a systematic understanding of plasma modification mechanisms, combined with comprehensive characterization and analysis, is of paramount importance. Plasma precisely manipulates the physical structure, chemical properties, and electronic structure of catalysts through two key pathways, including physical processes such as sputtering, etching, and morphology engineering, as well as chemical pathways like radical reactions, functionalization, and doping. In this paper, we discuss the underlying mechanisms responsible for enhanced catalytic performance on plasma-treated catalysts, focusing on plasma's ability to tailor morphology, porosity, surface area, active sites, vacancy concentration, heteroatom doping, band structures and Fermi levels. Then, we introduce the primary characterization techniques typically employed to analyze plasma-assisted modification processes. Notably, plasma-assisted surface modification technology has shown high effectiveness in representative catalytic applications, including oxidation reactions, reduction reactions, catalytic reforming, photocatalysis, and electrocatalysis. Finally, the current challenges and promising future research directions in this field are addressed.