Effects of Physical and Chemical States of Iron-Based Catalysts on Formation of Carbon-Encapsulated Iron Nanoparticles from Kraft Lignin

• Main Authors: Xuefeng Zhang, Qiangu Yan, Jinghao Li, Jilei Zhang, Zhiyong Cai
• Format: Article
• Language: English
• Published: MDPI AG 2018-01-01
• Series: Materials
• Subjects: kraft lignin; biopolymer; iron nanoparticles; iron nitrate; thermal treatment; carbon-encapsulated iron nanoparticles
• Online Access: http://www.mdpi.com/1996-1944/11/1/139

Effects of physical and chemical states of iron-based catalysts on the formation of carbon-encapsulated iron nanoparticles (CEINs) synthesized thermally from kraft lignin were investigated. Experimental results indicated that if solution-based iron nitrate (FeN) was used as an iron source for the catalyst, CEINs observed were α-Fe and γ-Fe-based cores encapsulated by few layers graphitic-carbon (mostly 1–5 layers) and the majority of these CEINs were embedded in amorphous carbon matrix. The formation of graphitic-carbon shells is believed based on the dissolution and precipitation mechanism of amorphous carbon acting as the carbon source. If solid-based iron nanoparticles (FePs) were used as the catalyst, CEINs observed were α-Fe, γ-Fe, and Fe3C-based cores encapsulated with tangled graphitic-carbon nanoribbons and carbon tubules and the majority of these CEINs were found along the edge of amorphous carbon matrix. The growth of tangled graphitic-carbon nanoribbons and carbon tubules is based on a chemical vapor decomposition process, i.e., the carbonaceous gases from kraft lignin decomposition served as the carbon source.