(723h) Unfolding Anode-Grade Graphitic Evolution in Iron-Based Catalytic Bio-Graphitization: A Detailed Mechanistic Insight Utilizing in-Situ XRD and PALS
AIChE Annual Meeting
2024
2024 AIChE Annual Meeting
Forest and Plant Bioproducts Division
Catalytic and thermochemical conversion of lignocellulosic materials
Thursday, October 31, 2024 - 5:36pm to 5:54pm
Graphitic carbon materials tailored from biomass are attracting considerable interest as
substitutes for fossil-based anodic resources. However, the complete mechanism of graphitic
evolution from amorphous carbon particles to a highly crystalline graphite architecture in
catalytic graphitization is still obscure. We performed a series of catalytic graphitization
processes with zero-valent iron to understand the catalytic transition and graphitic
progression as a function of temperature. Ambient temperature X-ray analysis and Raman
spectroscopy results of synthesized bio-graphite confirmed incremental changes in
graphitized products at higher thermal index. An exclusive high-temperature In-situ X-ray
diffraction analysis demonstrated that γ-Fe phase transformation influenced the onset of
graphitic reorganization. However, melting iron catalysts controlled the formation of a highly
stable crystalline graphitic structure. An innovative Positron Annihilation Lifetime
Spectroscopy (PALS) Experiment was applied to track the graphitic developments through
atomic repositioning in the matrix. As the graphitization temperature elevated, positron
lifetime showed a decreasing pattern, suggesting fewer and tinier vacancy-type defects and
better graphitic lattice structure. The sample processed at 1500°C exhibited nearly identical
characteristics to commercial graphite. The experimental findings ascertained that, as iron
transitioned into the gamma phase, amorphous carbon gradually dissolved into it and engaged
in interactions, resulting in the formation of a graphitic network that became densely packed
and accumulated in molten iron phase, thus yielding high-quality graphite when precipitated.
This comprehension of the catalytic bio-graphitization mechanism holds promise for crafting
superior-quality anodic materials, thereby facilitating the path to commercialization.
substitutes for fossil-based anodic resources. However, the complete mechanism of graphitic
evolution from amorphous carbon particles to a highly crystalline graphite architecture in
catalytic graphitization is still obscure. We performed a series of catalytic graphitization
processes with zero-valent iron to understand the catalytic transition and graphitic
progression as a function of temperature. Ambient temperature X-ray analysis and Raman
spectroscopy results of synthesized bio-graphite confirmed incremental changes in
graphitized products at higher thermal index. An exclusive high-temperature In-situ X-ray
diffraction analysis demonstrated that γ-Fe phase transformation influenced the onset of
graphitic reorganization. However, melting iron catalysts controlled the formation of a highly
stable crystalline graphitic structure. An innovative Positron Annihilation Lifetime
Spectroscopy (PALS) Experiment was applied to track the graphitic developments through
atomic repositioning in the matrix. As the graphitization temperature elevated, positron
lifetime showed a decreasing pattern, suggesting fewer and tinier vacancy-type defects and
better graphitic lattice structure. The sample processed at 1500°C exhibited nearly identical
characteristics to commercial graphite. The experimental findings ascertained that, as iron
transitioned into the gamma phase, amorphous carbon gradually dissolved into it and engaged
in interactions, resulting in the formation of a graphitic network that became densely packed
and accumulated in molten iron phase, thus yielding high-quality graphite when precipitated.
This comprehension of the catalytic bio-graphitization mechanism holds promise for crafting
superior-quality anodic materials, thereby facilitating the path to commercialization.