Mapping the scalability, effect of reaction atmosphere, and catalyst dose in bamboo-like CNT synthesis for efficient electrocatalysis

Carbon nanotubes (CNTs) play vital role in electrocatalysis due to large surface area and unique one-dimensional conductivity, reducing electron scattering. The abundance of the defect sites in CNTs, the catalytically active sites vary based on synthesis methodology. While chemical vapor deposition (CVD) technique has been widely studied, a detailed correlation of the synthetic parameters in the floating catalyst method, with activity is missing. Scalability is also crucial to study as in CVD technique carbon vapor is injected into the furnace but floating catalyst method relies on in-situ vapor generation from solid carbon precursors. We have mapped catalyst dosage and reaction atmosphere's impact on electrocatalytic efficiency for various CNTs produced under different conditions towards the oxygen reduction reaction (ORR) and rationalised the variation in activity by spectroscopic evidences. Optimized CNTs exhibit a high electrocatalytic ORR efficiency with prolonged durability, highlighting the role of the interaction between CNTs and encapsulated iron nanoparticles in response to reaction atmosphere.