Physicochemical characterization of candle soot functionalized with nitric acid

Abstract

Carbon nanoparticles (CNPs) have been identified as critical components in a variety of applications such as sensors, quantum dots, electrocatalysts, energy storage, and functional coatings. Candle soot can be used to produce uniform and efficient CNP materials. However, the known shortcomings, such as surface functionality and chemical stability have hindered the candle soot from being using as electrocatalysts. In this work, the synthesized of nitric acid functionalized candle soot (f-CS) will be compared with bare candle soot (CS) and wash candle soot (w-CS) in terms of physicochemical properties which to be used in electrochemical reaction. The nitric acid treatment was introduced into the candle soot surface to introduced oxygenated functionalities group and impeding the agglomeration and/or loss of active surface. The samples were evaluated using X-ray diffraction (XRD), Brunauer–Emmet–Teller (BET), field emission scanning electron microscopy (FESEM), and Raman analysis. After nitric acid treatment, the BET surface area has slightly reduced from 111.01 m2/g to 95.66 m2/g. These results demonstrated that oxygenated groups are incorporated into the carbon pore structure, blocking up the carbon pores. Experiments utilizing Raman demonstrated that functionalized candle soot has higher ID/IG ratio with value of 0.90 than bare soot with value of 0.82. Increased surface defects will give additional sites to anchor of metal particles, thereby increasing the number of metal-active sites. This f-CS will serve as a feasible basis material for an electrocatalysts, anode materials for energy storage, etc.