SAXS investigation of nanoporous structure of thermal-modified carbon materials

Bogdan K Ostafiychuk,Nadiia I Nagirna,Yuriy O Kulyk,Volodymyr I Mandzyuk

doi:10.1186/1556-276x-9-160

Bogdan K Ostafiychuk, Nadiia I Nagirna + Show 2 more

Open Access

https://doi.org/10.1186/1556-276x-9-160

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Abstract

The article investigates the effect of thermal modification of porous carbon material (PCM), obtained from plant feedstock, on its morphology and fractal structure by small-angle X-ray scattering (SAXS) method. The analysis of the scattering intensity curves serve the basis for calculating the parameters of the PCM porous structure: the Porod constant, the Porod invariant, average pore radius, specific surface area, and mass and surface fractal dimensions. It has been found out that the PCMs obtained have fractal structure, formed from mass and surface fractals, the sizes of which increase at the growth of temperature and modification time.PACS81.05.Uw; 61.05.cf; 82.47.Aa

Highlights

One of the principal ways to improve the existing and create new electrochemical technologies is the development of new electrode materials, possessing necessary properties: high electrocatalytic activity, stability, and abundance of original components [1]. These requirements can be provided by creating electrodes on the porous carbon material (PCM) bases that are actively used as electrode materials for primary and secondary chemical power sources and supercapacitors [2,3,4,5,6,7]
The results of the calculations conducted for PCM, modified at 300°С, show the non-monotonous changes in parameters of the porous structure (Table 1)
The samples contain the generated small-scale volumetric fractal structure, formed by carbon nanoclusters, the size of which can be calculated by the formula L1 ≈ 2 π / s2, where s2 is the lower limit of the fractal mode on the scale s

Summary

Introduction

One of the principal ways to improve the existing and create new electrochemical technologies is the development of new electrode materials, possessing necessary properties: high electrocatalytic activity, stability, and abundance of original components [1]. To study changes caused by such modifications a wide range of methods are currently used: X-ray diffraction method [13], small-angle X-ray scattering (SAXS) [14,15,16], small-angle neutron scattering [16,17,18], gas adsorption/desorption [19,20,21], scanning tunnel microscopy [22], atomic force microscopy [23], and transmission electron microscopy [24] Each of these methods has its advantages and disadvantages, but they provide a possibility to obtain important information about the porous structure of the materials (specific area, total pore volume, micropore volume, dimensions and forms of pores, their size distribution, fractal structure, etc.). The aim of the work is to perform thermal modification of PCM at different temperatures and times and to investigate the effect of this modification on its morphology and fractal structure using the SAXS method

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