Dear friend Nowduru Ravikiran

This is a complex question that requires some knowledge of X-ray diffraction (XRD) and graphite structure. I will try to give you a brief overview based on the information I found online.

XRD is a technique that uses X-rays to probe the atomic arrangement of a material. The X-rays are diffracted by the atoms in different directions depending on their spacing and orientation. The resulting diffraction pattern can reveal information about the crystal structure, phase composition, lattice parameters, crystallite size, strain, and preferred orientation of the material.

Graphite is a form of carbon that consists of layers of hexagonal rings of carbon atoms, called graphene sheets. These sheets are stacked on top of each other in an A B A B pattern, where A and B represent two different positions of the carbon atoms relative to each other. The distance between two adjacent graphene sheets is called the interlayer spacing or c-axis spacing, and it is usually denoted by d002. The angle between the c-axis and the normal to the graphene sheet is called the layer orientation angle or gamma angle.

The most prominent peak in the XRD pattern of graphite is the (002) peak, which corresponds to the diffraction from the c-axis spacing. The position of this peak depends on the value of d002, which can vary depending on the type and degree of disorder in the graphite structure. For example, defects such as vacancies, interstitials, impurities, or platelets can affect the interlayer spacing and cause a shift in the (002) peak. The shift can be either to lower angles (left) or higher angles (right), depending on whether d002 increases or decreases.

The intensity of the (002) peak depends on several factors, such as the amount of graphite in the sample, the crystallite size along the c-axis, the degree of preferred orientation of the graphene sheets, and the presence of other phases or structures in the sample. For example, if the graphite sample contains other forms of carbon, such as amorphous carbon or diamond-like carbon, they can reduce the intensity of the (002) peak by scattering or absorbing some of the X-rays. Similarly, if the graphite sample has a low crystallinity or a high degree of disorder along the c-axis, it can result in a broadening and weakening of the (002) peak. Moreover, if the graphite sample has a strong preferred orientation of the graphene sheets parallel to the substrate or perpendicular to the X-ray beam, it can enhance or diminish the intensity of the (002) peak.

Therefore, to interpret your XRD data and support your claim that your sample contains MLG and FLG (multi-layer graphene and few-layer graphene), you need to consider all these factors and compare them with reference data from literature or standards. You also need to analyze other peaks in your XRD pattern besides the (002) peak, such as the (004), (100), (101), and (110) peaks, which can provide additional information about your sample structure and quality.

One possible explanation for your observation of a slight shift to lower angles and significant drop in intensity for your (002) peak could be that your processing method has introduced some defects or disorder in your graphite structure, such as interstitials or platelets between graphene layers. These defects could increase d002 slightly and reduce crystallinity along c-axis, causing a left shift and intensity decrease for your (002) peak. However, this is only a hypothesis, and you need to verify it with more data and analysis.

As for peak fitting, it is not mandatory, but it can help you quantify some parameters such as peak position, intensity, width, area, etc., which can be useful for comparison and calculation purposes. However, you need to be careful about choosing an appropriate model and fitting method for your data.

I hope this helps you understand your XRD results better. If you have any follow-up questions or need more details, please let me know.

Source:

(1) The preparation of synthetic graphite materials with hierarchical pores .... https://pubs.rsc.org/en/content/articlehtml/2019/ra/c9ra00343f.

(2) Influence of temperature and point defects on the X-ray diffraction .... https://www.sciencedirect.com/science/article/pii/S2667056921001012.

(3) When XRD analyzed, what does it mean when a shifted peak ... - ResearchGate. https://www.researchgate.net/post/When-XRD-analyzed-what-does-it-mean-when-a-shifted-peak-is-either-left-hand-or-right-hand.

(4) Ray Diffraction Technique - an overview | ScienceDirect Topics. https://www.sciencedirect.com/topics/engineering/ray-diffraction-technique.

(5) Identification of preferentially exposed crystal facets by X-ray .... https://pubs.rsc.org/en/content/articlehtml/2020/ra/d0ra00769b.

(6) Does peak intensity have any relation to the crystallinty of graphite .... https://www.researchgate.net/post/Does_peak_intensity_have_any_relation_to_the_crystallinty_of_graphite.

(7) Crystal structure of graphite under room-temperature compression and .... https://www.nature.com/articles/srep00520.

The processing has definitely induced severe physical defects in the produced FLG and MLG. The SAED pattern also indicates that. But I'm sure about the absence of any DLC or amorphous carbon in the sample. As you have mentioned I'll try to take closer and carefull look at the other peaks as well. I'm speculating the intensity is reducing as the number of layers in the graphite are getting reduced.

The SAED pattern also indicates that. But I'm sure about the absence of any DLC or amorphous carbon in the sample. As you have mentioned I'll try to take closer and carefull look at the other peaks as well. I'm speculating the intensity is reducing as the number of layers in the graphite are getting reduced

To get a sustainable solution to your problem, please refer to the preprint article given at link DOI: 10.13140/RG.2.2.27720.65287/3 or at link https://www.researchgate.net/publication/352830671.