Simulating Powder X-ray Diffraction Patterns of Two-Dimensional Materials

Abstract

Powder X-ray diffraction (PXRD) is widely used to study atomic arrangements in ordered materials. The Bragg equation, which describes diffraction of a three-dimensional crystal, fails in two-dimensional (2D) cases. Complete integration of diffraction signals from a continuum instead of discrete directions in the Bragg equation is thus required for proper data interpretation of 2D materials. Furthermore, modeling of preferred orientation of the 2D crystals as well as geometric disorders are also of vital importance. Here, we present a complete integration method in real space (CIREALS) for PXRD simulation of monolayer or multilayer 2D crystals, especially 2D metal–organic layers and 2D covalent organic frameworks. By working in real space instead of reciprocal space, we can readily capture the 2D geometry and preferred orientation of these materials. The predicted PXRD patterns by CIREALS facilitates structure analysis of these new types of 2D material.

Ultrathin water-stable metal-organic framework membranes for ion separation

“…Compared with Al-MOF bulks, XRD peaks of Al-MOF nanosheets are weak, and a few peaks even disappear ( fig. S4), largely owing to the loss of diffraction signals in the out-of-plane direction and the nonplanar shape of the nanosheets (24). X-ray photoelectron spectroscopy (XPS), energy-dispersive spectroscopy (EDS), ultraviolet-visible spectra (UV-Vis), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and thermogravimetric analysis (TGA) characterizations in figs.…”

Recyclable Printed Circuit Boards and Alkali Reduction Wastewater: Approach to a Sustainable Copper-Based Metal–Organic Framework

“…However, a few peaks of CuBDC-W became weak and even disappeared, such as (201̅), (310), (221), and (112) facets. This is largely due to the loss of diffraction signals in the out-of-plane direction and the nonplanar shape of CuBDC-W with thinner stacked lamellae. , Furthermore, a more straightforward SAED pattern further demonstrated the retained crystallinity of CuBDC-W (Figure S3). Collectively, this observation demonstrates that CuBDC-W owns an identical crystalline structure to CuBDC, reflecting the successful preparation CuBDC MOF crystals derived from PCB and AR wastewater.…”

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