Structural Properties and ELNES of Polycrystalline and Nanoporous Mg3N2. (February 2020)

• Record Type: Journal Article
• Authors: Wenzel, Olivia; Rein, Viktor; Popescu, Radian; Feldmann, Claus; Gerthsen, Dagmar
• Is Part Of: Microscopy and microanalysis. Volume 26:Number 1(2020)
• Page Start: 102
• Page End: 111
• Publication Date: 2020-02
• Subjects: crystal size effects, -- electron energy-loss spectroscopy, -- magnesium nitride, -- surface effects; Microscopy -- Periodicals; Microchemistry -- Periodicals; 502.82
• DOI: 10.1017/S1431927619015307
• Languages: English
• ISSNs: 1431-9276

Abstract

Abstract: Nanoporous, high-purity magnesium nitride (Mg3 N2 ) was synthesized with a liquid ammonia-based process, for potential applications in optoelectronics, gas separation and catalysis, since these applications require high material purity and crystallinity, which has seldom been demonstrated in the past. One way to evaluate the degree of crystalline near-range order and atomic environment is electron energy-loss spectroscopy (EELS) in a transmission electron microscope. However, there are hardly any data on Mg3 N2, which makes identification of electron energy-loss near-edge structure (ELNES) features difficult. Therefore, we have studied nanoporous Mg3 N2 with EELS in detail in comparison to EELS spectra of bulk Mg3 N2, which was analyzed as a reference material. The N-K and Mg-K edges of both materials are similar. Despite having the same crystal structure, however, there are differences in fine-structural features, such as shifts and absences of peaks in the N-K and Mg-K edges of nanoporous Mg3 N2 . These differences in ELNES are attributed to coordination changes in nanoporous Mg3 N2 caused by the significantly smaller crystallite size of 2–6 nm compared to the larger (25–125 nm) crystal size in a bulk material.