Liquid-ammonia synthesis of microporous Mg3N2 showing intense red-light emission. Issue 16 (9th April 2018)

• Record Type: Journal Article
• Authors: Rein, Viktor; Wenzel, Olivia; Popescu, Radian; Gerthsen, Dagmar; Feldmann, Claus
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 16(2018)
• Page Start: 4450
• Page End: 4456
• Publication Date: 2018-04-09
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8tc00706c
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Magnesium nitride (Mg3 N2 ) is prepared via lyotropic phases with liquid ammonia (lq-NH3 ). To avoid oxide contamination, the synthesis was performed in the absence of any oxygen source ( e.g., solvents, starting materials and surfactants). Abstract : Magnesium nitride (Mg3 N2 ) is prepared via lyotropic phases with liquid ammonia (lq-NH3 ). To avoid oxide contamination, the synthesis was performed in the absence of any oxygen source ( e.g., solvents, starting materials, and surfactants). Specifically, the lyotropic phase was established by lq-NH3 at −50 °C as the polar phase, heptane as the non-polar dispersant phase, dimethyldioctylammonium iodide (DDAI) as the surfactant, hexylamine as the cosurfactant, and di- n -butylmagnesium as the starting material. Ammonolysis was completed by slow heating to 500–600 °C in a nitrogen atmosphere (N2 ). Structure and purity – especially the absence of oxygen – were studied in detail with different electron microscopic and electron spectroscopic techniques. The as-obtained yellow Mg3 N2 (heated at 500 °C) exhibits high porosity (specific surface area: 176 m 2 g −1 ; total pore volume: 0.41 cm 3 g −1 ; and micropore volume: 0.13 cm 3 g −1 ) and good selectivity regarding CO2 adsorption (CO2 uptake: 108 mg g −1 ; N2 uptake: 9 mg g −1 ; both at 90 bars). After heating to 600 °C, the as-obtained yellow Mg3 N2 (band gap: 2.89 eV) shows intense red emission (600–900 nm) with a quantum yield of 29 ± 3%. Liquid-phase synthesis, oxygen-free Mg3 N2 and intense red emission are reported for the first time, including nanostructured as well as bulk Mg3 N2 .