Qiuhua Yuan

Atomistic simulation of defected magnesium hydroxide as flame retardants

The mechanical properties and the point defect energy of magnesium hydroxide (Mg(OH)2) were studied using the molecular dynamics. Moreover, the microelectronic structure of Mg(OH)2 with point defects in the bulk and on its surface were investigated using the first principles. The simulation results indicate that Mg(OH)2 was easily modified by other cations because of its strong, favorable interstitial and substitution defects via point defect energy calculation. Mg(OH)2 can provide high-efficiency flame retardancy because of the strong OH (OH Schottky defect) or H bond (H Frenkel defect and Schottky defect). The potential model of Mg(OH)2 was established, and molecular dynamics simulation was used to investigate the relations between the crystal structure and the mechanical properties. Mg(OH)2 with special morphology such as nano-sheets was a prior consideration to maintain the composite mechanical properties. The detailed electronic structures of Mg(OH)2 with defects were determined. This work may provide theoretical guidance for choosing dopant element and reveal the element doping mechanism of Mg(OH)2.

Spinel photocatalysts for environmental remediation, hydrogen generation, CO2 reduction and photoelectrochemical water splitting

Over the past few decades, owing to their unique functional properties such as physical, chemical, optical and electronic properties, spinel materials have attracted significant scientific attention in heterogeneous photocatalyst research. Here, we review the main fundamental understanding of the correlations between the performance of spinel structures and their particle shape, size, chemical composition, and photo-Fenton reactions for photocatalytic applications; these include photocatalytic dye degradation for environmental remediation, photocatalytic hydrogen generation, CO2 reduction and photoelectrochemical water splitting. In addition, the key factors and essential strategies to improve their performance and functionality are discussed in detail. Future research pathways and perspectives on the progress of these high performance and cost effective renewable energy materials are provided, along with the improvements in material properties that are necessary to replace current commercial energy materials. It is envisioned that further investigations should focus on surface modification, integrating conductive matrixes and regulating the spinel composition, which will make spinels promising photocatalysts.