Rapid hydrothermal synthesis of highly crystalline transition metal (Mn & Fe) doped CuSe nanostructures: Applications in wastewater treatment and room temperature gas sensing

Abstract

In this paper, we report on the rapid hydrothermal synthesis of CuSe 2D nanocrystals. The nanostructures were synthesized for very short reaction durations of 3 h. The influence of two different transition metal inclusions (Mn & Fe) on the growth and properties of CuSe nanocrystals was investigated. Transition metal dopants were found to have a prominent influence on the morphological, magnetic, optical and photocatalytic behavior of the material. Structural properties show that the nanostructures have a single phase with the hexagonal structure. The inclusion of the transition metal dopants (Mn and Fe) had no influence on the phase of the nanostructures although growth along certain crystal directions was restricted. Morphologies like flakes and hexagonal discs were obtained, all in the nanoscale dimensions. Doping resulted in the development of catalytically active edge sites which are more prominent in the case of Fe doping. Magnetic studies reveal conversion of diamagnetic CuSe into paramagnetic material upon doping with Fe and Mn. The gas sensing property of the synthesized nanostructures was tested against NO2 gas. The hexagonal nano-discs showed the highest sensitivity reaching 25% at 40 ppm NO2 concentration. The nanostructures were utilized for the photodegradation of methylene blue (MB) dye under UV-Visible light illumination. Addition of the transition metal dopants resulted in the enhancement of photocatalytic activity of the material, improving the degradation percentage from 59.4% to 64.5%.