A DFT Study of the Structure, Electronic, and Photocatalytic Properties of CdX2 (X=Cl, Br, I)

Abstract

In this work, the properties of cadmium halides (CdX₂, X = Cl, Br, I) have been studied with the help of Density Functional Theory (DFT) techniques in structural, electronic and photocatalytic factors. This is aimed to look at how the various halides can alter the electronic properties and photocatalytic behavior of such materials focusing on the possible application of such materials to renewable energy sources. This can be through solar fuel production and environmental challenges. Based on the DFT calculations, it can be seen the halide anion has profound impact on the electronic characteristic of CdX₂ compound in terms of band gaps, electronic charge distribution, and density of state. As far as the compounds investigated are concerned, CdCl₂ has the highest band gap of 4.21 eV and thus it can be used in photocatalysis using UV light but the UV-driven photocatalysts lack applicability. CdI₂ on the other hand, has a smaller band gap (3.07 eV), hence is better in the visible light, making it ideal in the conversion of solar energy. CdBr2 having a band gap of 3.88eV also exhibits mild photocatalytic activity under the UV light to produce additional electron-hole pairs than CdCl₂. These results indicate the significance of slight selection of the halide anion as well as variable adjustment of the band gap to optimize the photocatalytic activity of CdX₂ materials. The lessons learnt can be used in the formulation of next-generation photocatalysts and in the enhancement of materials exhibiting enhanced light absorption, efficacy in charge carrier separation, and more efficient conversion of energy which are essential components of shaping sustainable energy technologies in the future.

Keywords: Cadmium-halide materials (CdX₂), photocatalysis, Density functional theory (DFT), band gap engineering, water splitting, reduction of CO₂.