Impact of the stacking fault and surface defects states of colloidal CdSe nanocrystals on the removal of reactive black 5

Abstract

The photodegradation of the reactive black 5 (RB5) with CdSe-MSA nanocrystals (NCs) synthesized by using mercaptosuccinic acid (MSA) was studied. The quantum confinement effect was confirmed via the blue shift of absorbance band and higher energy band gap values. Photoluminescence (PL) emissions were riddled with low energy bands arising from the recombination of trapped charge carriers. The surface stress of the nanocrystals from the ligand capped surface and the atomic position relaxation at the stacking fault interface was linked to an observed hexagonal distortion. The comparison of SO and LO modes was used to analyze the quality of NCs, defect and disorder on the NCs surface. Contact time and RB5 degradation with NCs were investigated to understand the adsorption-photocatalysis synergy. Statistical physics parameters were calculated to explain the dye adsorption on tested nanocrystals. CdSe-MSA showed remarkable UV-light photocatalytic activity with a dye degradation of 89% in 120 min.