Evaluation of the Applicability of Modifying CdSe Thin Films by the Addition of Cobalt and Nickel to Enhance the Efficiency of Photocatalytic Decomposition of Organic Dyes

Abstract

This article presents the results of an assessment of the use of CdSe, NiCdSe, and CoCdSe thin films as a basis for photocatalysts used for the decomposition of the organic dyes rhodamine B, cargo red, and indigo carmine. Interest in this area was determined by the need to solve a number of issues related to increasing the efficiency purifying aqueous media from the negative effects of organic dyes, which cannot be disposed of using traditional methods associated with adsorption or filtration. The use of the electrochemical synthesis method to obtain thin films of a given thickness showed that the addition of nickel or cobalt sulfates to the standard electrolyte solution used to obtain CdSe films results in the formation of CdSe films with a higher degree of structural ordering (the crystallinity degree was more than 50%), as well as a decline in the band gap. When analyzing data on the photocatalytic decomposition of organic dyes, it was found that a change in the structure of the films due to the introduction of nickel and cobalt leads, in the case of the decomposition of the rhodamine B dye, to a more efficient decomposition, and in the case of the cargo red and indigo carmine dyes, not only to their complete decomposition and mineralization, but also to a reduction in the time of photocatalytic reactions (decomposition growth rate). Moreover, an analysis of cyclic tests demonstrated that NiCdSe and CoCdSe films maintain 90% of their photocatalytic decomposition efficiency compared to that achieved during the first decomposition cycle, while CdSe degrades after three consecutive cycles and its efficiency reduces by more than 2.5–3 times.

Ultrasonic-Assisted Electrodeposition of Mn-Doped NiCo2O4 for Enhanced Photodegradation of Methyl Red, Hydrogen Production, and Supercapacitor Applications

“…Wan et al [13] performed an investigation on NiCo 2 O 4 catalyst preparation for the degradation of methyl red under visible light irradiation, and they found that the methyl red photodegradation efficiency of mesoporous NiCo 2 O 4 can reach 95.1% under visible light irradiation for 2 h. Additionally, the demonstrated effectiveness of NiCo 2 O 4 in photodegradation within the visible region has enhanced the popularity of this mixed oxide compound, mainly due to its multiple valence states, hypotonicity, ultrastability, and containable structure [12]. To further enhance the properties of NiCo 2 O 4 , one typical method that has gained popularity over recent years is performing transition metal doping onto a semiconductor film [14,15]. Han et al [16] synthesized Cu-doped NiCo 2 O 4 nanosheets using a thermal method for energy storage applications.…”