Roles of CeO2 in preparing Ce-doped CdIn2S4 with boosted photocatalytic degradation performance for methyl orange and tetracycline hydrochloride

Enhanced carrier separation and decreased reaction barrier in cobalt-doped CdIn2S4 nanosheets for photocatalytic hydrogen evolution

Doping with 3d transition metal atoms is a widely used strategy to enhance the photocatalytic activity of metal sulfides, although the introduction of d-electrons often leads to the formation of deep localized states that function as recombination centers, thereby reducing charge separation efficiency. In this study, cobalt (Co) dopants were introduced into CdIn2S4 (CIS) nanosheets, and a combination of extensive characterization techniques and first-principles calculations was utilized to investigate their role in enhancing the photocatalytic hydrogen evolution reaction (HER). In the bulk structure of CIS, Co doping not only reduces the bandgap, improving visible light absorption without introducing deep localized levels but also increases the difference between the effective masses of electrons and holes, thus promoting carrier separation. At the surface, the electron-donating ability of Co is lower than that of the replaced In atoms, leading to modifications in the electronic properties of neighboring atoms. This results in optimized hydrogen adsorption free energy and enhanced HER kinetics. Consequently, the 3at%Co-CIS sample exhibits an optimal H2 evolution rate of 0.83 mmol·g-1·h-1 under visible light, which is 3.95 times higher than that of pristine CIS. This work not only improves the photocatalytic performance of 2D CIS but also provides valuable insights into the role of transition metal doping in photocatalysts.

CdIn2Se4@chitosan heterojunction nanocomposite with ultrahigh photocatalytic activity under sunlight driven photodegradation of organic pollutants

This research focused on synthesizing a CdIn2Se4@Ch nanocomposite by doping CdIn2Se4 into chitosan using a photolysis assisted ultrasonic process. The aim was to enhance the photodegradation efficiency of ofloxacin and 2,4-dichlorophenoxyacetic acid under sunlight. The synthesized CdIn2Se4@Ch nanocomposite was investigated via different techniques, including XRD, XPS, FTIR, TEM, DSC, TGA, UV-Vis and PL. The study also investigated the influence of various reaction parameters, including the effects of inorganic and organic ions. The synthesized nanocomposite demonstrated exceptional efficiency, achieving 86 % and 95 % removal rates, with corresponding rate constants of 0.025 and 0.047 min-1. This performance surpasses that of CdIn2Se4 by approximately 1.35 and 2.25 times, respectively. The values of COD were decreased to 78 and 86 % for ofloxacin and 2,4-dichlorophenoxyacetic, while the TOC values decreased to 71 and 84 %, respectively, from their premier values. The improvement in performance is associated with the introduction of CdIn2Se4 into chitosan, resulting in the self-integration of Cd into the catalyst. This creates a localized accumulation point for electrons, enhancing the efficiency of charge separation and further reducing the surface charge of chitosan. Experimental evidence suggests that superoxide and hydroxyl radicals play a significant role in the photodegradation of pollutants. Additionally, the nanocomposite exhibits excellent stability and can be reused up to five times, indicating remarkable stability and reusability of the developed photocatalyst.