Phase Tuned Originated Dual Properties of Cobalt Sulfide Nanostructures as Photocatalyst and Adsorbent for Removal of Dye Pollutants

Abstract

Synthesis of cobalt sulfide nanostructures (NS) with tunable phases was achieved by changing the reaction temperature through facile precipitation method. Prepared NS were fully characterized by powder Xray diffraction, UV−vis spectroscopy, diffuse reflectance spectroscopy, Xray photoelectron spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, energydispersive X-ray spectroscopy, selected area electron diffraction, thermogravimetric analysis, and Brunauer−Emmett−Teller analysis. The NS synthesized at 90 °C (CoS) have photocatalytic property, while at 70 °C (Co 4 S 3 ) they were found to have adsorption activity. This change of property with the tuning of the phases of cobalt sulfide was observed for the first time to our knowledge. On the one hand, organic dyes such as rhodamine B (RhB), methylene blue (MB), crystal violet, and nile blue were subjected to photocatalysis under visible light irradiation at pH 6.8 and were found to degrade organic dyes rapidly and efficiently with only 2% loss of activity after the seventh cycle of reaction. On the other hand, the adsorbent has shown extremely high adsorption efficiency with maximum adsorption capacity for Congo red (3270 mg/g), RhB (1138 mg/g), and MB (629 mg/g). The adsorption process followed the pseudo-second-order rate kinetics and Langmuir adsorption isotherm model. The reusability of adsorbent was found up to eighth cycle without significant loss of activity.

Amine-Functionalized and Hydroxyl-Functionalized Magnesium Ferrite Nanoparticles for Congo Red Adsorption

“…The Langmuir isotherm model is based on homogeneous systems and the monolayer of adsorbate molecules onto the adsorbent surface. 55,70 The linear form of the Langmuir equation is given as eq 6:…”

Regulating Li+ migration and Li2S deposition by metal-organic framework-derived Co4S3-embedded carbon nanoarrays for durable lithium-sulfur batteries

“…2f) shows that the doublets at 163.8 and 162.6 eV can be indexed to S 2p 1/2 and S 2p 3/2 of Co 4 S 3 . In addition, the peaks located at 169.3 and 170.5 eV can be identified as the oxidized sulfur species [29].…”

Smart Bifunctional Sb2Se3 Nanorods for Integrated Water Purification: Insoluble Liquid Separation and Photoelectrochemical Degradation

“…The reduction reactions that produce oxygen radicals (e − +O 2 →O 2 .− ) under light illumination were readily observed at the Sb 2 Se 3 /electrolyte (orange water) interface, generating a relevant cathodic photocurrent spontaneously followed by the reactions shown in the inset of Figure a. To verify the influence of the formation of an oxygen radical, the photodegradation was performed in the oxygen‐removed electrolyte solution under high‐purity N 2 conditions, resulting in reduced photocurrent generation (Figure S3 in the Supporting Information) . The photodegradation performance was subsequently evaluated by chronoamperometry measurements using a three‐electrode system, and a cathodic photocurrent density of 1 mA cm −2 at −0.4 V (0.1 V vs. RHE) was obtained, as shown in Figure b.…”