Hierarchical nanostructures of CdIn2S4via hydrothermal and microwave methods: efficient solar-light-driven photocatalysts

Abstract

We have demonstrated the synthesis of nanostructured CdIn 2 S 4 with a fascinating 'marigold flower' morphology using a hydrothermal method, and mixed morphologies (flowers, spheres and pyramids) using a microwave method. In the microwave synthesis, the product was formed within 15 min, whereas by the hydrothermal method more than 24 h was required. In the microwave method, various capping agents were used that result in different particle morphologies. Hydrothermal formation of crystalline CdIn 2 S 4 nanotubes in methanol showed a significant effect of reaction medium on morphology. Synthesis of these crystalline CdIn 2 S 4 nanopyramids and 'marigold flowers' has also been demonstrated using microwave synthesis for the first time. An XRD study showed a cubic spinel structure for CdIn 2 S 4 prepared by both methods. The band gap for CdIn 2 S 4 was 2.27 eV when synthesized using the microwave method, and 2.23 eV using the hydrothermal method, implying that the microwave method produces a lower particle size than the hydrothermal method. A noteworthy aspect of this work is that we obtained novel ternary chalcogenide hierarchical nanostructures by simple hydrothermal and microwave methods. Considering that the band gap of the hierarchical CdIn 2 S 4 is within the visible region, we compared its ability to photocatalytically degrade methylene blue (MB) with that of CdS. The marigold flowers, nanoparticle spheres and nanopyramids of CdIn 2 S 4 synthesised by microwave method gave almost 30% enhancement in the degradation of MB as compared to CdS under direct sunlight. This is of importance, considering that CdIn 2 S 4 has potential for applications in solar energy conversion and opto-electronic devices.

Nanostructured materials for photocatalysis

“…Due to their excellent optoelectronic and catalytic properties, they have been successfully implemented in solar cells, light emitting diodes, radiation detection devices and photocatalysis. [127][128][129][130][131][132][133][134][135][136][137] Among these highly functional chalcogenides, SCs of the group I-III-VI (silver-indiumsulfide (AgInS2), copper-gallium-sulfide (CuGaS2) and copper-indium-sulfide (CuInS2)) and group II-III-VI (cadmiumindium-sulfide (CdIn2S4) and zinc-indium-sulfide (ZnIn2S4)) have been studied in photocatalysis. Within these two groups, group I-III-VI semiconductors: AgInS2, CuGaS2 and CuInS2 are highly preferred due to their negligible toxicity, high photoconductivity, high stability, environmental benign composition and visible light activity for many novel reactions.…”

Facile preparation and visible light photocatalytic activity of CdIn2S4 monodispersed spherical particles

“…selecting visible light photocatalysts [22][23][24][25]. It can be reasonably expected that ternary chalcogenide compounds might be widely applied to photocatalysis in future.…”

Surfactant-free hydrothermal synthesis of flower-like Bi 2 WO 6 with enhanced solar-light-induced photocatalytic performance

“…However, TiO 2 can only be activated by UV light (only occupying around 4% of solar energy) because of its large bandgap of 3.2 eV, which limits its practical applications [5]. Therefore it is necessary to develop efficient photocatalysts that are responsive to solar light, and the research in this field has attracted more and more attention [6][7][8].…”

“…However, TiO 2 can only be activated by UV light (only occupying around 4% of solar energy) because of its large bandgap of 3.2 eV, which limits its practical applications [5]. Therefore it is necessary to develop efficient photocatalysts that are responsive to solar light, and the research in this field has attracted more and more attention [6][7][8].Recently, Bi-based photocatalytic materials have drawn much attention because of the unique electron structure of Bi, which is beneficial for promoting the mobility of photo-generated carriers, such as Bi 2 WO 6 [9], BiVO 4 [10], Bi 2 MoO 6 [11] and BiOX [12]. Bi 2 WO 6 is the simplest member of the Aurivillius family with a structure consisting of a perovskite layer (WO 4 ) 22 which lies between the (Bi 2 O 2 ) 2+ layers [13].…”