Facile synthesis and photocatalytic efficacy of UiO-66/CdIn2S4 nanocomposites with flowerlike 3D-microspheres towards aqueous phase decontamination of triclosan and H2 evolution

https://doi.org/10.1016/j.apcatb.2020.118882Get rights and content

Highlights

  • A novel UiO-66/CdIn2S4 heterostructure material is devised by integrating CdIn2S4 nanosheets with UiO-66 nanoparticles.

  • Hierarchical 3D- microflower structure with high surface area, large interfacial contact and improved optical absorption.

  • A constructive band alignment facilitates easy migration of electrons from CB of CIS to UiO-66.

  • Photoelectrochemical study confirms better channelization of charge carriers and high resistance to recombination.

  • UiO-66/CIS nanocomposites exhibit efficient TCS degradation (0.0094 min−1) and H2 production (2950 μmol g-1 h-1) activity.

Abstract

Construction of porous heterostructure photocatalyst material with improved surface and optoelectrical properties is a practical and effective strategy for mineralization of toxic organic pollutants and water splitting reaction under visible light irradiation. Herein, we have developed a facile hydrothermal route to prepare a series of novel UiO-66/CdIn2S4 heterojunction nanocomposite materials containing finely dispersed UiO-66 spherical nanoparticles (20−40 nm) anchored over high aspect ratio CdIn2S4 nanosheets. Comprehensive characterization of the UiO-66/CdIn2S4 nanocomposites revealed a hierarchical 3D microflower structure with enhanced surface reactive sites, better channelization of charge carriers, high resistance to charge recombination and a favorable band alignment between the two semiconductor components. The optimal photocatalyst (30UiO-66/CdIn2S4) showed improved photocatalytic efficiency towards triclosan degradation with rate constant (0.0094 min−1) twelve times higher than the pure CdIn2S4 (0.0007 min−1). The 30UiO-66/CdIn2S4 photocatalyst also exhibited higher H2 evolution rate (2.95 mmolg−1 h−1) with apparent conversion efficiency of 20.8 %.

Introduction

In the present day, the energy crisis and environmental pollution have emerged as the most pressing global issues which have attracted significant attention from scientific community. In the pursuit of renewable energies for future and sustainable remedial methods for environmental mitigation, the photocatalytic method has been recognized as the most promising technology which can provide long term solution to these global issues [[1], [2], [3]]. The photocatalytic method offers distinct advantages in terms of use of renewable energy, environmental compatibility, economy and high efficacy over conventional methods. The photocatalytic water splitting to generate H2 energy over the surface of a semiconductor is considered as a potential alternative to conventional energy sources [4]. In recent past, metal sulfide based semiconductor materials including CdLa2S4/Ti3C2, Au-Pt/CaIn2S4, MoS2/ZnIn2S4 and AuCu/CaIn2S4 have been extensively evaluated for photocatalytic H2 production [[5], [6], [7], [8]]. Particularly notable are the mixed metal sulfides which possess desirable characteristics such as narrow band gap and negative conduction band potential required for visible light assisted H2 production. CdIn2S4 (CIS) is one of the promising mixed metal sulfide which shows superior thermal and structural stability and significant absorption in visible region in comparison to other mixed-metal sulfide semiconductors [9]. These important physicochemical attributes of CIS has been successfully exploited in many advanced applications including dye sensitized solar cell [10], selective organic transformation [11], photocatalytic water splitting [9] and mineralization of persistent organic pollutants [12]. Due to its narrow band gap (2.0 eV), CdIn2S4 shows high recombination rate of photogenerated charge carriers resulting in low photocatalytic activity. To enhance photocatalytic H2 production activity, coupled semiconductor systems including In2S3/CdIn2S4/In2O3, CdIn2S4/CdWO4 and Pd-CdInS-ZnO have been studied in the past [[13], [14], [15]]. The surface area, grain boundary between semiconductors and morphology are important factors which affect the photocatalytic performance of CIS in a heterostructure system. With an objective to develop novel CdIn2S4 based nano-heterojunction materials for enhanced H2 production, in this work, we have reported the synthesis and photocatalytic application of UiO-66/CdIn2S4 heterostructure nanocomposite materials.

Metal-organic framework (MOF) materials have been used as promising materials towards gas adsorption [16], drug delivery [17], chemical sensing [18], and heterogeneous catalysis [19]. The structural variant of MOFs namely the pillared MOFS have been also evaluated as potential materials for speciation of emerging pharmaceutical contaminants such as ampicillin, amoxicillin, cloxacillin and 2, 4-dichlorophenol from aqueous sources [[20], [21], [22]]. Due to their crystalline nature, tunable porous structure, functional group tolerance and large surface area, MOFs are considered as a promising class of materials for photocatalytic applications. MOF plays a dominant role over traditional semiconductor photocatalyst due to the well-defined combination of metal-oxo cluster with bridged organic linker, which provides a highly crystalline porous structure with large surface area. The metal clusters in MOFs serves as quantum dots for light harvesting, whereas the organic linkers acts as antenna for enhanced absorption of electromagnetic radiation. Recently, MOFs including UiO-66(Zr), MIL-53(Fe), MIL-125(Ti) and HKUST-1 have been demonstrated as excellent photocatalysts with potential applications in H2 evolution, O2 evolution, CO2 reduction and degradation of organic pollutants [[23], [24], [25], [26], [27]]. MOF based heterostructure materials including g-C3N4/NH2-MIL-125 (Ti), MWCNT@MOF-derived In2S3, and NH2-MOF(Al)@Sm2O3−ZnO show efficient photocatalytic activity for water splitting and degradation of antibiotics from aqueous sources [[28], [29], [30], [31]]. Among MOF based photocatalysts, Zr-based MOFs (UiO-66) have aroused great interest due to their exceptional thermal (up to 600 °C) and structural stability in acidic as well as aqueous conditions. However, like many semiconductor materials, UiO-66 exhibits low photocatalytic activity due to low resistance to recombination of photogenerated charge carriers. In order to improve the photocatalytic efficiency of UiO-66, heterojunction systems including UiO-66/g-C3N4, CdS/UiO-66 and In2S3/UiO-66 has been prepared [[32], [33], [34]]. The UiO-66 based heterojunction materials have been studied as photocatalyst for aqueous phase degradation of persistent organic pollutants including tetracycline hydrochloride (TCH), methyl parathion (MP), and Rhodamine B [23,35,36].

The mineralization of endocrine disrupting compounds (EDC) occurring in industrial and agricultural waste water is an important step towards water remediation. Triclosan (TCS) (5-chloro-2-(2,4-dichlorophenoxy)-phenol) is a non-ionic, synthetic, broad-spectrum bacteriostatic antibiotics that is commonly used in personal care and health care products. Triclosan shows long-term persistence in waste water and environment, which causes acute cytotoxicity in many organisms and human beings. By using conventional water treatment methods, removal of TCS can be moderately achieved; however, complete removal of TCS is still challenging. Now a days, advanced techniques, including photocatalysis [37], Fenton oxidation [38], electrocatalysis [39] and electrolysis [40] have been used for degradation of TCS in aqueous media. Taking into consideration the inherent advantages of photocatalytic process, various heterostructre materials such as Au–Cu2O, Bi7O9I3/Bi5O7I, Pd@CuO, and S-Ag/TiO2@g-C3N4 have been studied for degradation of TCS [[41], [42], [43], [44]]. However, most of the existing methods employ low surface area photocatalyst and costly novel metals with moderate efficiency towards TCS removal. In this work, we have described the use of noble metal free UiO-66/CdIn2S4 heterostructure nanocomposite as an efficient photocatalyst for degradation of TCS under visible light irradiation. The CdIn2S4 with hierarchical 3D microspherical structure is obtained by a simple hydrothermal method. The CIS hierarchical microstructure is used as host matrix for fine dispersion of UiO-66 nanoparticles. The as synthesized composite system exhibited high surface area, improved charge mobility, high resistance to charge recombination and enhanced photocatalytic activity.

Section snippets

Synthesis of UiO-66/CdIn2S4 nanocomposite materials ((X)UiO-66/CIS)

Pure UiO-66 and CIS material were synthesized using a simple solvothermal method. The detailed experimental procedure is described in the supporting information file. The UiO-66/CIS nanocomposite materials were synthesized by an in-situ impregnation technique (Scheme 1). In a typical experiment, required amount of UiO-66 was dispersed in 30 ml of water containing cadmium chloride (1 mmol) and indium chloride (2 mmol) and stirred for 30 min. To this suspension, thiourea aqueous solution (4 mmol

Characterizations of photocatalytic materials

The XRD patterns of (X)UiO-66/CIS nanocomposite materials together with pure CIS and UiO-66 are presented in Fig. 1. Pure CIS shows a series of well-defined and intense diffraction peaks with d values of 6.23, 3.86, 3.30, 2.71, 2.10 and 1.93 Ǻ which are characteristics to the cubic crystal lattice with a spinel structure (JCPDS No. 27-0060). No other analogous or impurity phases including CdS and In2S3 could be noticed which suggests high phase purity of the spinel CdIn2S4 material (Fig. 1

Conclusion

In summary, we have synthesized a novel UiO-66/CIS heterojunction nanocomposite with hierarchical 3D micro-spherical structure through a facile hydrothermal technique for efficient TCS degradation and H2 evolution under visible light irradiation. The hierarchical materials exhibit unique structural, compositional as well as opto-electrical properties, which include high crystallinity, surface exposed reactive site, nanosized interfacial contact, strong absorption in visible region, rapid

Credit author statement

Ranjit Bariki: Photocatalytic material synthesis and photocatalytic application study, manuscript writing, Conceptualization, Methodology

Dibyananda Majhi: Characterization study using XRD, Raman and interpretation of data Krishnendu Das: Characterization using XPS, BET and interpretation

Arjun Behera: Data curation and interpretation

B.G. Mishra: Supervision, Conceptualization, Methodology, Funding acquisition, writing-reviewing

Declaration of Competing Interest

None.

Acknowledgement

The financial support from Council of Scientific and Industrial Research (CSIR), New Delhi (Grant 01(2947)/18/EMR-II) is gratefully acknowledged.

References (64)

  • Y.P. Bhoi et al.

    Catal. Commun.

    (2018)
  • D. Majhi et al.

    Appl. Catal. B: Environ.

    (2020)
  • L. Cheng et al.

    Appl. Catal. B: Environ.

    (2020)
  • J. Ding et al.

    Appl. Catal. B: Environ.

    (2018)
  • Y. Liu et al.

    J. Nanopart. Res.

    (2018)
  • R. Sasikala et al.

    Appl. Catal. A Gen.

    (2013)
  • R. Abazari et al.

    J. Hazard. Mater.

    (2019)
  • R. Abazari et al.

    Ultrason. Sonochem.

    (2018)
  • R. Abazari et al.

    Ultrason. Sonochem.

    (2018)
  • L. He et al.

    J. Hazard. Mater.

    (2019)
  • G. Zhou et al.

    Appl. Catal. B: Environ.

    (2018)
  • R. Abazari et al.

    J. Hazard. Mater.

    (2019)
  • Y. Pi et al.

    Appl. Catal. B: Environ.

    (2019)
  • W. Dong et al.

    J. Colloid Interface Sci.

    (2019)
  • J. Mehta et al.

    Environ. Res.

    (2019)
  • J. Abdi et al.

    J. Environ. Chem. Eng.

    (2019)
  • H. Wang et al.

    Appl. Catal. B: Environ.

    (2015)
  • C. Chang et al.

    Appl. Catal. B: Environ.

    (2019)
  • J. Ren et al.

    Int. J. hydrogen energ.

    (2014)
  • B. Liu et al.

    Appl. Catal. B: Environ.

    (2018)
  • W.K. Unger et al.

    Solid State Commun.

    (1978)
  • Z. Yang et al.

    Chemosphere

    (2019)
  • Q. Liang et al.

    J. Colloid Interface Sci.

    (2018)
  • J. Wang et al.

    Sci. Total Environ.

    (2019)
  • B. Baral et al.

    J. Colloid Interf. Sci.

    (2019)
  • J. Luo et al.

    ACS Nano

    (2019)
  • A. Behera et al.

    J. Phys. Chem. C

    (2019)
  • J. Ding et al.

    J. Mater. Chem. A Mater. Energy Sustain.

    (2016)
  • G. Swain et al.

    Inorg. Chem.

    (2019)
  • J. Chen et al.

    Beilstein J. Nanotechnol.

    (2019)
  • N. Qin et al.

    Langmuir

    (2015)
  • M.M. Kamazani et al.

    RSC Adv.

    (2016)
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