TiInCrO₆-nanomaterial synthesis, characterization and multi applications

Abstract

In this article, we reported the highly reusable undoped titanium dioxide and doped TiInCrO₆ nanomaterial by simple precipitation method and sonication technique. The prepared nanomaterials were characterized by X-ray diffraction, field-emission scanning electron microscopy with elementary dispersive X-ray, high-resolution transmission electron microscopy, techniques and ultraviolet and visible-diffuse reflectance studies. The influence of operational parameters such as the effect of catalyst loading dye concentration and chemical oxygen demand measurements had also been investigated. The synthesized TiInCrO₆ nanomaterial was proposed as the promising photocatalyst for the degradation of rhodamine B (Rh B) dye and reusability. The mechanism of the photocatalytic effect of the TiInCrO₆ nanomaterial has been discussed. Thus, the use of TiInCrO₆ in water purification showed potential. The photodegradation of Rh B dye was well described by pseudo-first-order kinetics and high quantum yield. The photovoltaic characterization had been studied, cyclic voltammogram measurements. The antibacterial activity of the prepared nanomaterials had been investigated against Gram negative Escherichia coli and Gram positive Staphylococcus aureus bacterial strains.

Introduction

Rhodamine B (Rh B) dye is useful in many industries such as paper, cosmetics, food and textiles. This dye is used to colorize the foodstuffs. The dye and its degradation products such as aromatic amines are greatly carcinogenic and hazardous. Advanced oxidation process is a photocatalysis in waste water treatment technique and it is used for the total mineralization of organics (Alaei et al. 2012; Mills and Lee 2002). Titanium dioxide (TiO₂) is a smart oxide semiconducting material and is greatly studied in the field of environmental water technologies. Remaining nontoxicity, superior redox ability, availability and photodegradation stability of it are also studied (Jiang et al. 2014; Liu et al. 2009; Yang et al. 2008, 2009; Han et al. 2009; Wu et al. 2008). The photocatalytic activity of a multimetal oxide system also depends on their compositions in the current year. The twofold metal oxides such as for TiO₂/Fe₂O₃, TiO₂/SiO₂ TiO₂/MoO₃, TiO₂/WO₃ and TiO₂/ZrO₂ have been generally considered for their single chemical, physical and photocatalytic properties (Ghorai et al. 2011; Do et al. 1994; Papp et al. 1994; Xu et al. 2012; Fu et al. 1996).

Jiang Yin et al. article reported that MCrO₄ (M = Ba and Sr) had shown promising photocatalytic properties (Yin et al. 2003; Tanmay et al. 2013). Surface sensitization by organic dye molecules was reported recently (Zhang et al. 2013; Park et al. 2010; Le et al. 2012 ). In the present work, the preparation of TiO₂ and TiInCrO₆ and their characterization by suitable analytical methods is discussed. It aims to enhance the photocatalytic, of TiO₂ and study of TiInCrO₆ using spray pyrolysis method for photovoltaic application, cyclic voltammeter and bacterial strains (Scheme 1).

Scheme 1

Preparation of TiInCrO₆ nanomaterial

Experimental

Materials

Tetra isopropyl orthotitanate, ammonium dichromate dihydrate, indium chloride, NH₃ solution, nitric acid-65 %, rhodamine B (C₂₈H₃₁ClN₂O₃) are used and is shown in Fig. 1. A gift sample of TiO₂-P25 (80 % anatase) and ethanol, the guaranteed reagents of Sigma Aldrich and deionized water is used as a solvent throughout the experiment.

Fig. 1

Chemical structure of rhodamine B

Synthesis of TiInCrO₆ nanomaterial

TiInCrO₆ nanomaterial was synthesized by the precipitation method. The 1:1 amount of InCl₃ and ((NH₄)₂Cr₂O₇·2H₂O were first dissolved with deionized water. The resulting solution (InCrO₄) was added dropwise into tetra isopropyl orthotitanate solution at room temperature. The above solution was vigorous by stirred for 4 h and than 2–3 drops of conc. nitric acid and 5 mL deionized water were added. The obtained solution was stirred for 2 h and ultra-sonication was done for 20 min, until precipitate was formed. The precipitate was washed with deionized water and ethanol. Then the precipitate was collected and dried in oven at 100 °C for 12 h. The obtained material was finally calcined at 600 °C for 2 h, to achieve InCrO₄ doped-TiO₂ and finally it was calculated as TiInCrO₆ nanomaterial.

Characterization

X-ray diffraction (XRD) spectra were recorded on the X’PERT PRO model X-ray diffractometer from Pan Analytical instruments operated at a voltage of 40 kV and a current of 30 mA with Cu Kα radiation The morphological observation of the prepared materials were made by field-emission scanning electron microscopy (FE-SEM) with elementary dispersive X-ray (EDX) analysis and it was carried out on a FEI Quanta FEG 200 instrument with EDX analyzer facility at 25 °C. The sample was prepared by placing a small quantity of prepared material on a carbon-coated copper grid and allowing the solvent to evaporate by high resolution transmission electron microscopy (HR-TEM), TECNAI G2 FEI F12 model. The crystallinity was characterized by an ultraviolet and visible (UV–vis) DRS and the direct band gap energy was analyzed by UV–visible (Shimadzu UV-1650 PC) spectrophotometer. UV–vis absorbance spectra were measured over a range of 800–200 nm with a Shimadzu UV-1650PC recording spectrometer using a quartz cell with 10 mm of optical path length. The antibacterial activity was studied by disc diffusion method. The test compound was dissolved in DMSO (200 mg/mL) for about half an hour. Commercially available drug disc, ciprofloxacin (10 mg/disc), was used as positive reference standard, and photovoltaic properties of the material were characterized by recording the photo current–voltage curve under illumination of A.M.1.5 (100Mw/cm²) and cyclic voltammetry (CV) measurements were carried out using CHI 60 AC electrochemical analyzer (CHI Instruments Inc., USA).

Results and discussion

XRD analysis

XRD spectra were recorded and peaks at 25.22 and 54.27 are the diffractions from the TiO₂ (101) and (211) crystal planes. Diffractions peaks of anatase phase TiO₂ (JCPDS No. 21-1272) is shown in Fig. 2a. In Fig. 2b highest diffractions peaks at 22°, 27° and 29° are diffraction of the InCrO₄ (100), (200) and (112) crystal planes diffractions peaks of InCrO₄ (JCPDS No. 01-088-0110). The samples of InCrO₄ doped-TiO₂ are present in TiInCrO₆ (Fig. 2c) exhibits a diffraction pattern of FCC crystal structure. The average crystalline size (L) of the TiO₂, InCrO₄ and TiInCrO₆ particles have been calculated from the Debye–Scherrer formula, L = 0.89λ/β cos θ where L is the crystalline size (in nm), l is the wavelength (in nm), b is the full width at half maximum intensity (FWHM-in radian), and u is the Bragg diffraction angle (θ). The average crystalline size of prepared TiO₂ and InCrO₄ material was compared and figured out to be about 80 and 75 nm. The average crystalline sizes of TiInCrO₆ nanomaterial are almost 30 nm. This is consistent with the crystallite size estimated from the XRD analysis.

Fig. 2

XRD analysis a TiO₂, b InCrO₄ and c TiInCrO₆ nanomaterial

Electronic microscopic analysis

FE-SEM analysis

Figure 3a shows the FE-SEM image of TiInCrO₆ nanomaterial. It is shown that there is a modification in the surface morphology spherical-shaped structure. The energy dispersive X-ray analysis shows that the presence of In, Cr, Ti and O in TiInCrO₆ nanomaterial is shown in Fig. 3b. Figure 3a shows the length of the selected particles area using the ‘‘Image J Viewer” software (Loganathan et al. 2015) by surface plot is shown in Fig. 3c.

Fig. 3

Field-emission scanning electron microscopy (FE-SEM). a SEM image, b surface plot selected area highlighted in fig. a, c Energy-dispersive X-ray (EDX) elemental data of TiInCrO₆ nanomaterial

HR-TEM analysis

The synthesized TiInCrO₆ nanomaterial has a well clear spherical-shaped structure in the HR-TEM micrograph. These micrographs in Fig. 4a–c clearly showed the spherical-shaped particles. The selected area electron diffraction (SAED) pattern of the spherical-shaped TiInCrO₆ nanomaterial (Fig. 4d) showed nine diffraction bright rings corresponding to the nine different crystal planes of spherical-shaped structure (with a space of 2.1, 3.5, 5, 5.5, 6.4, 7.5, 8, 8.5 and 9.1 1 nm/1, correspondingly polycrystalline nature). Figure 4e, f represents image profile and particle size distribution (in nm), respectively, of the obtained nanomaterial. The average particle size 103 nm and the selected particles are highlighted in Fig. 4c.

Fig. 4

a–c High-resolution transmission electron microscopy (HR-TEM) images of TiInCrO₆ nanomaterial, d SAED pattern, e surface plot and f particle size selected area highlighted in c, particle size distribution of TiInCrO₆ nanomaterial

UV–vis-DRS analysis

The UV–vis-DRS spectra of undoped TiO₂ and doped TiInCrO₆ are shown in Fig. 5a, b. The direct band gaps of the synthesized nanomaterials have been resolute from the Tauc plots. The plots of [F(R) hv]² vs the photon energy (hv) give the direct band gap of the synthesized TiO₂ and TiInCrO₆ as 3.44 and 3.06 eV, correspondingly. The UV–vis-DRS consequences confirm a decrease in the direct band gap of TiInCrO₆ compare to that of TiO₂. These results expose TiInCrO₆ determination to be functional as an effective photocatalyst.

Fig. 5

UV–vis DRS—direct band gap energy a TiO₂ and b TiInCrO₆ nanomaterial

Preliminary analysis and kinetic study

The initial dye concentration (1 × 10⁻⁴ M) in 50 mL solution of Rh B and the catalyst loading is 0.150 g by UV light irradiation at 365 nm. The TiInCrO₆ material shows superior photocatalytic activity when compare to that of undoped TiO₂ and TiO₂-P25 in, Dark and nil catalyst. Reaction of Rh B undergoes % of degradation from 0, 22.4, 43.9, 61, 80.5 and 89 % in the presence of TiInCrO₆ under UV light at 365 nm in 75 min irradiation is shown in Fig. 6a, b. The stability and reusability of the TiInCrO₆ nanomaterial are achieved investigated by repeating Rh B degradation experiments six more times. After each cycle the TiInCrO₆ photocatalysts were washed thoroughly with water, and a fresh solution of Rh B was made before every run in the photoreactor. The complete degradation occurs in the 1st, 2nd, 3rd, 4th, 5th and 6th cycle. The complete degradation occurs in the 1st cycle (100%), 2nd cycle (98%), 3rd cycle (97%), 4th cycle (96%), 5th cycle (95%) and 6th cycle (95%). The result indicates that the prepared catalysts are stable and reusable. After the completion of the degradation process, the solution is tested for In³⁺ by leaching with Na₂S. There is no precipitation of In³⁺ S (black color) was formed. As there is no further leaching of In³⁺, this material is non-hazardous for wastewater treatment (Balachandran and Swaminathan 2012). In Fig. 6c, the rate is calculated by measuring the time reliant degradation efficiency of Rh B in an aqueous material suspension under UV light irradiation contact. For this reason Rh B itself is a dye which is more active to UV light absorbtion. Its photocatalytic degradation is in the order of the catalyst material TiInCrO₆ > TiO₂. The photodegradation kinetics study of Rh B on TiO₂ and TiInCrO₆ are calculated using the pseudo-first-order kinetics model Eq.  (1)

$$ \ln \left( {C_{0} /C_{t} } \right) = {\text{Kapp}}^{t} , $$

(1)

where Kapp^t is the rate constant (min), C ₀ is the initial concentration of Rh B, and C _t is the concentration of Rh B at reaction time (t) (Zhang et al. 2014; Chandraboss et al. 2015) from the results (Fig. 6d), TiInCrO₆ shows the maximum degradation rate constant, around (1.6361 × 10⁻⁴ s⁻¹) which is higher than that of TiO₂ (1.023 × 10⁻⁴ s⁻¹). The photodegradation rate constants (k′) of Rh B dye in the monochromatic light source yields reaction quantum yield (Subash et al. 2013a, b; Daneshvar et al. 2007; Choy and Chu 2007) by following Eq. (2).

$$ \varPhi = \frac{k}{{2.303I_{0,\lambda } \varepsilon_{D\lambda } l}} $$

(2)

where Φ is the reaction of quantum yield (dimensionless), I _o is the light intensity of the incident light range at 200–800 nm range (1.381 × 10⁻⁶), ε _Dλ is the molar absorptivity of Rh B at 560 nm (3.192 × 10⁴ cm⁻¹ M⁻¹) and (l) is the path length of the reaction tube and is 0.24 m for 50 mL of irradiated solution. The final results of degradation quantum yields by, TiInCrO₆ and TiO₂ are 0.0663 and 0.0414, respectively. These results indicate that the quantum yield of the TiInCrO₆ process is elevated when compare to TiO₂ nanomaterial.

Fig. 6

a Primary analysis, b reusability of TiInCrO₆ on Rh B dye, c kinetic of Rh B dye degradation upon irradiation and b photodegradation efficiency in undoped TiO₂ and doped TiInCrO₆, variations in ln(C ₀/C) as purpose of irradiation time and linear plot of catalysts

Mechanism

Scheme 2 shows the general mechanism of the photodegradation of Rh B dye by modified semiconducting oxide TiInCrO₆ under active UV light source. The energy of incident photons is greater than the band gap energy. The excitation of valence band electrons then promotes the potential reactions. The incident of the photocatalytic surface area with enough energy leads to the arrangement of a positive hole (hv ⁺) into the valence band and an electron (e⁻) through the conduction band. The hole in the valence band reacts with the surface H₂O molecule to generate hydroxyl radicals which reacts with the Rh B dye molecule to degrade the dye.

Scheme 2

Schematic diagram of photodegradation of Rh B on TiInCrO₆ nano material under UV light for successive mineralization

Effect of catalyst loadings and different concentrations

The different catalyst loading of TiInCrO₆ on Rh B has been expected out in the range of 0.100 and 0.150. The total volume of reaction solution is 50 mL, the various amounts of the catalyst loaded in the reaction medium leads to increase the degradation rate. The rate is linearly related to the amount of catalyst loading. Among the three loadings 0.150 g has shown better activity and rapid degradation when compare to other catalyst loading. The effect of different dye concentrations (1 × 10⁻⁴ and 1 × 10⁻⁵) is also investigated under UV light is shown in Fig. 7a. It reveals that the increase in dye concentration leads the activity is decrease. Photodegradation of Rh B more in lesser concentration, when compare to high concentration (Fig. 7b).

Fig. 7

a Effect of catalyst loading and b effect of dye different concentrations

Chemical oxygen demand (COD) analysis

Mineralization of TiInCrO₆ (0.150 g) on Rh B dye (1 × 10⁻⁴) suspension 50 mL pH 7 Solution and air passing with UV light irradiation by COD analysis. The percentage of COD reduction is specified in Fig. 8. After 0, 15, 30, 45, 60 and 75 min irradiation, 0, 25, 46, 59, 82 and 93 % of COD measurements reduction is obtained. This indicates the total mineralization of dye. The mineralization is also specific by formation of calcium carbonate when the evolved gas (CO₂) through degradation is accepted and calcium hydroxide solution is obtained (Subash et al. 2013a, b).

Fig. 8

Chemical oxygen demand (COD) analysis of TiInCrO₆ nanomaterial

Photovoltaic characterization

Figure 9 shows the photo current–voltage (J–V) characteristics of the dye sensitized solar cell (DSSCs). The undoped TiO₂ and InCrO₄ doped-TiO₂ act as photoelectrode are coated on fluorine doped tin oxide (FTO-plate) glass substract. The routine parameter of solar cell is fabricated with TiO₂ and TiInCrO₆ with ruthenium dye (535-bisTBA, N719). From the data, it is clear that (N719) with TiInCrO_6-based cell gives the most brilliant performance with the use of dye as sensitizer reunite the highest value of short-circuit current density, Jsc (4.1 mA/cm²), open-circuit voltage, Voc (500 mV), fill-factor, FF (0.94 and efficiency, η (1.7 %). It is observed that the effectiveness of doped photoelectrode-based cell is much higher than TiO₂ (Liu et al. 2010; Zhang et al. 2011).

Fig. 9

Current density–voltage (J–V) curves for the dye sensitized solar cell (DSSCs) fabricated from TiO₂ and TiInCrO₆ nanomaterial

Antibacterial activity

The bacterial strains viz., (a) Escherichia coli (E. coli) that is a Gram-negative and (b) Staphylococcus aurous (S. aurous) that is a Gram-positive, are used in this investigation (Ariharan and Nagendra Prasad 2014). DMSO is used as control while ciprofloxacin is used as. The TiInCrO₆ nanomaterial is tested against the bacterial strains from the zone of inhibition of the antibacterial activity. The TiInCrO₆ (2) nanomaterial against (a) E. coli, (b) S. aurous shows better activity than TiO₂ (1), is shown in Fig. 10 and Table 1. That TiInCrO₆ nanomaterial has better performance viz photovoltaic properties, photocatalytic activity and antibacterial activity.

Fig. 10

Antibacterial activity (disc diffusion method) a Escherichia coli, b Staphylococcus aurous investigation of TiO₂ and TiInCrO₆ nanomaterial

Table 1 Antibacterial activity (disc diffusion method)

Cyclic voltammogram (CV)

The prepared photocatalyst is a surface occurrence as the photogenerated charge carriers scatter to the surface to begin redox reactions (Sajjad et al. 2013). Prepared nanomaterial TiO₂ and TiInCrO₆ using modified electrode is constructed through the mechanical attachment. Figure 11 shows the cyclic voltammogram of unmodified/modified glassy carbon electrode on the electrochemical oxidation/reduction potential. After the glassy carbon electrode was not made to order within the least prepared photocatalyst, at give is hardly every enrichment or decrement in the cycles. The mashered amid TiO₂ modified glassy carbon electrode, it be investigational that the electrochemical oxidation of KCl is an irreversible process suitable to the peak [anodic current and the (Epa) peak potential of 0.0233 V and i = 1.627 e^−5A]. Although TiInCrO₆ modifies glassy carbon electrode, the deficiency of a well-defined reduction glassy carbon electrode was showing that the electrochemical redox reaction of KCl is a reversible process [enhanced anodic current and the (Epa) peak potential of 0.350 V, and i = 3.334 e^−5A]. These results are (segment = 1 to segment = 40) shown in Fig. 12 indicates that TiInCrO₆ modified glassy carbon electrode has larger adsorption–desorption and high electrochemical reaction than that of TiO₂ nanomaterial. A few literature information has indicated that glassy carbon electrodes modified with metal ion and carbon materials are created to achieve enhanced in comparison to bare GCE (Subash et al. 2013a, b; Zidan et al. 2010; Radhi et al. 2010; Chandraboss et al. 2015). The result thus suggests that the occurrence of could increases current and improves the relation electron transferred by TiInCrO₆ nanomaterial.

Fig. 11

CVs of a uncoated GCE with 0.1 M KCl (violet curve), b TiO₂ coated GCE in 0.1 M KCl (red curve) and c TiInCrO₆ coated GCE in 0.1 M KCl (green curve)

Fig. 12

a TiO₂ coated GCE in 0.1 M KCl (red curves segment 40) and b TiInCrO₆ coated GCE in 0.1 M KCl (blue curves segment 40)

Conclusion

In summary, we had successfully synthesized TiInCrO₆ nanomaterial by simple precipitation method. It was characterized by XRD, FE-SEM with EDX, HR-TEM analysis. FE-SEM and HR-TEM image showed the TiInCrO₆ had spherical-shaped structure. EDX spectra definite this revealed the presence of Ti, In, Cr and O in the catalyst. UV–vis-DRS results demonstrated that the decrease in the direct band gap of TiInCrO₆ nanomaterial compared to undoped TiO₂ nanomaterial. TiInCrO₆ had higher photocatalytic activity and reusability. The influence of operational parameters such as the effect of catalyst loading, dye concentration and COD measurements confirmed complete mineralization of the Rh B molecule. The TiInCrO₆ kinetic study was conducted using the pseudo-first-order kinetic model, and the high quantum yield was calculated. The higher Photovoltaic properties of the DSSCs were characterized. The cyclic voltammogram result shows increased current and improves the relation with electron transferred by TiInCrO₆ nanomaterial. The mechanism of dye degradation is future for the superior photocatalytic activity and water purification performance is shows TiInCrO₆ nanomaterial.