Novel PEI–AuNPs–Mn<sup>III</sup>PPIX nanocomposite with enhanced peroxidase-like catalytic activity in aqueous media

Huifang Xie; Shumei Gu; Jingyi Zhang; Qiong Hu; Xuehua Yu; Jinming Kong

doi:10.1016/j.crci.2017.11.010

Novel PEI–AuNPs–Mn^IIIPPIX nanocomposite with enhanced peroxidase-like catalytic activity in aqueous media

Huifang Xie ¹ ; Shumei Gu ¹ ; Jingyi Zhang ¹ ; Qiong Hu ¹ ; Xuehua Yu ¹ ; Jinming Kong ¹

¹ School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China

Comptes Rendus. Chimie, Volume 21 (2018) no. 2, pp. 104-111.

Résumé

Mn porphyrin provides a possibility to constitute the novel mimic catalyst with peroxidase-like activity. A simple method for preparing a novel catalyst PEI–AuNPs–Mn^IIIPPIX, used in aqueous media, was presented in this paper. The covalent anchoring of Mn^IIIPPIX and PEI were verified, meanwhile gold nanoparticles with the diameter less than 10 nm were dispersed uniformly and stably. The remarkable peroxidase-like catalytic activity of PEI–AuNPs–Mn^IIIPPIX was displayed in the oxidative degradation of azo dye acid orange 7 (AO7) as the model reaction in the presence of trace of H₂O₂. The synergistic effects of PEI–AuNPs and Mn^IIIPPIX on the enhancement of catalytic activity were observed at pH 2.0. Possible pathways involving in the formation of active radicals are proposed. The construction of PEI–AuNPs–Mn^IIIPPIX nanocomposite offers a new insight into the application of Mn porphyrin upon activation of H₂O₂, which have potential applications in many fields.

Métadonnées

Reçu le : 2017-09-04
Accepté le : 2017-11-30
Publié le : 2018-01-17

DOI : 10.1016/j.crci.2017.11.010

Mots clés : Peroxidase-like activity, Mn porphyrin, Gold nanoparticles, Polyethyleneimine, Activation of H₂O₂

Affiliations des auteurs :

Huifang Xie ¹ ; Shumei Gu ¹ ; Jingyi Zhang ¹ ; Qiong Hu ¹ ; Xuehua Yu ¹ ; Jinming Kong ¹

¹ School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China

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     author = {Huifang Xie and Shumei Gu and Jingyi Zhang and Qiong Hu and Xuehua Yu and Jinming Kong},
     title = {Novel {PEI{\textendash}AuNPs{\textendash}Mn\protect\textsuperscript{III}PPIX} nanocomposite with enhanced peroxidase-like catalytic activity in aqueous media},
     journal = {Comptes Rendus. Chimie},
     pages = {104--111},
     publisher = {Elsevier},
     volume = {21},
     number = {2},
     year = {2018},
     doi = {10.1016/j.crci.2017.11.010},
     language = {en},
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Huifang Xie; Shumei Gu; Jingyi Zhang; Qiong Hu; Xuehua Yu; Jinming Kong. Novel PEI–AuNPs–Mn^IIIPPIX nanocomposite with enhanced peroxidase-like catalytic activity in aqueous media. Comptes Rendus. Chimie, Volume 21 (2018) no. 2, pp. 104-111. doi : 10.1016/j.crci.2017.11.010. https://comptes-rendus.academie-sciences.fr/chimie/articles/10.1016/j.crci.2017.11.010/

Version originale du texte intégral

1 Introduction

Synthetic metalloporphyrins are regarded as an ideal platform for catalysis with peroxidase-like activity and draw much interest because of their versatile applications such as epoxidation of alkenes, oxidative degradation of xenobiotics, biosensors, and so on [1–6]. Among the biomimetic metalloporphyrins, iron (Fe) and manganese (Mn) stick out, due to their availability and importance of redox cofactors. In sharp contrast to Fe, analogous Mn porphyrin–catalyzed oxidations remained undeveloped. Mn reconstituting heme proteins such as horseradish peroxidase (Mn^III HRP) [7], microperoxidase-8 (Mn^IIIMP-8) [8], cytochrome c peroxidase (Mn^IIICcP) [9], and myoglobin (Mn^IIIMb) [10] have been prepared, but showed much lower reactivity toward hydrogen peroxide (H₂O₂).

Efforts were made to improve their activities by introducing amino acid residues with imidazole functional groups [11–13]. Similar works have been done for synthetic Mn porphyrins. The additives containing nitrogen such as imidazole and its derivatives [6,14,15] and pyridine derivatives [16] are most applied because of the axial ligand effect due to the formation of hydrogen bond between nitrogen and H₂O₂ coordinated at the Mn center. This effect is generally more pronounced in the reactions catalyzed by Mn^III porphyrins [17]. Other methods reported with higher catalytic activation of H₂O₂ include the choice of Mn porphyrin nanocomposite with the tail of carboxylic groups [6,14], the addition of a carboxylic acid [16], and the immobilization of Mn porphyrin to supports (aminofunctionalized montmorillonite [17], chlorinated graphene oxide [18], modified multiwall carbon nanotube [19], and so on).

Because most synthetic models are designed to function in generally organic homogeneous solution rather than the environmentally benign aqueous media [5], water-soluble mimics come into notice. The biocompatible polymer with imidazole groups and carboxymethylated imidazolium groups was used to support Mn porphyrin in the preparation of the water-soluble mimics [20].

Murakami and Konishi [21] found the remarkable cocatalytic effect of gold nanoclusters on olefin oxidation catalyzed by the Mn porphyrin nanocomposite. Au nanoparticles (AuNPs) have enormous applications due to their unique physicochemical features such as biocompatibility, amphilicity, larger surface carrier capabilities, and gold electronic conductivity [22–24]. However, their tendency of agglomeration needs to be prevented for effective use. To synthesize well-dispersed AuNPs, various nanoreactor systems have been used; among them, polyethyleneimine (PEI) displays the reduction of AuCl₄⁻ to AuNPs under mild conditions and steric stabilization for AuNPs [25–28]. In our previous study, PEI–AuNPs–hemin nanocomposite was proved to have a much-improved peroxidase-like catalysis for decomposing H₂O₂ [28], which indicated that the PEI–AuNPs can enhance the catalytic activity of metalloporphyrins.

In this study, we designed and synthesized a nanocomposite of Mn^III protoporphyrin IX chloride (Mn^IIIPPIX) associated with PEI–AuNPs, which is in a stable colloidal state in water. The oxidative degradation of azo dyes is often used to test the efficiency of peroxidase and its mimic system [29–36]. We herein used PEI–AuNP–Mn^IIIPPIX nanocomposite-catalyzed oxidative degradation of acid orange 7 (AO7), a kind of azo dye, as the model reaction and reported the notable peroxidase-like catalytic ability of this nanocomposite. The possible mechanisms are also proposed.

2 Experimental section

2.1 Materials and apparatus

All the reagents used here were of analytical grade. In particular, branched PEI (average molecular weight, M_w = 25 kDa) was purchased from J&K Scientific Ltd. (Shanghai, China). Hydrogen tetrachloroaurate(III) tetrahydrate (HAuCl₄·4H₂O) was purchased from Sigma–Aldrich (St. Louis, MO) and Mn^IIIPPIX from Frontier Scientific Inc. AO7 (C.I. 15510) was purchased from Beijing Chemical Reagents Co.

UV–vis spectra were recorded using a UV-3600 UV–VIS–NIR spectrophotometer (Shimadzu, Japan). Fourier transform infrared (FTIR) spectrum analysis was performed using an FTIR-8400S spectrophotometer (Shimadzu, Japan). Transmission electron microscopy (TEM) image was obtained using a JEOL JEM-2100 transmission electron microscope at an acceleration voltage of 200 kV.

2.2 Preparation and characterization of PEI–AuNPs–Mn^IIIPPIX

PEI–AuNPs were synthesized as described in our previous report [28]. Then, the PEI–AuNPs were added into a 0.1 mM Mn^IIIPPIX solution (in 0.1 M phosphate-buffered saline [pH 9.0]) in a stoichiometric ratio of 1:0.12. The mixture was stirred at 25°C. After 1 h, the mixture was centrifuged at 14,000 rpm for 60 min, and then the precipitate was washed and centrifuged again in ultrapure water for three times. So prepared PEI-AuNPs-Mn^IIIPPIX was dispersed in water with a final concentration of 0.5 mg/mL and stored at 4°C in the dark for further use.

2.3 Catalytic experiments of PEI–AuNPs–Mn^IIIPPIX

AO7 stocking solution (1000 mg/L) was prepared by dissolving it in 0.1 M phosphate-buffered saline at various pHs between 1.0 and 9.0. The AO7 oxidative degradation was carried out at 25°C in the dark for 120 min as follows: certain amounts of the catalyst were added into the 24 mg/L AO7 solution and the reaction was initiated by adding precalculated amount of H₂O₂. The residual AO7 was quantified by spectrophotometric assay at 484 nm, the maximum peak of AO7. Control reactions in different systems were carried out.

3 Results and discussion

3.1 Preparation and characterization of the catalyst, PEI–AuNPs–Mn^IIIPPIX

Scheme 1 shows the preparation route for PEI–AuNPs–Mn^IIIPPIX. PEI was used as a reducing and protective agent to prepare the PEI–AuNPs by one-step thermal process synthesis [28]. Next, PEI–AuNPs–Mn^IIIPPIX was prepared by an amidation reaction between carboxyl groups of porphyrin and the amino groups of PEI–AuNPs. Thus, Mn^IIIPPIX is heterogenized and protected from forming dimer, which was supposed to be one of the most important deactivation reasons for metal porphyrin [18].

Scheme 1
Preparation route of the PEI–AuNPs–Mn^IIIPPIX nanocomposite.

The prepared catalyst was in a stable colloidal state in water and was characterized using UV–vis spectroscopy and FTIR (Fig. 1).

Fig. 1
(a) UV–vis absorption spectra of PEI–AuNPs, Mn^IIIPPIX, and PEI–AuNPs–Mn^IIIPPIX nanocomposites; (b) FTIR spectrum of the PEI–AuNPs–Mn^IIIPPIX nanocomposite.

The UV–vis spectrum of Mn^IIIPPIX shows three absorption peaks at 370, 464, and 554 nm, respectively. Compared to the spectra of PEI–AuNPs and Mn^IIIPPIX, all three peaks were red shifted, which suggests that the conjugation is formed in the PEI–AuNPs–Mn^IIIPPIX nanocomposite [37,38]. The calculated diameter of AuNPs was 9.6 nm according to Haiss's theory [39]. The FTIR spectrum of the PEI–AuNPs–Mn^IIIPPIX features several characteristic bands. The strong and broad band near 3450 cm⁻¹ belongs to stretching vibration of NH from PEI. There are absorption peaks of stretching vibration of NH₂⁺ at 2948, 2843, and 2300 cm⁻¹. The peak at 1632 cm⁻¹ can mainly be assigned to a CO stretching in carboxyl or amide groups. The peaks at 1469 and 1017 cm⁻¹ are attributed to the NH deformation vibration and CN stretching vibration. The informative spectroscopic data confirmed the covalent anchoring of Mn^IIIPPIX and PEI.

The morphology of PEI–AuNPs–Mn^IIIPPIX was further characterized by TEM, and Fig. 2 presents its representative TEM image and the size distribution.

Fig. 2
(a) TEM image of the PEI–AuNPs–Mn^IIIPPIX nanocomposite. (b) The size distribution histogram of the immobilized AuNPs.

As shown in Fig. 2, the PEI–AuNPs–Mn^IIIPPIX had an approximately spherical morphology and dispersed uniformly with the average diameter of 9.4 nm (200 particles counted), and this matched well with the calculated results mentioned previously.

3.2 Peroxidase-like activities

To examine the catalytic activity of as-prepared PEI–AuNPs–Mn^IIIPPIX, we chose AO7, a typical azo dye as a probe of organic pollutants, which can be degraded by native peroxidase [40,41]. Fig. 3 shows the spectral changes of AO7 in different systems.

Fig. 3
UV–vis spectra of AO7 and its change in different systems.

No obvious change of AO7 spectra is observed when Mn^IIIPPIX is present. The presence of PEI–AuNPs and PEI–AuNPs–Mn^IIIPPIX induced a decrease in the absorbance at 485 nm, which could be due to the adsorption of AO7 on the nanocomposite. It is interesting that there was an obvious decrease when PEI–AuNPs–Mn^IIIPPIX was added, indicating that the combination of Mn^IIIPPIX and PEI–AuNPs played a crucial role. The presence of H₂O₂ enhanced the AO7 degradation catalyzed by Mn^IIIPPIX and PEI–AuNPs–Mn^IIIPPIX and the most thorough degradation of AO7 achieved in the PEI–AuNPs–Mn^IIIPPIX/H₂O₂ system. The results prove the remarkable activity of the novel PEI–AuNPs–Mn^IIIPPIX nanocomposite on the activation of H₂O₂.

3.3 Factors affecting the degradation of AO7 in the PEI–AuNPs–Mn^IIIPPIX/H₂O₂ system

3.3.1 Catalyst dosage

Fig. 4 presents the degradation profile at different catalyst dosages ranging from 0.8 to 4.0 mg/L. As shown in Fig. 4a, the profile of normalized concentrations with time follows an exponential pattern, which may describe the degradation of AO7 according to the pseudo-first-order kinetic reaction:

- \frac{d C_{AO 7}}{d t} = k_{obs} C_{Ao 7}

(1)

ln \frac{C_{AO 7}}{C_{0}} = - k_{obs} t

(2)

where C_AO7 and C₀ represent the concentration of AO7 (mg/L) at time t and the initial time. k_obs is the pseudo-first-order rate constant (min⁻¹) for the degradation of AO7. k_obs were deduced from the linear fitting of ln(C/C₀) versus time.

Fig. 4
(a) Effect of catalyst dosage on the degradation profile of AO7 and (b) the pseudo-first-order rate constant (AO 24 mg/L, pH 2.0, H₂O₂ 1.5 mM).

The k_obs increased significantly as a function of the dosage from 0.8 to 2.4 mg/L (Fig. 4b). Such enhancement in degradation was ascribed to the increased number of active catalytic sites, which are responsible for the formation of active radicals. Further increase in dosage (>3.2 mg/L) does not increase the k_obs obviously, which may be limited by the rate-limiting step of the cleavage of the OO or OH bond in the intermediate where H₂O₂ is coordinated to the catalyst [4].

3.3.2 pH value

pH is another important parameter in the peroxidase-like catalytic reaction. Fig. 5 shows the degradation profile of AO7 and k_obs between pH 1.0 and 9.0 and the maximum k_obs was achieved at pH 2.0. pH value affects the structure of azo dyes, and hydrozone is the main form in the acidic medium with more susceptibility to oxidation [42]. On the other hand, pH plays an important role in the transformation of H₂O₂ coordinated to the metal porphyrin, which is consequently converted to an active intermediate [12,43].

Fig. 5
(a) Effect of pH on the degradation profile of AO7 and (b) the pseudo-first-order reaction rate constant (AO 24 mg/L, PEI–AuNPs–Mn^IIIPPIX 2.4 mg/L, H₂O₂ 1.5 mM).

3.3.3 H₂O₂ concentration

Fig. 6 depicts the degradation profile of AO7 and k_obs at different H₂O₂ concentrations.

Fig. 6
(a) Effect of H₂O₂ concentration on the degradation profile of AO7 and (b) pseudo-first-order rate constant (AO 24 mg/L, PEI–AuNPs–Mn^IIIPPIX 2.4 mg/L, pH 2.0).

As the H₂O₂ concentration increased to 1.5 mM, nearly complete degradation of AO7 was achieved within 120 min. However, the degradation ratio and reaction rate decreased when the H₂O₂ concentration increased to 2.0 mM. Suppose AO7 is completely mineralized according to the reaction:

C₁₆H₁₁N₂O₄S⁻ + 42H₂O₂ → 16CO₂ + 2NO₃⁻ + SO₄²⁻ + 3H⁺ + 46H₂O

the amount of H₂O₂ needed is supposed at least 42-folds of the initial mole concentration of AO7. However, the consumed H₂O₂ in the PEI–AuNPs–Mn^IIIPPIX catalytic process was only 21.4-folds of the initial concentration of AO7, which means that more reactive oxidants play important roles in the degradation of AO7. In a kind of heterogeneous Fenton-like system (GO–Fe₃O₄ nanocomposite/H₂O₂), the initial 35 mg/L AO7 is reported to be oxidative degradation by 220-fold H₂O₂ [44]. In HRP/H₂O₂ system, the 11.32 mg/L AO7 is degraded by 25-fold H₂O₂ [40] and in a Coprinus cinereus peroxidase/H₂O₂ system, the 40 mg/L AO7 is degraded by 34-fold H₂O₂ [41]. So it can be inferred that PEI–AuNPs–Mn^IIIPPIX has high peroxidase-like catalytic activity for H₂O₂ to produce high active oxidant species.

3.4 Possible mechanism

In Mn porphyrin–catalyzed system, the homolysis of OO in Mn peroxide with generation of OH radicals [4,8,10,12,13,45] supposed as to the main pathway (see Scheme 2(A)). In the present study, tert-butyl alcohol (TBA) [46] and methyl alcohol (MeOH) [47] are selected as the scavengers. Fig. 7 proves the obvious role of OH radicals during the degradation of AO7. The degradation ratios decreased from 97% to 33% and 45%, respectively, in the presence of TBA and MeOH and the k_obs decreased 10.2% and 15.0% correspondingly. The results show that degradation of AO7 associated with the generation of OH radicals catalyzed by PEI–AuNPs–Mn^IIIPPIX is one important possible pathway. By comparing the inhibition effects of OH scavengers on the degradation of azo dyes to that in typical OH radicals' driving process [47], it is concluded that degradation of AO7 in the PEI–AuNPs–Mn^IIIPPIX/H₂O₂ system is not merely driven by OH radicals.

Scheme 2
Possible reaction pathways in the activation of H₂O₂ by PEI–AuNPs–Mn^IIIPPIX.

Fig. 7
(a) Effect of scavengers of OH radicals on the degradation profile of AO7 and (b) pseudo-first-order rate constant (AO 24 mg/L, PEI–AuNPs–Mn^IIIPPIX 2.4 mg/L, pH 2.0, H₂O₂ 1.5 mM).

The homolysis of OO with generation of OH radicals was thought to cause the lower reactivity of Mn porphyrin [13]. Many efforts have been made to enhance the activity of Mn^III porphyrin by adjusting the microenvironment of Mn^III in porphyrin [2,13,48–50]. Here, PEI–AuNPs are induced into the system to improve the catalytic activity. Concerning the catalytic system and the results of scavenging OH radicals, we proposed the enhancing mechanisms of Mn^III porphyrin activity in the PEI–AuNPs–Mn^IIIPPIX/H₂O₂ system. The possible reaction pathways for the activation of H₂O₂ by PEI–AuNPs–Mn^IIIPPIX can be described as presented in Scheme 2 (B) and (C).

First, the presence of the carboxyl group in Mn^IIIPPIX affords a suitable tail for the coordination and activation of H₂O₂ due to the formation of an acyperoxy-Mn^III intermediate, in which the heterolytic cleavage of the OO bond is favored by the good leaving of the carboxylate [6,14]. Thus, more active high-valent metal-oxo species are produced, which are responsible for oxygen transfer to the substrate, AO7 (see Scheme 2(B)).

Second, the rich nitrogen atoms in PEI backbone, the nitrogen base, have cocatalytic effects. The similar cocatalytic effects of nitrogen bases have been reported in the catalytic reaction by Mn^III porphyrins [4,15,17,50]. We refer that nitrogen atoms in PET could form the hydrogen bond with H₂O₂, which may facilitate the activation of H₂O₂ as a base to promote the OO bond cleavage, thus favoring the formation of the active catalytic species (see Scheme 2(B)). At the same time, the high density of amino groups in PEI renders the hydrophilic character of the nanocomposite. This hydrolytic stability will enhance the similarity with the natural environment of proteins and may lead to the use of practical heterogeneous catalyst in aqueous media [5].

Among the active species, Mn^IV species is less active and can revert to the active forms by the action of appropriate additives that induce the redox perturbation such as reduction or disproportionation [2,21,48,49], and the gold surface has been reported to have inducibility [21,49]. In PEI–AuNPs–Mn^IIIPPIX/H₂O₂ system, H₂O₂ can be activated through weak Au⋯O interaction with the gold surface. For Mn^IIIPPIX, the linkage between Mn–oxo to the AuNPs surface is formed and the reactivation of Mn^IV species to Mn^V species is facilitated by the linked AuNPs because of the more efficient route for electron transfer at the AuNPs surfaces (see Scheme 2(C)).

In this proposed mechanism, the excess H₂O₂ reacts with the Mn–oxo nanocomposite to produce the molecule of oxygen and water as shown in Scheme 2(D). The excess H₂O₂ also reacts with OH radicals to produce OOH with lower oxidation potential than that of OH:

H₂O₂ + OH → H₂O + OOH

This is why H₂O₂ concentration required is rather low in the PEI–AuNPs–Mn^IIIPPIX/H₂O₂ system, which is proved by the experiments as shown in Fig. 7.

4 Conclusion

In this work, the novel PEI–AuNPs–Mn^IIIPPIX nanocomposite with remarkable peroxidase-like activity in aqueous media was prepared under mild conditions. The nanocomposite showed high hydrolytic stability and the degradation of azo dye AO7 experiments demonstrated that the nanocomposite expresses high peroxidase-like activity in the presence of low concentration of H₂O₂. Our results in this study are one step forward in the development of a new trinary of peroxidase mimics with high activity in water. We proposed the coupling mechanism on the nature of Mn^IIIPPIX, PEI, and AuNPs involving the formation of active radicals: (1) the typical homolysis of OO in Mn peroxide catalyzed by Mn porphyrin with generation of OH radicals; (2) the carboxyl group in Mn^IIIPPIX affords a suitable tail for the coordination and activation of H₂O₂ due to the formation of an acyperoxy-Mn^III intermediate, favoring the heterolytic cleavage of the OO bond; (3) the nitrogen atom in PEI backbone served as a base to promote the OO bond cleavage by forming a hydrogen bond with H₂O₂; and (4) AuNPs facilitate the reactivation of Mn^IV species to Mn^V species because of the more efficient route for electron transfer at the AuNPs surfaces. The construction of the novel catalyst PEI–AuNPs–Mn^IIIPPIX offers a new insight into the application of Mn porphyrin upon activation of H₂O₂, which can induce many further reactions.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (21575066).

Bibliographie

[1] A. Bloodsworth; V.B. O'Donnell; I. Batinić-Haberle; P.H. Chumley; J.B. Hurt; B.J. Day; J.P. Crow; B.A. Freeman Free Radical Biol. Med., 28 (2000), p. 1017

[2] M.L. Merlau; W.J. Grande; S.B.T. Nguyen; J.T. Hupp J. Mol. Catal. A Chem., 156 (2000), p. 79

[3] A. Tovmasyan; H. Sheng; T. Weitner; A. Arulpragasam; M. Lu; D.S. Warner; Z. Vujaskovic; I. Spasojevic; I. Batinichaberle Med. Princ. Pract., 22 (2013), p. 103

[4] B. Meunier Chem. Rev., 92 (1992), p. 1411

[5] B. C Grazia; H. Madeleine; J.E. Warren; D.R. Allan; N.B. Mckeown Science, 327 (2010), p. 1627

[6] S. Banfi; F. Legramandi; F. Montanari; G. Pozzi; S. Quici J. Chem. Soc. Chem. Commun., 18 (1991), p. 1285

[7] K.K. Khan; M.S. Mondal; S. Mitra J. Chem. Soc. Dalton Trans., 6 (1996), p. 1059

[8] J.-L. Primus; S. Grunenwald; P.-L. Hagedoorn; A.-M. Albrecht-Gary; D. Mandon; C. Veeger J. Am. Chem. Soc., 124 (2002), p. 1214

[9] X. Wang; Y. Lu Biochemistry, 38 (1999), p. 9146

[10] M.S. Mondal; S. Mitra Biochim. Biophys. Acta, 1296 (1996), p. 174

[11] A. Gengenbach; S. Syn; X. Wang; Y. Lu Biochemistry, 38 (1999), p. 11425

[12] Y.B. Cai; X.H. Li; J. Jing; J.L. Zhang Metallomics, 5 (2013), p. 828

[13] Y.B. Cai; S.Y. Yao; M. Hu; X. Liu; J.L. Zhang Inorg. Chem. Front., 3 (2016), p. 1236

[14] P.L. Anelli; S. Banfi; F. Legramandi; F. Montanari; G. Pozzi; S. Quici J. Chem. Soc., Perkin Trans., 1 (1993), p. 1345

[15] P. Zucca; G. Mocci; A. Rescigno; E. Sanjust J. Mol. Catal. A Chem., 278 (2007), p. 220

[16] A.C. Serra; C. Docal; A.D.A. Rocha Gonsalves J. Mol. Catal. A Chem., 238 (2005), p. 192

[17] A.L. Faria; T.O.C. Mac Leod; V.P. Barros; M.D. Assis J. Braz. Chem. Soc., 20 (2009), p. 895

[18] A. Zarrinjahan; M. Moghadam; V. Mirkhani; S. Tangestaninejad; I. Mohammadpoor-Baltork J. Iran. Chem. Soc., 13 (2016), p. 1509

[19] S. Rayati; S. Malekmohammadi J. Exp. Nanosci., 11 (2016), p. 872

[20] R. Kubota; S. Asayama; H. Kawakami Chem. Commun., 50 (2014), p. 15909

[21] Y. Murakami; K. Konishi J.Am. Chem. Soc., 129 (2007), p. 14401

[22] R.C. Pawar; S. Kang; S.H. Ahn; C.S. Lee RSC Adv., 5 (2015), p. 24281

[23] H. Tsunoyama; H. Sakurai; N. Ichikuni; Y. Negishi; T. Tsukuda Langmuir, 20 (2004), p. 11293

[24] M. Ovais; A. Raza; S. Naz; N.U. Islam; A.T. Khalil; S. Ali; M.A. Khan; Z.K. Shinwari Appl. Microbiol. Biotechnol., 101 (2017), p. 1

[25] X. Fang; H. Ma; S. Xiao; M. Shen; R. Guo; X. Cao; X. Shi J. Mater. Chem., 21 (2011), p. 4493

[26] J. Han; J. Dai; L. Li; P. Fang; R. Guo Langmuir, 27 (2011), p. 2181

[27] P. Veerakumar; M. Velayudham; K.-L. Lu; S. Rajagopal Appl. Catal. A, 439 (2012), p. 197

[28] J. Kong; X. Yu; W. Hu; Q. Hu; S. Shui; L. Li; X. Han; H. Xie; X. Zhang; T. Wang Analyst, 140 (2015), p. 7792

[29] S.V. Mohan; K.K. Prasad; N.C. Rao; P.N. Sarma Chemosphere, 58 (2005), p. 1097

[30] A.P. Zhang; L. Fang; J.L. Wang; W.P. Liu Environ. Prog. Sustain. Energy, 32 (2013), p. 294

[31] I. Mielgo; C. Lopez; M.T. Moreira; G. Feijoo; J.M. Lema Biotechnol. Prog., 19 (2003), p. 325

[32] P. Ollikka; T. Harjunpää; K. Palmu; P. Mäntsälä; I. Suominen Appl. Biochem. Biotechnol., 75 (1998), p. 307

[33] M. Yan; H. Xie; Q. Zhang; H. Qu; J. Shen; J. Kong J. Mater. Sci. Chem. Eng., 4 (2016), p. 26

[34] V.P. Barros; M.D. Assis J. Braz. Chem. Soc., 24 (2013), p. 830

[35] A. Córdoba; I. Magario; M.L. Ferreira Int. Biodeterior. Biodegrad., 73 (2012), p. 60

[36] S. Pirillo; F.S.G. Einschlag; E.H. Rueda; M.L. Ferreira Ind. Eng. Chem. Res., 49 (2010), p. 6745

[37] J. Chen; L. Zhao; H. Bai; G. Shi J. Electroanal. Chem., 657 (2011), p. 34

[38] C. Shan; H. Yang; D. Han; Q. Zhang; A. Ivaska; L. Niu Biosens. Bioelectron., 25 (2010), p. 1070

[39] W. Haiss; N.T.K. Thanh; J. Aveyard; D.G. Fernig Anal. Chem., 79 (2007), p. 4215

[40] F. Gholamiborujeni; A.H. Mahvi; S. Nasseri; M.A. Faramarzi; R. Nabizadeh; M. Alimohammadi Appl. Biochem. Biotechnol, 165 (2011), p. 1274

[41] V. Yousefi; H.R. Kariminia Int. Biodeterior. Biodegrad., 64 (2010), p. 245

[42] Z. Wu; R. Zhang; Z. Rong Dyest. Color., 51 (2014), p. 1

[43] T.C. Bruice; M.F. Zipplies; W.A. Lee Proc. Natl. Acad. Sci. U.S.A., 83 (1986), p. 4646

[44] N.A. Zubir; C. Yacou; X. Zhang; J.C. Diniz da Costa J. Environ. Chem. Eng., 2 (2014), p. 1881

[45] J.T. Groves J. Inorg. Biochem., 100 (2006), p. 434

[46] Z. Feng; J. Yu; J. Kong; T. Wang Chem. Eng. J., 294 (2016), p. 236

[47] L. Gomathi Devi; S. Girish Kumar; K. Mohan Reddy; C. Munikrishnappa J. Hazard Mater., 164 (2009), p. 459

[48] M.L. Merlau; S.H. Cho; S.S. Sun; S.T. Nguyen; J.T. Hupp Inorg. Chem., 44 (2005), p. 5523

[49] Y. Murakami; K. Konishi New J. Chem., 32 (2008), p. 2134

[50] P. Zucca; C. Vinci; F. Sollai; A. Rescigno; E. Sanjust J. Mol. Catal. A: Chem., 288 (2008), p. 97

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