Synthesis of glucose-mediated Ag–γ-Fe<sub>2</sub>O<sub>3</sub>multifunctional nanocomposites in aqueous medium – a kinetic analysis of their catalytic activity for 4-nitrophenol reduction

Kaloti, Mandeep; Kumar, Anil; Navani, Naveen Kumar

doi:10.1039/c5gc00941c

Cited by 32 publications

(24 citation statements)

References 64 publications

(103 reference statements)

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“…The corresponding kinetic curves are shown in Fig. 10, which indicates that in all the cases the reaction follows zero-order kinetics similar to other reports in literature [60]. …”

Section: Resultssupporting

confidence: 85%

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

Kumar¹,

Sharma²,

Sharma³

et al. 2016

Beilstein J. Nanotechnol.

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Photocatalytic activity of semiconductor nanostructures is gaining much importance in recent years in both energy and environmental applications. However, several parameters play a crucial role in enhancing or suppressing the photocatalytic activity through, for example, modifying the band gap energy positions, influencing the generation and transport of charge carriers and altering the recombination rate. In this regard, physical parameters such as the support material and the irradiation source can also have significant effect on the activity of the photocatalysts. In this work, we have investigated the role of reduced graphene oxide (RGO) support and the irradiation source on mixed metal chalcogenide semiconductor (CdS–ZnO) nanostructures. The photocatalyst material was synthesized using a facile hydrothermal method and thoroughly characterized using different spectroscopic and microscopic techniques. The photocatalytic activity was evaluated by studying the degradation of a model dye (methyl orange, MO) under visible light (only) irradiation and under natural sunlight. The results reveal that the RGO-supported CdS–ZnO photocatalyst performs considerably better than the unsupported CdS–ZnO nanostructures. In addition, both the catalysts perform significantly better under natural sunlight than under visible light (only) irradiation. In essence, this work paves way for tailoring the photocatalytic activity of semiconductor nanostructures.

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“…The corresponding kinetic curves are shown in Fig. 10, which indicates that in all the cases the reaction follows zero-order kinetics similar to other reports in literature [60]. …”

Section: Resultssupporting

confidence: 85%

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

Kumar¹,

Sharma²,

Sharma³

et al. 2016

Beilstein J. Nanotechnol.

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“…It also explains the increased kinetic rates at different reaction states, and why a sluggish reaction presented in CuO‐a. These findings give a good interpretation that why the “lag phase” appears in the reduction process over metal oxides, such as Cu 2 O, Fe 2 O 3 and CuO …”

Section: Resultsmentioning

confidence: 54%

“…It can be as long as several minutes,, and has been considered as the time of surface restructuring of metal catalysts or the diﬀusion of 4‐NP before the reaction start ,. Thus, what is the potential factor triggering this instant catalysis (no induction time) over Bi(Cu)‐CNN hybrids that different from noble metals,, and metal oxides,?…”

Section: Resultsmentioning

confidence: 99%

Insight into the Catalytic Behavior in Nitroarenes Reduction over Non‐Noble Metals Modified Polymer Carbon Nitride

Qiu

et al. 2019

ChemistrySelect

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Revealing the catalytic mechanism and dynamic process in heterogeneous catalysis is fundamental and tremendous important. Here, non-noble metals (Bi, Cu, Cu 2 O or CuO) hybrided polymer carbon nitride nanosheets (CNN) were fabricated through ions intercalation processes. The prepared Bi-CNN hybrid exhibits moderate catalytic activity compared with Cu-CNN in 4-nitrophenol (4-NP) reduction. The kinetic rate constant and apparent active energy of Bi-CNN are 0.04 min À 1 (20°C) and 53.6 � 4.8 kJ mol À 1 , respectively. Cumodified CNN shows a rate of 0.65 min À 1 , which is 16 times higher than that of Bi-CNN and even higher than noble metal (Au, Ag)-CNN hybrids. More importantly, a new catalytic behavior that no delay time (usually reported by using noble metals and metal oxides) was observed in the 4-NP reduction over Bi-CNN and Cu-CNN hybrids. A possible catalytic mechanism elaborated this new catalytic phenomenon was proposed based on the chemical redox potentials. The CuO-CNN and Cu 2 O-CNN hybrids were further prepared to verify the proposed catalytic model. This work provides more insight into the mechanistic investigation of nitroarenes reduction over non-noble metal catalyst evolved photocatalytic systems. Results and DiscussionFigure 1 shows the procedure in preparation of non-noble metals modified CNN nano-hybrids. The bulk PCN was firstly exfoliated in the liquid under sonication. The acoustic cavita-[a] Dr.

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“…19-0629 or 39-1346). 31 The diffraction due to CSIO nanohybrids exhibited reduced intensity of all the peaks, matching that of IO without showing any extra peaks. The XRD pattern of CSIOAg demonstrated a further reduction in the intensity of peaks with respect to bare IO besides showing some additional peaks analogous with the reflections (111) and (200) matching to the cubic phase of Ag (JCPDS file no.…”

Section: Resultsmentioning

confidence: 86%

Sustainable Catalytic Activity of Ag-Coated Chitosan-Capped γ-Fe₂O₃ Superparamagnetic Binary Nanohybrids (Ag-γ-Fe₂O₃@CS) for the Reduction of Environmentally Hazardous Dyes—A Kinetic Study of the Operating Mechanism Analyzing Methyl Orange Reduction

Kaloti

Kumar

2018

ACS Omega

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The formation of binary nanohybrids consisting of environmentally benign components, γ-Fe 2 O 3 , chitosan (CS), and Ag (Ag-γ-Fe 2 O 3 @CS) (CSIOAg), containing very low concentration of Ag NPs (≤1.2 μM), has been reported. In the as-synthesized nanohybrids, the presence of γ-Fe 2 O 3 (8.5 ± 0.8 nm) and Ag (5.9 ± 0.5 nm) are revealed by optical, XRD, TEM, and XPS analyses, and their presence in cubic phase is determined by XRD and SAED measurements. The catalytic activity of CSIOAg has been analyzed by performing the reduction of certain toxic dyes. Under all kinetic conditions, the reaction is attended by an induction period, which is reduced upon increasing [Ag] and [Dye] in a specific concentration range, as well as temperature, suggesting restructuring of the surface prior to reduction. In case of methyl orange (MO), the reduction results in its cleavage to produce N , N -dimethyl-1,4-phenylenediamine and sodium sulfanilate in a significantly higher (>97%) yield in a bimolecular reaction between MO and BH 4 – . The duration of induction period is regularly decreased and the rate of reduction ( k app ) increases linearly with increasing Ag in the wide concentration range (0.03–2.4 μM). The reduction takes place with a second-order rate constant of 2.7 × 10 4 dm 3 mol –1 s –1 , which is >3.5-fold higher than that in the absence of chitosan (IOAg) under identical experimental conditions. The kinetics of reduction of MO is controlled by the nature and extent of its adsorption on the catalyst surface. The weaker binding between MO and Ag catalyst only allows its effective reduction. The XPS analysis of CSIOAg and IOAg containing the same amount of Ag (1.2 μM) showed its higher amount on the surface of CSIOAg (0.12%) as compared to that of IOAg (0.09%). Detailed kinetic analysis of MO reduction, performed under pseudo-kinetic conditions for both the nanohybrids revealed them to follow Langmuir–Hinshelwood kinetic model and exhibited the recyclability up to 10 cycles with fairly high reaction efficiency and TOF, suggesting it to be a sustainable green nanosystem.

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Synthesis of glucose-mediated Ag–γ-Fe₂O₃multifunctional nanocomposites in aqueous medium – a kinetic analysis of their catalytic activity for 4-nitrophenol reduction

Abstract: The synthesis of glucose-mediated Ag–γ-Fe2O3 nanocomposites in aqueous medium, exhibiting catalytic activity for 4-nitrophenol reduction to 4-aminophenol following the Langmuir–Hinshelwood mechanism at lower [Ag] (μM) (0.3, SPLAg; 6.4, SPHAg), is reported.

Cited by 32 publications

References 64 publications

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

Insight into the Catalytic Behavior in Nitroarenes Reduction over Non‐Noble Metals Modified Polymer Carbon Nitride

Sustainable Catalytic Activity of Ag-Coated Chitosan-Capped γ-Fe₂O₃ Superparamagnetic Binary Nanohybrids (Ag-γ-Fe₂O₃@CS) for the Reduction of Environmentally Hazardous Dyes—A Kinetic Study of the Operating Mechanism Analyzing Methyl Orange Reduction

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Synthesis of glucose-mediated Ag–γ-Fe2O3multifunctional nanocomposites in aqueous medium – a kinetic analysis of their catalytic activity for 4-nitrophenol reduction

Abstract: The synthesis of glucose-mediated Ag–γ-Fe2O3 nanocomposites in aqueous medium, exhibiting catalytic activity for 4-nitrophenol reduction to 4-aminophenol following the Langmuir–Hinshelwood mechanism at lower [Ag] (μM) (0.3, SPLAg; 6.4, SPHAg), is reported.

Cited by 32 publications

References 64 publications

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

Role of RGO support and irradiation source on the photocatalytic activity of CdS–ZnO semiconductor nanostructures

Insight into the Catalytic Behavior in Nitroarenes Reduction over Non‐Noble Metals Modified Polymer Carbon Nitride

Sustainable Catalytic Activity of Ag-Coated Chitosan-Capped γ-Fe2O3 Superparamagnetic Binary Nanohybrids (Ag-γ-Fe2O3@CS) for the Reduction of Environmentally Hazardous Dyes—A Kinetic Study of the Operating Mechanism Analyzing Methyl Orange Reduction

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Synthesis of glucose-mediated Ag–γ-Fe₂O₃multifunctional nanocomposites in aqueous medium – a kinetic analysis of their catalytic activity for 4-nitrophenol reduction

Sustainable Catalytic Activity of Ag-Coated Chitosan-Capped γ-Fe₂O₃ Superparamagnetic Binary Nanohybrids (Ag-γ-Fe₂O₃@CS) for the Reduction of Environmentally Hazardous Dyes—A Kinetic Study of the Operating Mechanism Analyzing Methyl Orange Reduction