Microwave-assisted synthesis of Ag-doped MOFs-like organotitanium polymer with high activity in visible-light driven photocatalytic NO oxidization

doi:10.1016/j.apcatb.2015.02.003

Applied Catalysis B: Environmental

Volumes 172–173, August 2015, Pages 46-51

https://doi.org/10.1016/j.apcatb.2015.02.003 Get rights and content

Highlights

•
A novel Ag-doped MOF-like organotitanium polymer.
•
Ag NPs-assisted assembly of NH₂-MOP(Ti) polymer.
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Promoted light harvesting and fast electron transfer rate.
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Enhanced photocatalytic activity and strong durability for breaking down nitric oxide.

Abstract

A novel Ag-doped MOF-like organotitanium polymer (Ag@NH₂-MOP(Ti)) was synthesized via a microwave-assisted coordination and polymerization reaction with 2-aminoterephthalic acid (H₂ATA) and tetra-n-butyl titanate (Ti(OC₄H₉)₄), followed by the crystal growth and assembly onto Ag nanoparticles (NPs). This Ag@NH₂-MOP(Ti) exhibited excellent activity in visible-light driven photocatalytic NO oxidization, much higher than N-doped TiO₂ by two times. The NH₂-MOP(Ti) absorbed visible lights to generate photoelectrons and holes, accompanied by producing HO radical dot and O₂⁻ active sites for the subsequent NO oxidation into NO₃⁻. The Ag NPs allowed assembly of NH₂-MOP(Ti) polymer favoring light absorbance via multiple reflections and also facilitated photoelectrons transfer to reduce photoelectron–hole recombination, leading to the enhanced photocatalytic activity for NO oxidation and inactivating bacteria. Moreover, it could be used repetitively owing to the high stability.

Graphical abstract

Introduction

Air pollution becomes crucial problem in damaging the human health and the sustainable development of both society and economy. The sweep-gas from cars, power-plants, chemical industries and plant-burning usually contains nitrogen oxides (NO_x), sulfur oxides (SO_x), carbon monoxide (CO), persistent organic pollutants (POPs) and even mercury (Hg), which were considered as the most important reason for the air pollution, which were considered as the most important reason for the air pollution, which were considered as the most important reason for the air pollution [1], [2], [3] Thus, removal NO_x is one of common targets in treating air pollution [4]. Recently, photocatalysis has received increasing attention in environmental cleaning [5], [6], [7] and the photocatalytic NO oxidization represents one of the most promising ways in removing NO_x owing to the simple operation, low cost, high efficiency, and strong durability etc. [8], [9]. TiO₂ without or with dopants like non-metals, metals, metal ions, and oxides are frequently employed for photocatalytic NO oxidation under UV lights irradiation [9], [10], [11], but they usually display much lower activities than thermal catalysts. Under visible-light irradiation, they exhibit extremely low activity in photocatalytic NO oxidation [8], which limits their utilization of solar lights. Recently, metal-organic frameworks (MOFs) become more and more attractive owing to their unique properties and wide applications in sensor, adsorption, catalysis, and energy storage etc. [12], [13], [14]. Their applications in photocatalytic dye degradation, water splitting, and CO₂ reduction have been widely reported, but most of them exhibit very poor activities [12], [15], [16], [17], [18]. No report has been found so far for the photocatalytic NO oxidation on MOFs. Herein, we reported for the first time a new Ag-loaded MOFs-like organotitanium polymer prepared by coordination and polymerization reaction between 2-aminoterephthalic acid and Tetra-n-butyl titanate in the presence of Ag NPs under microwave irradiation. The unique coordination bond in MOF-like network absorbed visible lights to generate photoelectrons and holes. The Ag NPs promoted the light harvesting and also facilitated photoelectron transfer to retard their recombination with holes. As a result, the as-prepared Ag@NH₂-MOP(Ti) exhibited excellent photocatalytic activity in both NO oxidization and inactivating bacteria under visible lights irradiation.

Section snippets

Materials

2-aminoterephthalic acid (H₂ATA) was obtained from Sigma–Aldrich. Tetra-n-butyl titanate (Ti(OC₄H₉)₄) and Ag nanoparticles (NPs) were obtained from Aladdin. N,N-dimethylformamide (DMF), methanol (MeOH), and anhydrous ethanol (EtOH) were supplied by Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). All materials were used as received without further purification.

Sample preparation

In a typical run of synthesis, 1.1 g of H₂ATA was added into a solution containing 18 mL of DMF and 2.0 mL of EtOH and stirred at 25

Results and discussion

As shown on Fig. 1, the NH₂-MOP(Ti) displayed similar FTIR spectrum to the NH₂-MIL-125(Ti) [12]. No significant vibration bands at 3059 and 2524 cm⁻¹ indicative of the COOH group in the original H₂ATA molecule were observed. However, two vibration bands at 3500–3150 cm⁻¹ characteristic of the single bond NH₂ group in H₂ATA molecule were still reserved, which were overlapped with the strong vibration band of the OH group around 3350 cm⁻¹. Meanwhile, the special vibration peaks at 962, 892 and 770 cm⁻¹

Conclusions

This work developed a novel MOFs-like organotitanium polymer via Ti⁴⁺–H₂ATA coordination in cross-linked network under microwave irradiation. The as-prepared Ag@NH₂-MOP(Ti) exhibited very high activity and strong durability in visible lights driven photocatalytic NO oxidation and inactivation of bacteria. The NH₂-MOP(Ti) was activated by visible lights to generate photoelectrons and holes, followed by producing O₂⁻ and HO radical dot active species. The Ag nanoparticles promoted light harvesting and

Acknowledgements

This work was supported by NSFC (21477079, 21207090, 21237003, 21261140333), PCSIRT (IRT1269), Shanghai Government (14JC1402500, 15QA1403300h), the Doctoral Program of Higher Education (20123127120009), and Shanghai Normal University (DXL122and S30406).

References (32)

J. Lasek et al.
J. Photochem. Photobiol. C
(2013)
M. Signoretto et al.
Appl. Catal. B
(2010)
J.S. Dalton et al.
Environ. Pollut.
(2002)
J.C.S. Wu et al.
J. Catal.
(2006)
S.P. Chenakin et al.
J. Catal.
(2014)
J.E. Gonçalves et al.
J. Electron Spectrosc.
(2001)
G.X. Zhang et al.
Carbon
(2008)
K.P. Wang et al.
Carbohydr. Res.
(2014)
D.Q. Zhang et al.
Appl. Catal. B
(2014)
Z.B. Wu et al.
Chemosphere
(2009)

S. Roy et al.

Chem. Rev.

(2009)

X. Huang et al.

Environ. Sci. Technol.

(2011)

G. Lammel et al.

Environ. Sci. Technol.

(2013)

P. Granger et al.

Chem. Rev.

(2011)

J. Schneider et al.

Chem. Rev.

(2014)

M.R. Hoffmann et al.

Chem. Rev.

(1995)

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¹: These authors contributed equally to this work.

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Microwave-assisted synthesis of Ag-doped MOFs-like organotitanium polymer with high activity in visible-light driven photocatalytic NO oxidization

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Materials

Sample preparation

Results and discussion

Conclusions

Acknowledgements

J. Photochem. Photobiol. C

Appl. Catal. B

Environ. Pollut.

J. Catal.

J. Catal.

J. Electron Spectrosc.

Carbon

Carbohydr. Res.

Appl. Catal. B

Chemosphere

Chem. Rev.

Environ. Sci. Technol.

Environ. Sci. Technol.

Chem. Rev.

Chem. Rev.

Chem. Rev.