Photocatalytic Properties of MOF-derived ZnO/C, Ag/ZnO/C Porous Composite Materials

doi:10.15541/jim20150201

Abstract

Abstract:

Two photocatalytic materials, ZnO/C and Ag/ZnO/C, were synthesized by high temperature heat-treatment and wet-chemical methods using a typical metal-organic framework (MOF-5) as precursor. The samples were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), X-ray energy dispersive spectroscope (EDS), and UV-Vis diffuse reflection spectroscope (UV-Vis DRS), respectively. After heat-treatment under nitrogen, the initial morphology of MOF-5 is mostly retained. As a result, relatively high surface area up to 390 m²/g of ZnO/C and 232 m²/g of Ag/ZnO/C are realized. The size of Ag particles loaded on Ag/ZnO/C is about 30 nm. The photocatalytic efficiencies of both ZnO/C and Ag/ZnO/C composites on photo-degradation of methylene blue (MB) are higher than that of commercial TiO₂ powder (Degussa P25). Ag/ZnO/C possesses even higher photocatalytic ability, repeatability and stability than does ZnO/C. The results strongly suggest that high temperature heat-treatment of the MOF properly followed by moderate silver doping is a facile way to improve the photocatalytic properties.

Key words: metal-organic framework, dopping, ZnO, modification, photocatalysis

CLC Number:

TQ132

GUO Yan-Rong, CHANG Wei, ZHANG Wen, WANG Hui. Photocatalytic Properties of MOF-derived ZnO/C, Ag/ZnO/C Porous Composite Materials[J]. Journal of Inorganic Materials, 2015, 30(12): 1321-1326.

Figures/Tables 8

Fig. 1 XRD patterns of (a) MOF-5 and (b) derivatives

Fig. 2 SEM images of samples (a) ZnO/C, (b) AZC-1, (c) Ag/MOF-5, (d) AZC-2, and corresponding EDS patterns for (b) and (d)

Table 1 Physical property of the samples

Sample	MOF-5	ZnO/C	AZC-1	Ag/MOF-5	AZC-2
BET/(m²•g^-1)	766	390	232	21	21
Pore volume/(mL•g^-1)	0.477	0.599	0.568	0.145	0.076

Fig. 3 UV-Vis diffuse reflection spectra of composite materials

Fig. 4 Absorption curves for different samples of methylene blue

Fig. 5 Photo-degradation curves of methylene blue for different samples

Fig. 6 Recycling uses of the samples for Methylene Blue (MB)

Fig. 7 Scheme diagram of photodegradation mechanism of AZC-1[17]

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