One‐pot self‐assembly and photoreduction synthesis of silver nanoparticle‐decorated reduced graphene oxide/MIL‐125(Ti) photocatalyst with improved visible light photocatalytic activity

Abstract

e In recent years, tremendous research efforts have been made towards developing metal-organic framework (MOF)-based composites for photocatalytic applications. In this work, bipyramid-like MIL-125(Ti) frustum enwrapped with reduced graphene oxide (rGO) and dispersed silver nanoparticles (Ag NPs) was fabricated using an efficient one-pot self-assembly and photoreduction strategy. The as-obtained materials were characterized using field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption isotherms, and X-ray photoelectron, ultraviolet-visible diffuse reflectance and photoluminescence spectroscopies. It is found that the as-prepared Ag/rGO/MIL-125(Ti) ternary hybrids have large surface area, microporous structure, enhanced visible light absorption and prolonged lifetime of charge carriers. Compared with pure MIL-125(Ti) and its binary counterparts, the ternary composite exhibits more efficient photocatalytic performance for Rhodamine B (RhB) degradation from water under visible light irradiation. The photodegradation rate of RhB on Ag/rGO/MIL-125(Ti) is 0.0644 min À1, which is 1.62 times higher than that of the pure MIL-125(Ti). The improved photocatalytic performance is ascribed to the indirect dye photosensitization, the Ag NP localized surface plasmon resonance, the Ti 3+ -Ti 4+ intervalence electron transfer and the synergistic effect among MIL-125(Ti), Ag NPs and rGO. Ag NPs serve as an efficient 'electron reservoir' and rGO as an electron transporter and collector. Therefore, this work provides a new pathway into the design of MOF-based composites for application in environmental and energy fields.

Bimetallic Fe/Ti‐Based Metal–Organic Framework for Persulfate‐Assisted Visible Light Photocatalytic Degradation of Orange II

“…Concurrently, the Ti 2 p , C 1s, N 1s, and O 1s XPS spectra of Ti‐MOF‐NH 2 are illustrated in Figure S3 . High‐resolution XPS spectrum of the Ti 2 p ( Figure S3a ) electrons and binding energies of Ti 2 p 3/2 and Ti 2 p 1/2 peaks were located at 458.7 and 464.5 eV, respectively, indicating that the titanium bound to oxygen remained in oxidation state IV for the titanium‐oxo cluster . Figure S3b demonstrated that the high‐resolution XPS spectrum of C 1s was the same as that of the Fe‐MOF‐NH 2 , of which the four C–C/C–H, C–N, N–C=O, and –COO groups were found.…”

Effects of ligand functionalization on the photocatalytic properties of titanium-based MOF: A density functional theory study

“…MOFs have many excellent properties that are different from those of traditional porous and crystal materials, such as nanoscale controlled pore structure, high surface area, and metal-organic ligand combination diversity, etc. Correspondingly, MOF has a variety of potential applications in many fields, including gas separation and storage, [1][2][3][4] catalysis, [5][6][7] biochemistry 8 and so on. Especially, many investigations have demonstrated that MOF materials are promising catalysts in photocatalysis.…”

“…Especially, many investigations have demonstrated that MOF materials are promising catalysts in photocatalysis. 5,6,[9][10][11][12][13][14][15][16] As one of the most popular MOF, 1,[5][6][7] the titanium-based MIL-125 can catalyze the oxidation of alcohols to aldehydes under the UV irradiation, indicating that MIL-125 is an active photocatalyst. 10 However, because of the large optical band gap (3.6 eV), 10 MIL-125 is only active under UV irradiation.…”

NiTiO3/Ag3PO4 composites with improved photocatalytic activity under visible-light irradiation

“…Accordingly, it is imperative to develop efficient visible-light photocatalysts. Based on this, as is currently required, many visible-light photocatalysts have emerged, such as BiVO 4 [6], g-C 3 N 4 [7,8], BiOI [9], Ag 3 VO 4 [10], Ag 3 PO 4 [11] and graphene-based materials [12,13].…”