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

摘要

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 0.0644min(-1), 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 Ti3+-Ti4+ 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. Copyright (c) 2016 John Wiley & Sons, Ltd.