Surface plasmon resonance enhanced visible-light-driven photocatalytic activity in Cu nanoparticles covered Cu2O microspheres for degrading organic pollutants

摘要

Micron-sized Cu2O with different coverage of Cu nanoparticles (NPs) on the sphere has been synthesized by a redox procedure. The absorption spectra show that Cu NPs induce the surface plasmon resonance (SPR) at the wavelength of 565 nm. Methylene blue (MB) photodegrading experiments under visible light display that the Cu2O-Cu-H2O2 system exhibits a superior photocatalytic activity to Cu2O-H2O2 or pure H2O2 with an evident dependency on Cu coverage. The maximum photodegradation rate is 88% after visible-light irradiating for 60 min. The role of the Cu NPs is clarified through photodegradation experiments under 420 nm light irradiation, which is different from the SPR wavelength of Cu NPs (-565 nm). By excluding the SPR effect, it proves that Cu SPR plays a key role in the photodegradation. Besides, a dark catalytic activity is observed stemming from the Fenton-like reaction with the aid of H2O2. The radical quenching experiments indicate that both.02- and.OH radicals contribute to the photocatalysis, while the dark catalysis is only governed by the.OH radicals, leading to a lower activity comparing with the photocatalysis. Therefore, with introducing Cu NPs and H2O2, the Cu2O-based photocatalytic activity could be significantly improved due to the SPR effect and dark catalysis. (C) 2016 Elsevier B.V. All rights reserved.