Visible Light-Induced Reactivity of Plasmonic Gold Nanoparticles Incorporated into TiO2 Matrix towards 2-Chloroethyl Ethyl Sulfide

Wesley Gordon,Spencer Giles,Monica Mcentee,Alexander Govorov,Olga Baturina,Alex Balboa,Oscar Ávalos-Ovando,Albert Epshteyn

doi:10.3390/cryst11060659

Abstract

Inexpensive strategies for efficient decontamination of hazardous chemicals are required. In this study, the effect of visible light (λ > 400 nm) on the decomposition of 2-chloroethyl ethyl sulfide (2-CEES, a sulfur mustard (HD) simulant) on Au/TiO2 photocatalyst under anaerobic and aerobic conditions has been investigated in situ by diffuse reflectance infrared Fourier –transformed spectroscopy (DRIFTS). Under anaerobic conditions, 2-CEES partially desorbs from the Au/TiO2 surface likely due to the photothermal effect, induced by photo-excited plasmonic Au nanoparticles. In the aerobic experiment, no visible light effect is observed. We attribute this behavior to 2-CEES consumption by hydrolysis to 2-ethylthio ethanol in the dark, prior to visible light excitation. Oxygen activates water molecules in the dark, resulting in accelerated 2-CEES hydrolysis.

Highlights

We investigate the effect of visible light on the activity of the Au/TiO2 photocatalyst toward the decomposition of a hazardous chemical 2-chloroethyl ethyl sulfide (CEES) under anaerobic and aerobic conditions
Au nanoparticles (NPs) exhibit a localized surface plasmon resonance (LSPR) in the visible region, which can be utilized for driving photochemical reactions at the plasmonic nanoparticle/ semiconductor interface [1,2,3,4,5,6,7,8,9]
In agreement with our previous report [31], we find that 2-CEES undergoes hydrolysis to 2-ethylthio ethanol in the dark, prior to visible light excitation both in anaerobic and aerobic conditions

Summary

Introduction

We investigate the effect of visible light on the activity of the Au/TiO2 photocatalyst toward the decomposition of a hazardous chemical 2-chloroethyl ethyl sulfide (CEES) under anaerobic and aerobic conditions. Utilizing the energy of sunlight and oxygen from air as an oxidizing agent for photooxidation of hazardous chemicals to innocuous reaction products would be the first step toward the realization of the concept of an environmentally sustainable process. 520 nm), which can be utilized for driving photochemical reactions at the plasmonic nanoparticle/ semiconductor interface [1,2,3,4,5,6,7,8,9]. Analysis of oxidation of small molecules at the Au/TiO2 catalyst revealed that O2 activation at the interface plays a key role in the enhancement of the reaction rate [25,26,27].

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Results

Conclusion