Photoinduced electron transfer and photodegradation of malonic acid at Au/TiO2 investigated by in situ ATR-IR spectroscopy

TiO2 coated Au nanoparticles were synthesized and characterized by TEM, XPS and XRD. It was found that the Au nanoparticles were coated with TiO2 thus forming a core–shell structure. Electron transfer, adsorption and photodegradation of malonic acid on the catalyst were investigated by in situ attenuated total reflection infrared (ATR-IR) spectroscopy. Malonic acid adsorbed and underwent photodegradation efficiently in air and nitrogen atmosphere under UV light illumination on the prepared catalyst. As intermediate species oxalate was observed on the catalyst surface during the photodegradation of malonic acid. The Au nanoparticles accelerate the degradation of malonic acid by capturing the conduction band electrons of TiO2. The ATR spectra also reveal interface electron transfer from Au nanoparticles to TiO2 under visible light illumination and from TiO2 to Au nanoparticles under UV illumination.

Graphical abstractPhotoinduced electron transfer and photodegradation of malonic acid at Au/TiO2.Figure optionsDownload full-size imageDownload high-quality image (175 K)Download as PowerPoint slideHighlights► Photodegradation of dicarboxylic acids on TiO2 and Au@TiO2 was studied. ► ATR-IR technique was used to monitor the adsorbed species and shallow trap electrons on the catalyst. ► Electrons are transferred from Au nanoparticles to TiO2 under visible light illumination. ► Electrons are transferred from TiO2 to Au nanoparticles under UV illumination. ► The effect of electron transfer on the catalysis is revealed.