Disordered Mesoporous TiO2−xNx+Nano‐Au: An Electronically Integrated Nanocomposite for Solar H2 Generation. Issue 2 (21st January 2014)

• Record Type: Journal Article
• Authors: Sivaranjani, Kumarsrinivasan; RajaAmbal, Sivaraman; Das, Tanmay; Roy, Kanak; Bhattacharyya, Somnath; Gopinath, Chinnakonda S.
• Is Part Of: ChemCatChem. Volume 6:Issue 2(2014:Feb.)
• Page Start: 522
• Page End: 530
• Publication Date: 2014-01-21
• Subjects: Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201300715
• Languages: English
• ISSNs: 1867-3880

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>We report on H<sub>2</sub> generation by photocatalysis driven by simulated white light by electronically integrated Au nanoparticles with multifunctional, disordered mesoporous TiO<sub>2−<italic>x</italic></sub>N<sub><italic>x</italic></sub> (Au‐NT) nanocomposites. Solar H<sub>2</sub> generation (1.5 mmol h<sup>−1</sup> g<sup>−1</sup>) from aqueous methanol has been demonstrated with Au‐NT nanocomposites. The water splitting activity of Au‐NT is attributed to the 21.1 ps lifetime of charge carriers observed from fluorescence lifetime measurements, which indicates a high electron‐injection efficiency from nano‐Au to the conduction band of TiO<sub>2</sub>, and hence charge separation as well as utilization. This is directly supported by the observation of a high photoluminescence emission intensity with Au‐NT that highlights the energy transfer from nano‐Au to TiO<sub>2</sub>. The p–n heterojunction observed between the Au (0 0 1) and TiO<sub>2</sub> (1 0 1) facets helps towards the higher charge separation and their utilization. A low mesochannel depth (<10 nm) associated with disordered mesoporous TiO<sub>2−<italic>x</italic></sub>N<sub><italic>x</italic></sub> helps the charge carriers to move towards the surface for redox reactions and hence charge utilization. Visible‐light absorption, as a result of the surface plasmon resonance of nano‐Au, is observed in a broad range between 500 and 750 nm, which helps in harvesting visible‐light photons. Finally, electronically integrated nano‐Au with TiO<sub>2−<italic>x</italic></sub>N<sub><italic>x</italic></sub> in Au‐NT is evident from Raman and X‐ray photoelectron spectroscopy measurements. All of these factors help to achieve a high rate of H<sub>2</sub> production. It is likely that a higher rate of H<sub>2</sub> production than that reported here is feasible by strategically locating Au clusters in porous TiO<sub>2</sub> to generate hot spots through electronic integration.</p> </abstract>