TiO2 nanotubes decorated with Au nanoparticles for Photocatalytic Hydrogen Generation under UV-Visible and Visible Light Irradiations.

Jean Claudio S Costa,Noelia Franco,Thiago André S Soares,Naythalla Angela M Saraiva,Marco Aurélio S Garcia,Johan Rene Gonzalez,Giovanna Machado

doi:10.1590/0001-3765202020200504

Jean Claudio S Costa, Noelia Franco + Show 5 more

Open Access

https://doi.org/10.1590/0001-3765202020200504

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Abstract

The development of stable and active TiO2 nanotubes (NTs) decorated with plasmonic gold nanoparticles (Au NPs) represents a strategy for charge-transfer processes improvements. However, organic capping ligands used for Au NPs synthesis usually remain on the surface of the metal, leading to poor Schottky junctions between Au and TiO2. Herein, we report on the synthesis of a nanotubular matrix of TiO2 decorated with gold without the need of ligands. The Au NPs mean diameter (12 nm) was similar to all the samples prepared, no matter the metal loading. Such materials enabled to use the metal as a cocatalyst for photogeneration of H2under UV and visible light irradiations. We found an optimum metal loading (2.6 wt% Au) that enabled an improvement of 760% on the H2 production when compared to the bare TiO2 NTs under UV-Vis irradiation. In addition, such catalyst was able to perform photogeneration of H2 under visible irradiation, which was not conceivable before the metal immobilization over the TiO2 NTs. The yield obtained was comparable to the observed when the catalyst was used under UV-Vis conditions. The produced materials were fully characterized by UV-Vis, XRD, TEM, and SEM.

Highlights

The world demand for fossil fuels has been increasing year-to-year since most of the global energy consumption is directly related to petroleum-derived products (Young et al 2017)
Considerable efforts have been doing in the development of more efficient catalysts for water splitting reactions; organic capping ligands used for Au NPs (Millstone et al 2009, Rycenga et al 2011) synthesis remain in the interface of the metal and the NTs, leading to poor Schottky junctions between Au and TiO2
The size distribution was found to be well described by a lognormal function and the narrow size distribution shows the robustness of the described approach for TiO2 NTs synthesis

Summary

Introduction

The world demand for fossil fuels has been increasing year-to-year since most of the global energy consumption is directly related to petroleum-derived products (Young et al 2017). Considerable efforts have been doing in the development of more efficient catalysts for water splitting reactions; organic capping ligands used for Au NPs (Millstone et al 2009, Rycenga et al 2011) synthesis remain in the interface of the metal and the NTs, leading to poor Schottky junctions between Au and TiO2.

Results

Conclusion