Surface Plasmon Enhanced Photocatalysis of Au/Pt-decorated TiO2 Nanopillar Arrays.

Shuang Shuang,Ruitao Lv,Zhengjun Zhang,Zheng Xie

doi:10.1038/srep26670

Abstract

The low quantum yields and lack of visible light utilization hinder the practical application of TiO2 in high-performance photocatalysis. Herein, we present a design of TiO2 nanopillar arrays (NPAs) decorated with both Au and Pt nanoparticles (NPs) directly synthesized through successive ion layer adsorption and reaction (SILAR) at room temperature. Au/Pt NPs with sizes of ~4 nm are well-dispersed on the TiO2 NPAs as evidenced by electron microscopic analyses. The present design of Au/Pt co-decoration on the TiO2 NPAs shows much higher visible and ultraviolet (UV) light absorption response, which leads to remarkably enhanced photocatalytic activities on both the dye degradation and photoelectrochemical (PEC) performance. Its photocatalytic reaction efficiency is 21 and 13 times higher than that of pure TiO2 sample under UV-vis and visible light, respectively. This great enhancement can be attributed to the synergy of electron-sink function of Pt and surface plasmon resonance (SPR) of Au NPs, which significantly improves charge separation of photoexcited TiO2. Our studies demonstrate that through rational design of composite nanostructures one can harvest visible light through the SPR effect to enhance the photocatalytic activities initiated by UV-light, and thus realize more effectively utilization of the whole solar spectrum for energy conversion.

Highlights

Semiconductor photocatalysis has been considered as an alternative for the degradation of different pollutants and demonstrated to be a technically viable cleanup process[1]
Pu et al demonstrated those Au NPs, Au nanorods (NRs), and a mixture of Au NPs and NRs on the surface of TiO2 nanowire arrays could be prepared for effective photocatalysis and the activities were enhanced in both the UV and visible regions[15]
The peak intensity of Pt grows gradually as the deposition cycles increasing, indicating that more Pt NPs grows on the surface of TiO2 nanopillar arrays (NPAs)

Summary

Introduction

Semiconductor photocatalysis has been considered as an alternative for the degradation of different pollutants and demonstrated to be a technically viable cleanup process[1]. There are three main strategies to enhance the photocatalytic efficiency and visible light utilization of TiO2: (1) coupling with different semiconductors (e.g., TiO2/Cu2O3 and TiO2/WO34), (2) combining with noble metals (e.g., Au/TiO25, Pt/ TiO26 and Ag/TiO27,8), and (3) introducing dopants (e.g., oxygen defects[9], and sulfur[10], nitrogen[11]). Among them, combining with metal are a promising method to develop highly efficient visible light photocatalyst. The deposition of the metal on TiO2 can greatly improve its photoefficiency through the Schottky barrier conduction band (CB) electron trapping and consequent longer electron-hole pair lifetime. Hu et al reported a highly efficient Pt-doped TiO2 which have enhanced photocatalytic activity for NOx oxidation both under UV and visible light irradiation[12]. Excellent photocatalytic property and stability were achieved and the fabrication of TiO2 self-standing structures, which will be easier for recycling and facilitate their potential applications in solar energy-driven photocatalysis

Methods

Results

Conclusion