Low-Temperature Synthesis of Anatase TiO2 Nanoparticles with Tunable Surface Charges for Enhancing Photocatalytic Activity

About the Authors:

Ye Li

Affiliations College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China, Beijing Key Laboratory for Green Catalysis and Separation, Beijing, PR China

Zhenping Qin

Affiliation: College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China

Hongxia Guo

* E-mail: [email protected]

Affiliations College of Materials Science and Engineering, Beijing University of Technology, Beijing, China, Beijing Key Laboratory for Green Catalysis and Separation, Beijing, PR China

Hanxiao Yang

Affiliation: College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China

Guojun Zhang

Affiliation: College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China

Shulan Ji

Affiliations College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, China, Beijing Key Laboratory for Green Catalysis and Separation, Beijing, PR China

Tingying Zeng

Affiliation: MIT, Elect. Res. Lab, Cambridge, Massachusetts, United States of America

Introduction

Photocatalytic degradation is an efficient and economical method to totally decompose organic contaminants into benign substances [1]–[2]. Titanium dioxide (TiO₂) nanocrystal has attracted much attention as a photocatalyst due to its photostability, nontoxicity, high activity and relatively low cost [3]. TiO₂ has three crystalline forms: rutile, anatase and brookite [4]. Anatase titania usually exhibits higher photocatalytic activity than rutile and brookite, owing to its higher density of localized states, the surface-adsorbed hydroxyl radicals and slower charge carrier recombination [5]–[7]. Much work has been reported for preparation of anatase TiO₂, such as thermolysis [8]–[9], sol-gel [10]–[11], ultrasonic technique [12], solvothermal [13] and hydrothermal method [14]–[15], by which the resulted particles have to be annealed at suitable temperature to obtain crystalline TiO₂ with anatase phases. The annealing process at relatively high temperature would inevitably lead to particles agglomeration and hence reduction of their specific surface area [16]–[17]. Therefore, the low temperature methods for preparation of anatase TiO₂ particles and films attract much attention, due to the fact that calcinations step can be eliminated. Mesoporous aggregates of anatase TiO₂ were obtained by controlled hydrolysis reaction of titanium tetrabutoxide in non-aqueous media, isopropanol, and then aging at ambient conditions for more than 120 days [18]. Gao et al. have synthesized the superfine TiO₂ nanocrystals with tunable anatase/rutile ratios in aqueous ethanol solution by “low temperature dissolution–reprecipitation...