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Origin of superior photocatalytic activity in rutile TiO2 hierarchical microspheres: The dominate role of “microcavity” structure

Paper ID Volume ID Publish Year Pages File Format Full-Text
39689 45831 2014 7 PDF Available
Title
Origin of superior photocatalytic activity in rutile TiO2 hierarchical microspheres: The dominate role of “microcavity” structure
Abstract

•Hierarchical TiO2 microspheres assembled by nanowires bundles were synthesized.•Annealing and ultrasonic irradiation had great effect on the structures of TiO2.•The microcavity structure of hierarchical TiO2 was destroyed upon both treatments.•The disappearance of microcavity structure reduced the photocatalytic activity.

This paper aims to investigate the role that hierarchical structure plays in photocatalytic process. Hierarchical rutile TiO2 microspheres assembled by nanowires bundles were initially synthesized and then treated by thermal annealing or ultrasonic irradiation. Various technologies including SEM, XRD, DRS, and N2 sorption were employed to investigate the effect of post-treatments on the microstructures of TiO2 samples. The results revealed that annealing treatment caused obvious growth of particle size, decreased surface area and pore volume, and weakened optical absorbance, while ultrasonic irradiation had little influence on these properties. However, both annealing treatment and ultrasonic irradiation seriously destroyed the microcavity structure which existed in between the roughly parallel nanowires of hierarchical TiO2 microspheres. The existence of microcavity in these TiO2 hierarchical microspheres was proved to be crucial to the photoactivity toward degradation of methyl orange (MO). It has been proposed that the microcavities could act as microcapacitors for electronic storage and therefore contribute to a high separation efficiency of photogenerated electron–hole pairs. On the basis of ESR and active species scavenger experiments, h+ was found to be the primary active species in MO degradation while O2− slightly promoted the degradation efficiency via the formation of OH. This finding is of great significance for the design of efficient photocatalytic materials with potential applications in solving worldwide energy crisis and environmental pollution.

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Keywords
Hierarchical; Rutile; TiO2; Microcavity; Photocatalysis
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Origin of superior photocatalytic activity in rutile TiO2 hierarchical microspheres: The dominate role of “microcavity” structure
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 478, 20 May 2014, Pages 204–210
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us