Enhanced photocatalytic performance of Ag@TiO2 for the gaseous acetaldehyde photodegradation under fluorescent lamp

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 341; pp. 83 - 92
• Main Authors: Zeng, Qinglong, Xie, Xiaofeng, Wang, Xiao, Wang, Yan, Lu, Guanhong, Pui, David Y.H., Sun, Jing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2018
• Subjects: Ag@TiO2 core-shell heterostructure; Gaseous photocatalysis; Photocatalytic mechanism; Reactive radicals; Surface plasmon resonance; Reactive radicals; Surface plasmon resonance; Photocatalytic mechanism; Gaseous photocatalysis; Ag@TiO2 core-shell heterostructure
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2018.02.015

The outstanding performance of Ag nanowires@TiO2 composite and the thoroughly understanding of acetaldehyde photodegradation mechanism would cast light on the purposively design and optimization of TiO2-based catalysts. [Display omitted] •The Ag@TiO2 core-shell structure is beneficial to more light absorption and efficient charge separation.•The adsorptive property of acetaldehyde could reflect the effective reactive sites more straight in comparison to SBET.•The roles of reactive radicals were investigated through combining ESR tests and scavenger experiments together.•O2− played the predominant role in the photocatalytic process of acetaldehyde. The ever increasing problem of air pollution has provoked the research and development of highly-efficient photocatalysts. Herein, Ag nanowires@TiO2 composite photocatalyst with improved photocatalytic performance was fabricated by a facile one-step solvothermal procedure. The formation of one-dimensional Ag nanowires@TiO2 core-shell nanostructures could not only broaden the light-absorbing range of TiO2 catalysts through the surface plasmon resonance effect of Ag nanowires, but also enable the effective separation of photoinduced electron-hole pairs. Under the irradiation of a 260 W fluorescent lamp, the composite with 0.5 wt% Ag nanowires exhibited the highest photocatalytic activity in short contact time (4.8 min), and the corresponding gaseous acetaldehyde removal ratio was 72%, which was much higher than that of bare TiO2 (37%). The photocatalyst also showed ultrastable activity in the 15 weeks usage, which ensured their practical applications in the air purification field. An in-depth mechanism of the photodecomposition of acetaldehyde was proposed on the basis of the electron spin resonance (ESR) tests and the scavenger experiments. O2− reactive radicals was found to play a predominant role in the oxidation and decomposition of acetaldehyde. The outstanding performance of the composite materials and the thoroughly understanding of the reaction mechanism would cast light on the purposively design and optimization of TiO2-based catalysts.