A Blinking Mesoporous TiO2−x Composed of Nanosized Anatase with Unusually Long‐Lived Trapped Charge Carriers. (17th June 2020)

• Record Type: Journal Article
• Authors: Zhang, Tao; Low, Jingxiang; Yu, Jiaguo; Tyryshkin, Alexei M.; Mikmeková, Eliška; Asefa, Tewodros
• Is Part Of: Angewandte Chemie. Volume 132:Number 35(2020)
• Page Start: 15110
• Page End: 15117
• Publication Date: 2020-06-17
• Subjects: blinking nanoparticles -- carbon dioxide reduction -- long-lived charge carriers -- photocatalytic energy conversions -- titanium dioxide; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202005143
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: A mesoporous TiO2− x material comprised of small, crystalline, vacancy‐rich anatase nanoparticles (NPs) shows unique optical, thermal, and electronic properties. It is synthesized using polymer‐derived mesoporous carbon (PDMC) as a template. The PDMC pores serve as physical barriers during the condensation and pyrolysis of a titania precursor, preventing the titania NPs from growing beyond 10 nm in size. Unlike most titania nanomaterials, during pyrolysis the NPs undergo no transition from the anatase to rutile phase and they become catalytically active reduced TiO2− x . When exposed to a slow electron beam, the NPs exhibit a charge/discharge behavior, lighting up and fading away for an average period of 15 s for an extended period of time. The NPs also show a 50 nm red‐shift in their UV/Vis absorption and long‐lived charge carriers (electrons and holes) at room temperature in the dark, even long after UV irradiation. The NPs as photocatalysts show a good activity for CO2 reduction. Abstract : A blinking mesoporous TiO2− x is composed of small, crystalline, vacancy‐rich anatase nanoparticles. It shows unique optical, thermal, electronic, and photocatalytic properties. The nanoparticles continuously light up and fade away for an extended period of time under an electron beam. They also show long‐lived charge carriers (trapped electrons and holes) at room temperature in the dark, even long (30 min) after UV irradiation.