NH2-UiO-66(Zr) with fast electron transfer routes for breaking down nitric oxide via photocatalysis

• Published in: Applied catalysis. B, Environmental Environmental, 2020-06, Vol.267, p.118687, Article 118687
• Main Authors: Chen, Xiaolang, Cai, Yong, Liang, Rui, Tao, Ying, Wang, Wenchao, Zhao, Jingjing, Chen, Xiaofeng, Li, Hexing, Zhang, Dieqing
• Format: Article
• Language: English
• Subjects: Breaking down; Carrier density; Charge transfer; Copper; CuI/II; Durability; Electron transfer; Electrons; Introduced species; Irradiation; Light irradiation; Metal organic frameworks; Nitric oxide; NO oxidation; Oxidation; Photocatalysis; Photooxidation; Radiation; Zirconium
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.118687

CuI/CuII enhanced NH2-UiO-66 (Zr) photocatalysts were developed for effectively oxidizing NO indoor gas (500 ppb) under visible-light irradiation through the ligand to linker metal charge transfer (LLMCT) pathway. [Display omitted] •Ligand to linker metal charge transfer (LLMCT) pathway in (NH2-UiO-66(Zr).•Fast photogenerated electrons transferring from organic linkers to Cu species.•High carrier density value (24.4*1021 cm−3) and long photogenerated charge lifetime (78.2 ps).•Excellent photocatalytic oxidation of low-concentration (550 ppb) of NO indoor gas. MOFs-based photocatalysts always suffer from poor performance owing to its slow charge transfer. Herein, transient metal Cu (CuI/II) species were introduced to NH2-UiO-66(Zr) (Cu-NU0) via in-situ partial reduction of CuII ions to CuI. A ligand to linker metal charge transfer (LLMCT) pathway in MOFs was constructed for accelerating the photogenerated electrons transfer from organic linkers to Cu species, greatly enhanced increasing both the carrier density value and the separation efficiency of photogenerated carriers. A longer photogenerated charge lifetime (78.2 ps) was obtained and about 4 times higher than that of Cu-NU0. More photogenerated electrons in the Cu coordinated MOFs (Cu-NU7) were transferred to the outside surface of the MOFs, producing O2− for the photocatalytic oxidation of low-concentration (550 ppb) of NO indoor flow gas. An 88 % removal rate of NO under visible-light irradiation (λ > 420 nm) was obtained and well maintained up to 24 h with excellent durability.