Near-Infrared-Triggered Nitrogen Fixation over Upconversion Nanoparticles Assembled Carbon Nitride Nanotubes with Nitrogen Vacancies

Yuxiang Zhu; Xianlin Zheng; Wenwen Zhang; Amanj Kheradmand; Shengshen Gu; Marcin Kobielusz; Wojciech Macyk; Haitao Li; Jun Huang; Yijiao Jiang

doi:10.1021/acsami.1c05683

Near-Infrared-Triggered Nitrogen Fixation over Upconversion Nanoparticles Assembled Carbon Nitride Nanotubes with Nitrogen Vacancies

ACS Appl Mater Interfaces. 2021 Jul 21;13(28):32937-32947. doi: 10.1021/acsami.1c05683. Epub 2021 Jul 6.

Authors

Yuxiang Zhu^{1

2}, Xianlin Zheng³, Wenwen Zhang¹, Amanj Kheradmand¹, Shengshen Gu¹, Marcin Kobielusz⁴, Wojciech Macyk⁴, Haitao Li⁵, Jun Huang⁵, Yijiao Jiang¹

Affiliations

¹ School of Engineering, Macquarie University, Sydney, New South Wales 2109, Australia.
² College of Chemical Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, P. R. China.
³ Department of Physics and Astronomy, Macquarie University, Sydney, New South Wales 2109, Australia.
⁴ Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387 Kraków, Poland.
⁵ School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia.

PMID: 34228426
DOI: 10.1021/acsami.1c05683

Abstract

Photocatalytic artificial fixation of N₂ to NH₃ occurs over NaYF₄:Yb,Tm (NYF) upconversion nanoparticles (NPs) decorated carbon nitride nanotubes with nitrogen vacancies (NYF/NV-CNNTs) in water under near-infrared (NIR) light irradiation. NYF NPs with a particle size of ca. 20 nm were uniformly distributed on the surface of NV-CNNTs. The NYF/NV-CNNTs with 15 wt % NYF exhibited the highest NH₃ production yield of 1.72 mmol L^-1 g_cat^-1, corresponding to an apparent quantum efficiency of 0.50% under NIR light illumination, and about three times higher the activity of the bare CNNTs under UV-filtered solar light. ¹⁵N isotope-labeling NMR results confirm that the N source of ammonia originates from the photochemical N₂ reduction. The spectroelectrochemical measurements reveal that NVs can greatly facilitate the photogenerated electron transfer without energy loss, while the presence of NYF NPs shifts both the deep trap state and the edge of conduction band toward a lower potential. Moreover, NYF NPs endow the photocatalyst with a NIR light absorption via the fluorescence resonance energy transfer process, and NVs have the ability to enhance the active sites for a stronger adsorption of N₂ and decrease the surface quenching effect of NYF NPs, which thus can promote the energy migration within the heterojunctions. This work opens the way toward full solar spectrum photocatalysis for sustainable ammonia synthesis under aqueous system.

Keywords: near-infrared light; nitrogen vacancy; photocatalytic nitrogen fixation; spectroelectrochemical method; upconversion nanoparticles.