Electron deficient boron-doped amorphous carbon nitride to uphill N2 photo-fixation through π back donation

The photocatalytic Nitrogen fixation to NH3 by using water as a protonation source is a requisite renovation for life. Albeit, the activation and adsorption of robust NN is the bottleneck in NH3 synthesis. Here, we report an amorphous-wrinkled hollow-tubular electron-deficient boron-doped carbon nit...

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Published in:Applied catalysis. B, Environmental Environmental, 2023-02, Vol.321, p.122070, Article 122070
Main Authors: Ajmal, Sara, Rasheed, Aamir, Tran, Ngoc Quang, Shao, Xiaodong, Hwang, Yosep, Bui, Viet Q., Kim, Young Dok, Kim, Jeongyong, Lee, Hyoyoung
Format: Article
Language:English
Subjects:
Back-donation
Chemisorption
Metal-free
Metallomimetic
Nitrogen fixation
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Summary:The photocatalytic Nitrogen fixation to NH3 by using water as a protonation source is a requisite renovation for life. Albeit, the activation and adsorption of robust NN is the bottleneck in NH3 synthesis. Here, we report an amorphous-wrinkled hollow-tubular electron-deficient boron-doped carbon nitride (BCN) for improved photocatalytic N2 fixation via “σ donation and π back donation”. The electron-deficient B played synergetic roles to activate and stabilize the adsorbed N2 i.e. (i) It tunes the bandgap of CN for effective light absorption and charge transfer; (ii) The B-N coordination site polarizes chemisorbed N2 via electron pair acceptance; (iii) The filled sp2 orbital of B activates the N2 by π-back donation. Consequently, the photocatalytic performance of BCN-4 reaches 0.93mmolh−1g−1 with AQY of ∼13% (350 nm) and solar to NH3 conversion efficiency (SSCNH3) of 0.017%. The in situ DRIFT and DFT studies revealed that BCN exhibited spontaneous N2 adsorption and activation, followed by protonation of the adsorbed N2, with a negligible energy barrier. [Display omitted] •Salt template approach has been applied to synthesize a porous hollow tubular BCN.•Metallomimetic B chemisorbs and activates N2 in light along with bandgap adjustment.•The macro and mesopores in CN facilitate light absorption and charge transfer.•Excellent photocatalytic NRR rate (0.92 mmol) and AQY (13%) is achieved by B doping.•Electron deficient B selectively promotes N2 reduction by suppressing proton adsorption.
ISSN:0926-3373
1873-3883
DOI:10.1016/j.apcatb.2022.122070