Ni2P‐Modified Ta3N5 and TaON for Photocatalytic Nitrate Reduction

Date
2020-04-28
Authors
Wei, Lin
Adamson, Marquix
Vela, Javier
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Altmetrics
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Ames Laboratory
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Chemistry
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Abstract

Self‐sustaining photocatalytic NO 3 ‐ reduction systems could become ideal NO 3 ‐ removal methods. Developing an efficient, highly active photocatalyst is the key to the photocatalytic reduction of NO 3 ‐ . In this work, we present the synthesis of Ni 2 P‐modified Ta 3 N 5 (Ni 2 P/Ta 3 N 5 ), TaON (Ni 2 P/TaON), and TiO 2 (Ni 2 P/TiO 2 ). Starting with a 2 mM (28 g/mL NO 3 ‐ ‐N) aqueous solution of NO 3 ‐ , as made Ni 2 P/Ta 3 N 5 and Ni 2 P/TaON display as high as 79% and 61% NO 3 ‐ conversion under 419 nm light within 12 h, which correspond to reaction rates per gram of 196 μmol g ‐1 h ‐1 and 153 μmol g ‐1 h ‐1 , respectively, and apparent quantum yields of 3–4%. Compared to 24% NO 3 ‐ conversion in Ni 2 P/TiO 2 , Ni 2 P/Ta 3 N 5 and Ni 2 P/TaON exhibit higher activities due to the visible light active semiconductor (SC) substrates Ta 3 N 5 and TaON. We also discuss two possible electron migration pathways in Ni 2 P/semiconductor heterostructures. Our experimental results suggest one dominant electron migration pathway in these materials, namely: Photo‐generated electrons migrate from the semiconductor to co‐catalyst Ni 2 P, and upshift its Fermi level. The higher Fermi level provides greater driving force and allows NO 3 ‐ reduction to occur on the Ni 2 P surface.

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This is the peer-reviewed version of the following article: Wei, Lin, Marquix Adamson, and Javier Vela. "Ni2P‐Modified Ta3N5 and TaON for Photocatalytic Nitrate Reduction." ChemNanoMat (2020), which has been published in final form at DOI: 10.1002/cnma.202000174. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Posted with permission.

Keywords
NO3- reduction, Ni2P photocatalysis, Ta3N5, TaON, clean water
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