Campus Units
Chemistry, Physics and Astronomy, Ames Laboratory
Document Type
Article
Publication Version
Submitted Manuscript
Publication Date
2020
Journal or Book Title
ACS Catalysis
Volume
10
First Page
3618
Last Page
3628
DOI
10.1021/acscatal.9b05338
Abstract
Motivated by increased awareness about nitrate contamination of surface waters and its deleterious effects in human and animal health, we sought an alternative, non-noble metal catalyst for the chemical degradation of nitrate. First row transition metal phosphides recently emerged as excellent alternatives for hydrogen evolution and hydrotreating reactions. We demonstrate that a key member of this family, Ni2P, readily hydrogenates nitrate (NO3–) to ammonia (NH3) near ambient conditions with very high selectivity (96%). One of the few non-precious metal-based catalysts for this transformation, and among ca. 1% of catalysts with NH3 selectivity, Ni2P can be recycled multiple times with limited loss of activity. Both nitrite (NO2–) and nitric oxide (NO) intermediates are also hydrogenated. Density functional theory (DFT) indicates that—in the absence of a catalyst—nitrite hydrogenation is the reaction bottleneck. A variety of adsorbates (H, O, N, NO) induce surface reconstruction with top-layer Ni-rich surface stoichiometry. Critically, H saturation coverage on Ni2P(001) is only ca. 3 nm–2, significantly less than that on Pd(111) and Ni(111) of ca. 15–18 nm–2, which may play a key role in allowing coadsorption of NOx–. The ability of Earth-abundant, binary metal phosphides such as Ni2P to catalyze nitrate hydrogenation could transform and help us to better understand the basic science behind catalytic hydrogenation and, in turn, advance the next generation of oxyanion removal technologies.
Copyright Owner
American Chemical Society
Copyright Date
2020
Language
en
File Format
application/pdf
Recommended Citation
Wei, Lin; Liu, Da-Jiang; Rosales, Bryan A.; Evans, James W.; and Vela, Javier, "Mild and Selective Hydrogenation of Nitrate to Ammonia in the Absence of Noble Metals" (2020). Chemistry Publications. 1216.
https://lib.dr.iastate.edu/chem_pubs/1216
Supplemental Information
Comments
This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Catalysis, copyright © American Chemical Society after peer review. To access the final edited and published work see DOI:10.1021/acscatal.9b05338. Posted with permission.