Graphitic nitrogen in carbon catalysts is important for the reduction of nitrite as revealed by naturally abundant¹⁵N NMR spectroscopy

Abstract

Metal-free nitrogen-doped carbon is considered as a green functional material, but the structural determination of the atomic positions of nitrogen remains challenging. We recently demonstrated that directly-excited solid state 15N...

Atomic-Level Understanding for the Enhanced Generation of Hydrogen Peroxide by the Introduction of an Aryl Amino Group in Polymeric Carbon Nitrides

“…Indeed, among the nuclei relevant for this study, nitrogen is the most challenging one. This is because the NMR active isotope 14 N exhibits severe spectral broadening due to quadrupolar interaction (with exceptions for highly symmetric environments), and the other active isotope 15 N suffers from low natural abundance and, therefore, sensitivity, which often requires isotope enrichment. However, it has been shown that 15 N NMR is capable of delivering crucial information for the nitrogen inserted in materials .…”

Reaction pathways on N-substituted carbon catalysts during the electrochemical reduction of nitrate to ammonia

“…These results imply good catalytic stability during the NO 3 RR for the NDC-800 catalyst, which is consistent with previous carbon-based materials studies. 59,73…”

“…catalyst, which is consistent with previous carbon-based materials studies. 59,73 To verify the source of ammonia, the electrolyte without NO 3 − was also tested as a control experiment for the electrochemical NO 3 RR. The result showed that the electrochemical NO 3 RR measured in blank Na 2 SO 4 electrolyte yielded a negligible concentration of NH 4 + (Fig.…”

“…31,56,57 The metalfree cellulose-derived NDC material as a perspective green electrocatalyst has received particular attention for electrocatalytic applications due to its significant electrical conductivity and catalytic activity that can be applied in the NO 3 RR. 12,15,58 We have recently shown that graphitic N is important for NDC-800 in the electrochemical reduction of nitrite anions, 59 but the role of defects and the potential mechanisms in reduction of nitrate anions on carbon catalysts still remain elusive.…”

High-efficiency electrosynthesis of ammonia with selective reduction of nitrite over an Ag nanoparticle-decorated TiO2 nanoribbon array

“…However, the electrochemical NO 2 − reduction reaction (NO 2 − RR) involves a complex six-electron pathway with various possible by-products (N 2 H 4 , N 2 , and H 2 ), thus requiring highly active catalysts for selective NO 2 − -to-NH 3 conversion. 18–27…”