Electrochemical sensing mechanism of ammonium ions over an Ag/TiO2 composite electrode modified by hematite

01 natural sciences 0104 chemical sciences
DOI: 10.1039/d3cc00240c Publication Date: 2023-02-02T16:03:03Z
ABSTRACT
Here, we demonstrate a new electrochemical sensing mechanism of ammonium ions (NH4+) involving two-electron oxygen reduction reaction (ORR) and hydrazine reaction. The NH4+ are electrooxidized to by H2O2 derived from the ORR over self-supporting Ag/TiO2 nanotube array composite electrode modified hematite (Ag/Fe2O3/TNTs). Ag/Fe2O3/TNT sensor exhibits high sensitivity 1876 µA mM-1 cm-2 with detection limit 0.18 µM under non-alkaline conditions, short response time 3 s, good reproducibility, fine selectivity among various interferents, is also successfully used in real water bodies display accuracy. Furthermore, this has certain universality range Ag (main catalyst)/transition metal oxide (cocatalyst)/TNT systems. This work offers design basis for urgently needed ammonia nitrogen sensors.
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