Open AccessElectrochemical Gas Sensor Integrated with Vanadium Monoxide Nanowires for Monitoring Low Concentrations of Ammonia Emission
Author(s) -
Praveen Kumar Sekhar,
David Graf,
Olusola Ojelere,
Tonmoy Kumar Saha,
Manjurul Ahsan Riheen,
Sanjay Mathur
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ab7114
Subject(s) - nanowire , vanadium , ammonia , electrochemistry , electrochemical gas sensor , monoxide , materials science , inorganic chemistry , platinum , adsorption , carbon monoxide , electrode , analytical chemistry (journal) , chemical engineering , nanotechnology , chemistry , catalysis , environmental chemistry , organic chemistry , engineering
An electrochemical sensor for the detection of extremely low concentration of ammonia (1 part per billion, ppb) was fabricated by integrating vanadium monoxide (VO x ; x = 0.8–1.2) nanowires on the platinum electrodes. The nanowire-based sensor responds at room temperature non-linearly to a staircase sequence of ammonia from 1 ppb to 100 ppb. The rise and fall time of the nanowire sensor was found to be 10 s and 9 s, respectively. While the immobilization of VO nanowires increased the electrochemical surface area, the defect rich and ionic nature of the VO surface (V 2+ O 2− ) facilitated the chemical interaction and adsorption of polar ammonia molecules as evident in the room temperature response of the VO@Pt amperometric electrochemical sensor. The availability of metal centered d-electrons and the semiconductor nature of vanadium monoxide lowered the interfacial resistance of the nanowire-modified sensor enabling the lower detection limit of ammonia. The sensor seems to respond to CH 4 , H 2 S and C 3 H 6 as well although the NH 3 response is nearly six-fold compared to these common interfering compounds. The results pave the way for a low-cost alternative paper-based sensor to monitor ammonia emissions primarily from confined animal feeding operations (CAFOs).