Electrochemical Gas Sensor Integrated with Vanadium Monoxide Nanowires for Monitoring Low Concentrations of Ammonia Emission

Abstract

An electrochemical sensor for the detection of extremely low concentration of ammonia (1 part per billion, ppb) was fabricated by integrating vanadium monoxide (VOx; 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 (V2+O2−) 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 CH4, H2S and C3H6 as well although the NH3 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).

Room‐Temperature High‐Performance Trace Level Acetone Sensor Based on Polypyrrole Nanotubes

“…These lines intersect at a point “P” (5 ppm). This indicates that active sites on the sensor surface get nearly exhausted beyond this concentration of acetone vapour [41–43] …”

Electrically Transduced Gas Sensors Based on Semiconducting Metal Oxide Nanowires

“…Other electrically transduced sensor architectures have also been reported. Several electrochemical sensors based on NWs like tungsten oxide, CuO, ZnO and vanadium monoxide can be found in the literature, showing high selectivity and quantitative analytical information to target gases, pH, humidity, glucose and DNA [27,36,49,[140][141][142][143][144][145][146]. Capacitive-type sensors define the sensitivity using the change in capacitance at a fixed voltage, and they are not generally applied to detecting inorganic gases [147,148].…”

Закономерности Формирования Электропроводящих Свойств Окислов Ряда Магнели

“…В ряду всевозможных окислов металлов окислы ванадия занимают особое место. Прикладная востребованность этих материалов ввиду удобства их практического применения не вызывает сомнений [1]. А их необычность заключается в том, что эти соединения образуют ряд Магнели: VO x , где x меняется от 0.2 (V 5 O) до 2.5 (V 2 O 5 ).…”