Micro-cantilever sensors for monitoring carbon monoxide concentration in fuel cells

Abstract

High concentration of carbon monoxide (CO) in the gas mixture entering the fuel cell can cause fuel cell poisoning, which can significantly reduce the life expectancy of the cell. To overcome this problem, we propose a new methodology based on the use of micro-cantilevers to detect minute concentrations of CO in a gas mixture. For this purpose, micro-cantilevers are coated with Copper Y (CuY) zeolite and utilized to selectively adsorb CO on their surface. It is shown that the adsorption of CO yields a measurable shift in the natural frequency of the micro-cantilevers, which can be directly correlated with the concentration of CO in the gas mixture. It is determined that the maximum adsorption capacity of the sensor occurs at 40 °C using CuY zeolite with 10 wt% Cu content. Furthermore, the shift in the natural frequency of the sensor is observed to increase as the thickness of the zeolite layer is increased up to a threshold value corresponding to about a quarter of the thickness of the micro-cantilever. At this point, a clearly measurable shift of about 275 Hz in the natural frequency of the micro-cantilevers is observed. While the maximum frequency shift occurs using a relatively thick zeolite layer, it is observed that, for the range of thicknesses considered, the maximum frequency shift per unit weight of CO adsorbed (sensitivity) decreases as the thickness of the zeolite layer is increased. The methodology proposed in this paper could pave the way towards the development of a portable and self-contained unit to monitor the concentration of CO in a mixture of gases.

Three-dimensional nonlinear extreme vibrations of cantilevers based on a geometrically exact model

“…Beam, plate, and shell structures can be found in various engineering systems [1,2,3,4,5,6,7,8]. As a sub-class of these structures, cantilevers are present in numerous engineering applications ranging from macro [9,10,2] to nano scale, such as micro/nano-electromechanical systems, micro gyroscopes, vibration energy harvesters, and scanning probe microscopy [11,12,13,14,15,16].…”

Comprehensive Review of Fuel-Cell-Type Sensors for Gas Detection

“…Mojtahedi et al found that the amount of catalyst loading, the electrode microstructure, the kind of catalyst, and the type of electrolyte are the effective vital parameters on the performance of any electrochemical sensors. The outcome of research works indicates that by increasing the temperature, − response time − and sensitivity of measurement − are reduced and improved, respectively.…”

Experimentally validated geometrically exact model for extreme nonlinear motions of cantilevers

“…Cantilevered structural elements are present in a wide range of mechanical systems and civil structures [6,9,17,19,33,56]. They can be found in numerous engineering applications including, but not limited to, vibration energy harvesters, micro-gyroscopes, electromechanical systems, bio-inspired propulsion, and piezoelectric sensors and actuators [1,7,24,31,40,43,55,59]. The key feature that differentiates cantilevers from other structures/elements that are supported from more than one side is their capability of undergo-ing large-amplitude deflections/oscillations.…”

“…Inserting Eqs. (3), ( 5), (7), and (8) into the extended Hamilton's principle one can obtain the geometrically exact equation governing the rotational motion of the centreline of the cantilevered beam as…”