Fabrication of a Micro-Electromechanical System-Based Acetone Gas Sensor Using CeO₂ Nanodot-Decorated WO₃ Nanowires

Abstract

Preparation of reliable, stable, and highly responsive gassensing devices for the detection of acetone has been considered to be a key issue for the development of accurate disease diagnosis systems via exhaled breath. In this paper, novel CeO 2 nanodot-decorated WO 3 nanowires are successfully synthesized through a sequential hydrothermal and thermolysis process. Such CeO 2 nanodot-decorated WO 3 nanowires exhibited a remarkable enhancement in acetone-sensing performance based on a miniaturized micro-electromechanical system device, which affords high response (S = 1.30−500 ppb, 1.62−2.5 ppm), low detection limit (500 ppb), and superior selectivity toward acetone. The improved performance of the acetone sensor is likely to be originated from the fast carrier transportation of WO 3 nanowires, the formation of WO 3 −CeO 2 heterojunctions, and the existence of large amounts of oxygen vacancies in CeO 2 . The improved reaction thermodynamics and sensing mechanisms have also been revealed by the specific band alignment and X-ray photoelectron spectroscopy analysis.

Ultrasensitive and low detection limit of acetone gas sensor based on ZnO/SnO2 thick films

“…At a lower working temperature, the insufficient thermal energy is not enough to overcome the activation energy of interface reaction, resulting in a very small response values. [14][15][16][17] With the increase of working temperature, the responses of the sensors reach the maximum values, because there is enough thermal energy to overcome the higher barrier. When temperature exceeds the optimum working temperature, the adsorbed gas molecules may escape from the surface, resulting the gas responses decrease.…”

Recent advances in energy-saving chemiresistive gas sensors: A review

“…MOS-decorated gas sensors also have been used in MEMS configurations. For instance, Yuan et al reported a MEMS-based acetone sensor made from CeO 2 nanodots decorated on WO 3 NWs, prepared through a hydrothermal and subsequent thermal decomposition [ 129 ]. The sensor exhibited a response (R a /R g ) of 1.30 to 500 ppb acetone with good stability, which indicates that this sensor can be used to diagnose diabetes via breath analyses.…”

Modulating Ni/Ce Ratio in NiyCe100−yOx Electrocatalysts for Enhanced Water Oxidation

“…The polarization curves were collected through linear sweep voltammetry (LSV), and the scan rate was 10 mV/s. Controlled-current water electrolysis was performed using a chronopotentiometric technique [16]. The solution resistance Rs (~2 Ω), determined using the electrochemical impedance spectroscopy (EIS) technique [16], was used to correct the iR drop across the solution.…”

“…Controlled-current water electrolysis was performed using a chronopotentiometric technique [16]. The solution resistance Rs (~2 Ω), determined using the electrochemical impedance spectroscopy (EIS) technique [16], was used to correct the iR drop across the solution. Unless otherwise stated, all given potentials are vs. RHE and corrected for the iR drop across the electrolyte.…”

“…The specific activity of the Co3O4 nanosheets with oxygen vacancies was 10 times higher than that of the pristine Co3O4. Ceria is a nonstoichiometric material and the oxygen vacancies are easily formed due to the shift between Ce 3+ and Ce 4+ [13][14][15][16][17]. The oxygen vacancies in Ce-containing catalysts such as CeO2/Co3O4 accelerated the electron transfer, resulting in good OER activity [9].…”