High-performance ethanol gas sensing using surfactant-assisted Bi2MoO6 nanosheets with enhanced sensitivity and selectivity

Abstract

Herein, we report the facile hydrothermal synthesis of Bi₂MoO₆ nanosheets, achieved through the combined use of surfactant-assisted and pH-controlled conditions. A comparative analysis of different types and concentrations of surfactants was conducted to determine the optimal conditions for synthesis. The resulting Bi₂MoO₆ features a mesoporous architecture composed of interconnected nanosheets with an average pore size of approximately 3 nm. Characterization results reveal that this dual approach of surfactant addition and pH control effectively modulates the morphology and optimizes the band gap energy levels of bismuth molybdate materials, significantly enhancing the specific surface area. Notably, Bi₂MoO₆ synthesized with 0.2 mmol of L-Tartaric acid (TA) achieved an exceptionally high response value of 118 to 100 ppm ethanol at an operating temperature of 200 °C, and the sensor demonstrated a practical detection limit as low as 20 ppb (S = 4.13), showcasing its high sensitivity. Additionally, the sensors demonstrated remarkable selectivity for ethanol, outperforming other gases in the concentration range of 100 ppm to 20 ppb. These findings underscore the promise of Bi₂MoO₆ gas sensors prepared via surfactant addition and pH control for the rapid and sensitive detection of low ethanol concentrations at low temperatures. This method could have significant implications for environmental monitoring and industrial safety applications, where the detection of trace levels of ethanol is critical. This Bi₂MoO₆-based sensor, with its combination of high sensitivity, selectivity, and stability, stands out as a valuable tool for advanced gas sensing applications.