An Ultrasensitive Room-Temperature H₂S Gas Sensor Based on 3D Assembly of Cu₂O Decorated WS₂ Nanomaterial

Abstract

Herein, we report for the first time on the fabrication of a hybrid material consisting of Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O nanoparticles-decorated multilayered tungsten disulfide nanostructures and demonstrate their remarkable gas sensing characteristics towards hydrogen sulfide gas. In the first step, a continuous film of WS2 was deposited directly on commercial alumina substrate by adopting a facile route combining aerosol-assisted chemical vapor deposition with H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> free atmospheric pressure CVD technique. For functionalization an additional step of synthesis was added where copper oxide nanoparticles were grown and deposited directly over as-grown tungsten disulfide at low temperature (i.e., 150 °C) using a simple and cost-effective technique. The morphological, structural and chemical characteristics were investigated using FESEM, TEM, and EDX spectroscopy. The gas-sensing studies performed shows that this hybrid nanomaterial has excellent sensitivity towards hydrogen sulfide (11-times increase in response compared to that of pristine WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensor) at moderate temperature (150 °C). Additionally, functionalization of pristine WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensor with Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O nanoparticles further enhances the gas sensing performance towards the targeted gas even at room temperature (13-times increase in response compared with that of pristine WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensor). Moreover, results obtained from humidity cross-sensitivity of Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O-WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensor indicates superior gas sensing response (with a negligible decrease in response) as compared to pristine WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensor, when ambient humidity is increased to 50%, which is rarely found in metal oxide-based sensors. This study could add a significant research value in the gas sensor domain.