An ultrasensitive room-temperature H2S gas sensor based on 3D assembly of Cu2O decorated WS2 nanomaterials

Herein, we report for the first time on the fabrication of a hybrid material consisting of Cu2O 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 H2 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 WS2 sensor) at moderate temperature (150 °C). Additionally, functionalization of pristine WS2 sensor with Cu2O 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 WS2 sensor). Moreover, results obtained from humidity cross-sensitivity of Cu2O-WS2 sensor indicates superior gas sensing response (with a negligible decrease in response) as compared to pristine WS2 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.