Photoactivated Pd-Loaded WO3 for Enhanced H-2 S Sensing

In this article, pristine WO3 and Pd-loaded WO3 are synthesized via facile hydrothermal method and integrated with the Internet of Things (IoT)-enabled portable resistance readout circuit for real-time sensing performance measurement of the fabricated sensor toward H2S. A series of characterizations are performed to investigate the crystal structure, surface morphology, active surface area, and elemental composition of the synthesized materials. Pristine WO3 nanoplates show a 9.13 sensing response toward 100-ppm H2S exposure, while loading of 0.25 and 0.5 mol% Pd further improves the response up to 14.37 and 23.45, respectively. However, further loading of Pd (1 mol%) on WO3 nanoplates reduces the sensing response to 15.29. The fabricated 0.5 mol% Pd-loaded WO3 sensor is investigated under thermal and photoenergy excitations. Moreover, the temperature optimization of 0.5 mol% Pd-loaded WO3 exhibits a higher sensing response of 47.8 at 100 degrees C. Furthermore, under visible and ultraviolet (UV) illumination, the 0.5 mol% Pd-loaded WO3 sensor response increases from 47.8 to 57.3 and 63. The fabricated 0.5 mol% Pd-loaded WO3 sensor exhibits remarkable response, shorter response-recovery time, and ultraselectivity toward analyte gas.

Automated summary

In this study, pristine WO3 and Pd-loaded WO3 were synthesized using a simple hydrothermal method and integrated with an IoT-enabled portable resistance readout circuit for real-time sensing of H2S. Various characterizations were performed to investigate the crystal structure, surface morphology, active surface area, and elemental composition of the synthesized materials. The sensor showed improved sensing response towards H2S with the loading of 0.25 and 0.5 mol% Pd, but a reduction in response was observed with further loading of 1 mol% Pd.