Facile tilted sputtering process (TSP) for enhanced H2S gas response over selectively loading Pt nanoparticles on SnO2 thin films

In this paper, we present an enhanced H2S gas sensor based on selectively loading Pt nanocatalyst on the lateral surface of vertically aligned SnO2 thin film with nano-protrusion at a low temperature of 150 degrees C. For this purpose, a facile tilted sputtering process (TSP) to form a new, high surface area hierarchical nanostructure is proposed and envisaged in H2S gas sensor materials at different sensing temperatures. The vertically well aligned semiconductor tin dioxide (SnO2) nanostructured films with average nanorods with diameters ranging from 70-150 nm has been synthesized in which the diameter of the nanorods can be controlled by adjusting the spray pyrolysis deposition time and temperature. The inherent difficulty of detecting H2S gas at temperature lower than 200 degrees C with pure SnO2, were overcome by utilizing Pt/SnO2 thin films, which was synthesized via TSP. The Pt-SnO2 thin films with hierarchical nanostructure enhanced H2S gas response by a factor of 2 and the detection limit as low as 10 ppm compared to the thorough Pt loaded metal oxide at 150 degrees C. The adsorption sites of dissolved oxygen and analyte gas in relation to a TSP induced-Pt layers are elucidated for the enhanced H2S gas response. This work provides a simple, controllable approach that can be extended to the synthesis of other catalyst metal-loaded nanostructures based on metal oxides as gas sensor materials.