Stepwise emergence of CO gas sensing response and selectivity on SnO using C supports and PtO decoration.

Room temperature gas sensing is crucial for practical devices used in indoor environments. Among various materials, metal oxides are commonly used for gas sensing, but their strong insulating properties limit their effectiveness at room temperature. To address this issue, many studies have explored diverse methods such as nanoparticle decoration or conductive support, etc. Here, we report the emergence of gas-sensing functionality at room temperature with improved CO gas selectivity on SnO nanoparticles through sequential steps by using amorphous carbon (a-C) support and PtO decoration. The SnO decorated on amorphous carbon shows enhanced gas adsorption compared to inactive gas sensing on SnO decorated carbon support. The higher V site of SnO on a-C induces gas adsorption sites, which are related to the higher sp bonding caused by the large density of C defects. The ambiguous gas selectivity of SnO/a-C is tailored by PtO decoration, which exhibits six values of sensing responses (R/R or R/R) under CO gas at room temperature with higher selectivity. Compared to PtO/a-C, which shows no response, the enhanced CO gas sensing functionality is attributed to the CO adsorption site on PtO-decorated SnO particles. This report not only demonstrates the applicability of CO gas sensing at room temperature but also suggests a strategy for using SnO and carbon compositions in gas sensing devices.