Improved CH₄ Detection Utilizing Pt-Decorated ZnO Nanorods-Coated on a Dynamic Microcantilever Surface

Detecting methane (CH4) at room temperature through adsorption-based sensing poses a challenge due to its inert properties. In this study, we enhance both the sensitivity and selectivity of CH4 detection by decorating ZnO nanorods (ZNRs) with platinum (Pt), forming Pt-decorated ZNRs (PZNRs), which are then coated on a microcantilever surface. The sensor’s response is monitored by measuring the resonance frequency shift, ranging from 3 to 20 Hz, and Q-factor of 194 to 208, as CH4 flows at rates of 10–100 mL/min under room temperature conditions. The introduction of Pt significantly enhances the sensor’s sensitivity to picogram levels, enabling the detection of extremely low concentrations of CH4. To assess the sensor’s selectivity, we compared its response to CH4 with that of carbon monoxide (CO). The results demonstrate that the sensor exhibits a substantially higher response to CH4, with CO detection showing minimal (9–19 times smaller than CH4) or no response. The presence of Pt atoms improves the ability of the PZNR surface to interact with CH4, which is further substantiated by density functional theory (DFT) analyses. These analyses reveal that the PZNRs exhibit greater selectivity toward CH4 than CO, as indicated by the more negative adsorption energy for CH4, suggesting a more stable and favorable adsorption configuration. The combination of high sensitivity, exceptional selectivity, and room temperature operation makes this sensor a highly effective and advantageous solution for CH4 detection, with potential applications in environmental monitoring, industrial safety, and energy sectors.