In situ enrichment amplification strategy enabling highly sensitive formaldehyde gas sensor

Rapid detection of hazardous trace gas is critical to protect humans from health threats. The current gas sensors, however, suffer from insufficient sensitivity and selectivity, which limits their use in the application of real-time monitoring for low concentration gas. Herein, a versatile “in situ enrichment amplification” (IEA) strategy is proposed, aiming to integrate the in situ formed adsorption-functional material for target gas enrichment and the backbone sensor-functional material for gas response. The IEA-based gas sensors exhibit high sensitivity and selectivity toward the detection of HCHO gas. The calculated detection limit of the IEA sensor to HCHO gas is 63 ppb, much lower than that of the conventional HCHO sensor (183 ppb). Furthermore, a wireless cloud HCHO detection system is developed to achieve sustainable remote monitoring of the HCHO gas. Application of this IEA strategy to other metal oxide sensing materials generates similarly successful results.