Surface Enhancement Effects of Tiny SnO₂ Nanoparticle Modification on α-Fe₂O₃ for Room-Temperature NH₃ Sensing

Abstract

The development of a gas sensor capable of detecting ammonia with high selectivity and rapid response at room temperature has consistently posed a formidable challenge. To address this issue, the present study utilized a one-step solvothermal method to co-assemble α-Fe 2 O 3 and SnO 2 by evenly covering SnO 2 nanoparticles on the surface of α-Fe 2 O 3 . By controlling the morphology and Fe/Sn mole ratio of the composite, the as-prepared sample exhibits high-performance detection of NH 3 . At room temperature conditions, a gas sensor composed of α-Fe 2 O 3 @3%SnO 2 demonstrates a rapid response time of 14 s and a notable sensitivity of 83.9% when detecting 100 ppm ammonia. Experiments and density functional theory (DFT) calculations suggest that the adsorption capacity of α-Fe 2 O 3 to ammonia is enhanced by the surface effect provided by SnO 2 . Meanwhile, the existence of SnO 2 tailors the pore structure and effective surface area of α-Fe 2 O 3 , creating multiple channels for the diffusion and adsorption of ammonia molecules. Additionally, an N−N heterostructure is formed between α-Fe 2 O 3 and SnO 2 , which enhances the potential energy barrier and improves the ammonia sensing performance. Demonstration experiments have proved that the sensor shows significant advantages over commercial sensors in the process of ammonia detection in agricultural facilities. This work provides new insights into the perspectives on ammonia detection at room temperature.

Theoretical Validation of Non-Noble Cu Sites Integrated on SnO2 Nanoflowers for Enhanced Gas Sensing of Ethanethiol at Room Temperature

“…Moreover, it is worth noting that gas sensors for the detection of EtSH are currently quite limited, potentially due to its lower gas-sensing response and the increased risks associated with high-temperature conditions. As a result, there is a critical need to develop gas sensors that operate at room temperature with enhanced sensitivity, especially for detecting flammable and hazardous gases such as EtSH. − However, the most urgent issue with the existing room-temperature gas sensor lies in the imperative to develop high-performance sensing materials, facilitating efficacious identification and detection of the target gas.…”