Interface engineering of a 3D carbon nanofiber/iron oxide scaffold for room-temperature ethanol sensing

Ethanol is one of the most widely consumed chemicals and has high volatility. Long-term exposure to ethanol can cause irritation and damage to human organs and even lead to cancer. Therefore, reliable, low-cost and low-power ethanol gas sensors are urgently needed. However, due to the high barrier associated with the reaction between adsorbed oxygen and ethanol gas, current commonly used chemiresistive sensors are difficult to detect low concentration of ethanol gas at room temperature. Herein, we developed a 3D composite scaffold sensor, i.e. iron oxide nanoparticles decorated carbon nanofiber scaffolds (CNFs) from both the inside and outside (named Fe 2 O 3 @FCNFs) through interface engineering. The Fe 2 O 3 @FCNFs composite scaffold exhibited a 6-fold increase in specific surface area as compared to that of the FCNFs, and its carrier concentration of was one order higher than that of its counterpart. Therefore, the typical Fe 2 O 3 @FCNFs sensor exhibited an unanticipated good response to ethanol gas at room temperature, including high sensitivity (-6.268 % toward 100 ppm) and low limit of detection (10 ppm). This study provides an effective solution for preparing room-temperature chemiresistive ethanol gas sensors, which can be extended to other gas detection by tuning the semiconductor sensitive materials.