Hierarchical porous LaFeO₃ nanostructure for efficient trace detection of formaldehyde

Metal oxide based gas sensing is promising to realize the effective detection of formaldehyde from the breathing gas, which is of great significance to lung cancer monitoring in the budding period. Seeking for novel materials with controlled microstructure and surface characteristics, while improving the sensing limit is still a highly desirable challenge. In this work, the hierarchical porous LaFeO₃ is explored for this purpose by using a low-cost, simple and mature method. By tuning the quantity of F108 structuring agent and calcined temperature, the corresponding gas-sensing properties can be adjusted and optimized. The results indicate that the LaFeO₃ with 0.5 g F108 possess the best gas-sensing property with sensing response of 116 toward 50 ppm formaldehyde at 125 °C. Importantly, the trace detection capacity is as low as 50 ppb, which is among the lowest value in the record of formaldehyde detection. Further detailed analysis indicates that the special hierarchical porous structure with high surface area and pore volume should be responsible for the improved sensing performance. These results suggest that construct hierarchical porous structure is a promising method to attain superior gas-sensing properties and LaFeO₃ can be potentially used for accurate, inexpensive, real-time, and painless detection of lung cancer.