Highly Dispersed Pt-Incorporated Mesoporous Fe₂O₃ for Low-Level Sensing of Formaldehyde Gas

Highly dispersed Pt-incorporated mesoporous Fe₂O₃ (Pt/m-Fe₂O₃) of 4 μm size is prepared through a simple hydrothermal reaction and thermal decomposition procedures. Furthermore, the formaldehyde gas-sensing properties of Pt/m-Fe₂O₃ are investigated. Compared with our previous mesoporous Fe₂O₃-based gas sensors, a gas sensor based on 0.2% Pt/m-Fe₂O₃ shows improved gas response by over 90% in detecting low-level formaldehyde gas at 50 ppb concentration, an enhanced selectivity of formaldehyde gas, and a lower degradation of sensing performance in high-humidity environments. Additionally, the gas sensor exhibits similar properties as the previous sensor, such as operating temperature (275 °C) and long-term stability. The enhancement in formaldehyde gas-sensing performance is attributed to the attractive catalytic chemical sensitization of highly dispersed Pt nanoparticles in the mesoporous Fe₂O₃ microcube architecture.