Highly Dispersed Pt-Incorporated Mesoporous Fe 2 O 3 for Low-Level Sensing of Formaldehyde Gas.

Highly dispersed Pt-incorporated mesoporous Fe 2 O 3 (Pt/m-Fe 2 O 3 ) of 4 μm size is prepared through a simple hydrothermal reaction and thermal decomposition procedures. Furthermore, the formaldehyde gas-sensing properties of Pt/m-Fe 2 O 3 are investigated. Compared with our previous mesoporous Fe 2 O 3 -based gas sensors, a gas sensor based on 0.2% Pt/m-Fe 2 O 3 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 Fe 2 O 3 microcube architecture.