Narrow Results

Formaldehyde is regarded as the major indoor air pollutant. Because of harmful effect on human health, its emission abatement is of significant practical interest. We report here excellent low-temperature catalytic performances of mesoporous MnO_x-CeO₂ catalysts in the process of formaldehyde oxidation. These MnO_x-CeO₂ catalysts were synthesized by a "nanocasting" method using SBA-15 as hard template. TEM images showed that the as-fabricated MnO_x-CeO₂ composites possess well-ordered mesoporous architectures. Results of catalytic tests revealed that mesoporous MnO_x-CeO₂ nanocomposites have excellent low-temperature catalytic activity for formaldehyde oxidation, the temperature for 100% formaldehyde conversion can be as low as 65°C over these noble-metal-free mesoporous catalysts. The excellent catalytic performance is attributed to their ordered mesoporous structures that expose abundant active sites to formaldehyde molecules.

A cataluminescence (CTL) based method for simultaneously identifying and determining formaldehyde (HCHO) and sulfur dioxide (SO₂) in air was proposed. The experimental conditions meeting the algebraic sum rule of the CTL intensities of HCHO and SO2 were sought. They are two analysis wavelengths of 460 nm and 580 nm, the surface temperature of sensing materials of 280°C and the flow rate of air of 130 mL/min. The limits of detection of this method were 0.08 mg/m³ for HCHO and 0.6 mg/m³ for SO₂. Common coexistence matters, such as acetaldehyde, ammonia, benzene, ethanol, hydrogen sulfide and carbon dioxide, did not disturb the determination.