Volatile organic compounds (VOCs) are important precursors for the formation of secondary pollutants, such as fine particulate matter (PM) and ozone (O₃), which will lead to severe atmospheric environmental problems to restrict the sustainable development of the social economy. Catalytic oxidation is a safe, eco-friendly, and simple method for eliminating VOCs, which can be converted into CO₂ and H₂O without the generation of other harmful substances. The fabrication and development of catalysts are very crucial to enhance the catalytic oxidation efficiency of the removal of VOCs. The noble metal catalyst is one of the commonly used catalysts for the catalytic oxidation of VOCs because of the high reaction activity, good stability, poisoning-resistant ability, and easy regeneration. In this review, the research progress of noble metal (Pt, Pd, Au, Ag, and Ir) catalysts for the removal of VOCs in recent years was summarized with the discussion of the influence factors in the preparation process on the catalytic performance. The reaction mechanisms of the removal of VOCs over the corresponding noble metal catalysts were also briefly discussed.

Polyurethanes (PUs) have been versatilely applied in various fields because of their preferable properties with both elasticity and hardness. Due to the thermodynamic incompatibility of hard segments and soft segments, the PUs generally have the microphase-separated structures, which could dramatically affect their chemical and mechanical properties. In this review, the characterization methods of microphase-separated structures in PU polymers, such as fourier transformed infrared spectroscopy (FTIR), atomic force microscopy (AFM), differential scanning calorimetry (DSC), and small-angle X-ray scattering (SAXS) are summarized and illustrated. The relationship between microphase-separated structures and PU properties is also discussed. This review will lay the theoretical foundation for the improvement on the application performance of PUs.

Many achievements have been made on the research of composite polyurethane foams to improve their structure and mechanical properties, and the composite foams have been widely utilized in building insulation and furniture. In this work, rigid polyurethane foams (RPUFs) with the addition of different fillers (nano-SiO₂, peanut shell, pine bark) were prepared through the one-step method. The effects of inorganic nano-SiO₂ and organic biomass on foam properties were evaluated by means of physical and chemical characterization. The characterization results indicate that the compressive strength values of prepared foams could fully meet the specification requirement for the building insulation materials. The inorganic and organic fillers have no effect on the hydrogen bonding states in composite RPUFs. Furthermore, compared to the biomass fillers, the addition of nano-SiO₂ greatly influenced the final residual content of the fabricated foam. All composite foams exhibit closed-cell structure with smaller cell size in comparison with the parent foam. The prepared composite foams have the potential for utilization in building insulation.