Facile preparation of FL-Ti3C2/BiOCl/SnO2 ternary composite for photocatalytic degradation of indoor formaldehyde

Formaldehyde is recognized as a potential human carcinogen by the International Cancer Research Center (IARC). Conventional methods for removing volatile organic compounds (VOCs), such as catalytic combustion, low-temperature plasma method, and condensation recovery method, are not suitable for indoor formaldehyde removal. The ternary composite photocatalysts FL-Ti3C2 (few-layer Ti3C2)/BiOCl/SnO2 (FBS) were prepared and loaded on the melamine sponge in this work. According to the number of soaking times in the FBS solution by the sponge, the sample was named nSFBS. Due to the special composition, suitable energy band structure and large gas–solid reaction interface, the degradation rate of formaldehyde over the sample of 3SFBS under ultraviolet (UV) irradiation was 90.3%, higher than that of single-component FL-Ti3C2, BiOCl, or SnO2. As the number of immersion of the ternary composite photocatalysts increases, the degradation rate for formaldehyde first increased and then decreased. FL-Ti3C2 has super-hydrophilic properties, which makes the composite material SFBS a good affinity for the polar gas formaldehyde. The stability of the ternary composite was also verified, and the degradation rate was only reduced by 14.8% after 5 recycles. The ternary structure extends the lifetime of photogenerated carriers. This work provides new insights that will help to further develop photocatalysts for indoor air purification.Graphic Abstract