Preparation of a Pt/TiO2/cotton fiber composite catalyst with low air resistance for efficient formaldehyde oxidation at room temperature†
For the first time, nano TiO2 was coated on the surface of cotton fiber by a dip-coating method, and then Pt nanoparticles (NPs) were deposited onto the surface of the TiO2/cotton fiber (TC) to obtain a Pt/TiO2/cotton fiber composite (PTC) catalyst by a combined method involving the impregnation of the TiO2/cotton fiber with the Pt precursor and NaBH4-reduction. The prepared PTC sample was used for oxidative decomposition of formaldehyde (HCHO) at room temperature and the effect of Pt loading on catalytic performance was investigated. The results show that the PTC catalyst has much lower air resistance than the powder-like sample, which is of great importance for its actual application, and it can efficiently catalyze oxidation of HCHO into CO2 and H2O. The optimum Pt loading was 0.75 wt%. The PTC catalyst also exhibited good catalytic stability in recycling experiments. The TiO2 coating in the PTC catalysts plays an important role in obtaining a high catalytic activity and a good stability. In situ diffuse reflectance infrared Fourier transformation spectroscopy (DRIFTS) results showed that formate, CO and dioxymethylene (DOM) species are the main intermediate species, and a mechanism for HCHO catalytic oxidation over the PTC catalyst was proposed. This work may promote the actual application of high-performance catalysts for indoor air purification and related catalytic processes due to the merits of low air resistance, light mass, flexible properties, good efficiency of the PTC catalyst, and low cost, as well as cotton being an abundant raw material.