Enhanced room-temperature catalytic decomposition of formaldehyde on magnesium-aluminum hydrotalcite/boehmite supported platinum nanoparticles catalyst

Abstract

Magnesium-aluminum hydrotalcite (Mg-Al HT)/boehmite (AlOOH) composite supported Pt catalysts were obtained via one-pot microemulsion synthesis of Mg-Al HT/AlOOH composite and NaBH4-reduction of Pt precursor processes. The catalytic performances of the catalysts were evaluated for formaldehyde (HCHO) removal at room temperature. The performance tests showed that the catalyst obtained by immobilizing Pt nanoparticles (NPs) on Mg-Al HT/AlOOH support with Al/Mg molar ratio equivalent to 9:1 (Pt/Al9Mg1) displayed a superior catalytic activity and stability for HCHO removal. In order to find out the causes of its higher activity, X-ray diffraction, transmission electron microscopy, N2 adsorption/desorption, X-ray photoelectron spectroscopy, temperature programmed desorption of CO2 and reduction of H2 were used to analyze the physicochemical properties of Pt/Al9Mg1 and Pt/AlOOH. The remarkable catalytic performance of Pt/Al9Mg1 is mainly attributed to the relatively larger amount of surface oxygen species, and more reactive oxygen species led by the interaction of Mg-Al HT and AlOOH/Pt, and relatively larger number of weak base sites caused by Mg-Al HT. The formate species are the main reaction intermediate over Pt/Al9Mg1 during HCHO oxidation at room temperature, which could be further oxidized into CO2 and H2O in the presence of O2. This study might shed some light on further improving the catalytic performance of the catalyst for indoor air purification at room temperature.