Effect of calcination temperature on the structure and formaldehyde removal performance at room temperature of Cr/MnO2 catalysts

In this paper, Cr/MnO 2 catalysts were prepared by hydrothermal–calcination method and applied to the catalytic oxidation of formaldehyde (HCHO) at room temperature. The effects of calcination temperature on the physicochemical properties of Cr/MnO 2 catalysts were investigated by means of N 2 adsorption–desorption, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. Based on this, the formaldehyde removal mechanism of Cr/MnO 2 catalysts was proposed. The results showed that the specific surface area, O II /O I , Mn 4+ /Mn 3+ and Cr 6+ /Cr 3+ ratios of the Cr/MnO 2 catalysts varied with the calcination temperature. The Cr/MnO 2 catalyst calcined at 400 °C (CM400) has higher specific surface area (64.6 m 2 /g) and oxygen vacancy content, so it exhibits better formaldehyde removal performance, which could reach 92.1% within 22 h. It is concluded that the high specific surface area, abundant oxygen vacancy content, rich Mn 4+ and Cr 6+ species are primary reasons for the excellent formaldehyde removal performance of CM400 sample. The Cr/MnO 2 catalysts reveal great application potential in indoor formaldehyde degradation, and will be promising industrial formaldehyde degradation catalyst.