Ag-promoted Cr/MnO catalyst for catalytic oxidation of low-concentration formaldehyde at room temperature.

As one of the significant pollutants in indoor air, formaldehyde (HCHO) has attracted increasing attention due to its negative effects on human health. Thus, to reduce formaldehyde pollution, herein, an Ag-promoted Cr/MnO catalyst (Ag/Cr/MnO) was obtained a hydrothermal-calcination method, which was employed for the catalytic oxidation of low-concentration indoor HCHO (∼1 ppm) at room temperature. The Ag/Cr/MnO catalyst eliminated approximately 98.62% HCHO within 14 h and maintained a high removal efficiency continuously under the dynamic test conditions. Furthermore, the catalyst exhibited good recycling stability and outstanding activity in a humid environment. Different characterization techniques were utilized to determine the physicochemical properties that contribute to improving the catalytic performance. The Ag substance contained metallic Ag (Ag) as the main component and some AgO, and the Ag particles provided ample active sites for the catalytic oxidation of HCHO. Besides, the incorporation of Ag increased the reducibility of the catalyst and the content of Mn, Cr and oxygen vacancies. The abundant active sites, high reducibility, rich Mn, Cr, oxygen vacancies, and surface lattice oxygen species, and the powerful interaction between Cr/MnO and Ag were the reasons for the splendid catalytic capability for HCHO by the Ag/Cr/MnO catalyst. In conclusion, the Ag/Cr/MnO catalyst can be a promising catalyst to degrade HCHO with practical application significance.