Research on the elimination of low-concentration formaldehyde by Ag loaded onto Mn/CeO₂ catalyst at room temperature

Formaldehyde (HCHO) is one of the major air pollutants, and its effective removal at room temperature has proven to be a great challenge. In this study, an Ag/Mn/CeO₂ catalyst for the catalytic oxidation of low-concentration HCHO at room temperature was prepared by a hydrothermal-calcination method. The removal performance of the Ag/Mn/CeO₂ catalyst for HCHO was systematically studied, and its surface chemical properties and microstructure were analyzed. The incorporation of Ag did not change the mesoporous structure of the Mn/CeO₂ catalyst but reduced the pore size and specific surface area. The Ag species included metallic Ag as the main component and part of Ag⁺. The well-dispersed Ag species on the catalyst provided sufficient active sites for the catalytic oxidation of HCHO. The more the Ag active sites, the more the lattice defects and oxygen vacancies generated from the interaction of Ag with Mn/CeO₂. Precisely because of this, the Ag/Mn/CeO₂ catalyst exhibited high catalytic activity for HCHO at room temperature with a removal efficiency of 96.76% within 22 h, which is 22.91% higher than that of the Mn/CeO₂ catalyst. Moreover, the Ag/Mn/CeO₂ catalyst showed good cycling stability and the removal efficiency reached 85.77% after five cycles. Therefore, the as-prepared catalyst is an effective and sustainable material that can be used to remove HCHO from actual indoor polluted air. This paper provides ideas for the research and development of efficient catalysts.