Low-Temperature Oxidation Removal of Formaldehyde Catalyzed by Mn-Containing Mixed-Oxide-Supported Bismuth Oxychloride in Air

Abstract

The Mn-containing mixed-oxide-supported bismuth oxychloride (BiOCl) catalysts were prepared by calcining their corresponding parent hydrotalcite supported BiOCl. The crystal structure of BiOCl was found to be intact during calcination, while significant differences appeared in the chemical state of Mn and the redox capacities of the catalysts before and after calcination. Compared to the hydrotalcite-supported catalysts, the mixed-oxide-supported BiOCl showed much higher catalytic performance in the oxidation removal of formaldehyde due to the synergetic catalysis of more surface oxygen vacancies and higher surface basicity. The complete removal of formaldehyde could be achieved at 70 °C, and the removal efficiency was maintained more than 90% for 21 h. A possible reaction mechanism was also proposed.