Highly Efficient MnO₂/AlOOH Composite Catalyst\nfor Indoor Low-Concentration Formaldehyde Removal at Room Temperature

Abstract

Indoor formaldehyde from substandard\nfurniture and decorative materials\nseriously endangers human health. How to remove effectively indoor\nformaldehyde with low concentration at room temperature is a challenging\nproblem. Using a MnO₂/AlOOH composite by the MnO₂ modification as a catalyst provides an effective approach to solve\nthis challenge. Here, a new type of MnO₂/AlOOH composite\ncatalyst with high ability to remove indoor low-concentration formaldehyde\nwas prepared by redox reaction at room temperature. A MnO₂/AlOOH composite with a homogeneous dispersion of MnO₂ has high specific surface area and a large amount of surface hydroxyl\n(−OH) which plays a major role in the adsorption of formaldehyde.\nA partially crystalline structure was observed in the composite, which\ncontains multivalent Mn ions and a large number of vacancy defects.\nThe surface −OH of composite shows strong oxidation activity\nthrough the charge exchange of multivalent Mn ions and vacancy defects.\nThe composite has a higher ability to remove indoor low-concentration\nformaldehyde compared to the birnessite MnO₂ at room temperature.\nThis study proposes a new idea for the improvement of catalytic performance\nin the structure and composition of the catalyst.