Formaldehyde (HCHO), as a primary pollutant in indoor air, has attracted much attention due to its wide sources, long release period and carcinogenic characteristics. Due to its high catalytic activity at low temperature, low toxicity and low-cost, MnO₂ has been employed in catalytic decomposition of HCHO. Herein, the research progress of catalytic decomposition of HCHO by MnO₂ is reviewed from three aspects: MnO₂ supported noble metals, structural regulation of MnO₂, and composite of MnO₂ with other non-noble metal materials. The effects of structural regulation strategies such as supported noble metals, crystal structure and morphology, interlayer/tunnel cations, surface defects, atom doping and other composite materials on the catalytic performance of MnO₂ for HCHO were discussed. Moreover, the differences of HCHO catalytic decomposition mechanism between noble metal and non-noble metal are compared. Ultimately, the problems and challenges faced by the purification of the indoor HCHO are analyzed and the research directions for the decomposition of HCHO by MnO₂ are also proposed.

Contents:

1 Introduction

2 Structure and properties of manganese dioxides

3 Research progress on catalytic decomposition of HCHO by manganese dioxides

3.1 Catalytic decomposition of HCHO by manganese dioxide supported noble metals

3.2 Catalytic decomposition of HCHO by non⁃noble metal manganese dioxides

4 Mechanism of catalytic decomposition

4.1 Catalytic decomposition mechanism of HCHO by noble metals

4.2 Catalytic decomposition mechanism of HCHO by manganese dioxides

5 Conclusion and outlook