Atomically Dispersed Y or La on Birnessite-Type MnO2 for the Catalytic Decomposition of Low-Concentration Toluene at Room Temperature

Room-temperature catalytic decomposition of low-concentration volatile organic compounds (VOCs) in indoor air is an exciting dream to solve their pollution. Herein, two kinds of rare-earth elements (Y and La) were separately doped into birnessite-type MnO₂ nanosheets in the form of single atoms by the hydrothermal method. As-synthesized La/MnO₂ achieved 100% removal of 10 ppm toluene at 40 °C under the gas hourly space velocity of 60 L g^-1 h^-1, which was even somewhat better than the single Pt atom-doped MnO₂. In addition, La/MnO₂ showed the good durability at room temperature for 0.5 ppm toluene removal under the GHSV of 300 L g^-1 h^-1 and could be effectively regenerated at 105 °C. GC/FID, online-MS and TD-GC/MS analysis demonstrated that only ignorable trace benzene (∼3.4 ppb, < one thousandth of inlet toluene) was generated in the gas phase during catalytic decomposition of 10 ppm toluene at room temperature. This research sheds light on the development of low cost and high activity catalysts for low-concentration VOC oxidation at room temperature.