Formaldehyde (HCHO) is one of the priority indoor air pollutants emitted from furnishing and building materials, causing profound impacts on human health. In China, the HCHO concentration in 70% of the newly built houses exceeded the safety standards. Catalytic oxidation of HCHO to CO2 by using catalysts is considered as a promising technology for indoor HCHO elimination. α-MnO2 with different exposed facets were synthesized by hydrothermal redox reaction. Figure 1 shows the catalytic performance of HCHO on three α-MnO2 samples with different exposed facets. As shown in Figure 4a, we can find that the catalytic activity exhibits facet-dependent, and the activities followed the order of {310} &gt; {110} &gt; {100}. Under the GHSV of 90 L/gcat.h, the α-MnO2 with the exposed {310} facet could completely transform 100 ppm HCHO into CO2 at as low as 60 °C, which was significantly lower than those of α-MnO2 with the {110} (130 °C) and {100} (150 °C) exposed facets. In addition, the long-term catalytic performance in the real environmental situations was evaluated at an inlet HCHO concentration of 0.44 ppm and a GHSV of 600 L/gcat.h at room temperature. As shown in Figure 1, during the 10 h test periods, the HCHO removal efficiency by α-MnO2-310 remained as high as 86%. We have previously reported a kind of cerium modified birnessite-type MnO2, which exhibited high activity for HCHO removal at low temperature, obtaining ~52% removal efficiency in the same test situations.

Engineering crystal facet of α-Mno2 nanowire for efficient catalytic oxidation of airborne formaldehyde

256th National Meeting (2018)

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