Density functional theory calculations on 2H-MoS2 monolayer for HCHO degradation: Piezoelectric-photocatalytic synergy

Formaldehyde (HCHO) is a common indoor gaseous pollutant, and long-term exposure to it may cause serious damage to the human immune system. Photocatalytic degradation of HCHO is a promising technique. However, most photocatalysts have the disadvantage of rapid recombination of photo-generated electron-hole pairs. In this work, the recombination of photogenerated electron holes was proposed to inhibit through the piezoelectric effect. A two-dimensional (2D) piezoelectric material, 2H-MoS2, was selected to investigate the catalytic performance for HCHO degradation by the synergy of the piezoelectric and photocatalysis properties. The results show that the piezoelectric effect can induce the polarization in 2H-MoS2 and inhibit the recombination of photogenerated electron-hole pairs, thus improving the photogeneration of hydroxyl radicals for HCHO degradation. Therefore, the piezoelectric-photo-catalysis synergistic effect based on density functional theory (DFT) calculation was proposed to elucidate the HCHO degradation performance. This work could provide important guidance for the development of effective catalysts for HCHO degradation and the application of 2D piezoelectric materials.