Efficient ozone decomposition by amorphous Mn–Ni bimetallic catalysts under an entire humidity environment.

Mn–Ni bimetallic catalysts with different Mn/Ni molar ratios were synthesized by means of a facile hydrothermal reaction and applied for the removal of ozone. The physicochemical properties of prepared samples were systematically characterized, confirming that Ni was incorporated into MnO x lattice to form the amorphous Mn–Ni solid solution. Abundant grain boundaries in amorphous Mn–Ni solid solution facilitated the formation of a large number of oxygen vacancies. Synergistic effects of Mn and Ni improved low-temperature reducibility and lattice oxygen mobility on Mn1Ni1 (molar ratio of Mn²⁺: Ni²⁺ = 1:1). In situ diffuse reflectance infrared Fourier transform spectra (in-situ DRIFTS) analyses displayed that the introduction of Ni enhanced the hydrophobicity of Mn1Ni1 and avoided the enrichment of water molecules on the catalyst surface, but also promoted the conversion of adsorbed water into surface hydroxyl groups to participate in the ozone decomposition. The rapid desorption of intermediate peroxides (O 2 ²⁻) on Mn1Ni1 accelerated the ozone decomposition cycle. Mn1Ni1 exhibited excellent activity and stability for ozone decomposition, keeping 100 % removal of 45 ppm ozone after running for 25 h under high relative humidity of 80 %. [Display omitted] • A novel amorphous Mn−Ni solid solution catalyst was prepared for ozone removal. • The formation of Mn−Ni solid solution generated abundant oxygen vacancies. • Ni enhanced preferential adsorption of ozone on oxygen vacancies. • The synergistic effect of Mn and Ni accelerated the desorption of H 2 O and O 2 ^2–. [ABSTRACT FROM AUTHOR]