A theoretical study of the effect and mechanism of FeN3-doped biochar for greenhouse gas mitigation.

Paddy fields are a major emission source of greenhouse gases (GHGs) [for instance, methane (CH₄), nitrous oxide (N₂O), and carbon dioxide (CO₂)] among agricultural fields. Biochar has been deemed a potential candidate for the reduction of GHGs in paddy fields. However, there is no consistent conclusion that biochar can simultaneously reduce emissions of CH₄, N₂O, and CO₂. Herein, we proposed the FeN₃-doped biochar (FG) as an excellent material for GHGs restriction in paddy fields via the first-principles calculation. The computation results indicated that the FG exhibited satisfactory adsorption ability for CH₄, CO₂, and N₂O, which improved the adsorption energies to −1.37 , −1.54, and −2.91 eV, respectively. Moreover, the density of state (DOS) analyses revealed that the factor responsible for FeN₃-doped biochar to exhibit excellent adsorption ability was the occurrence of drastic energy up- or down-shift of the electron for Fe d, C p, O p, or N p orbital upon adsorption of CH₄, CO₂, or N₂O. Our study suggested an advanced modified biochar material for reducing the GHGs emissions in paddy fields, in addition to exploring the adsorption properties and mechanisms of FeN₃-doped biochar for GHGs mitigation, which provided a strategy to explore biochar modification and efficient emission reduction materials. Article highlights: • FeN₃-doped biochar was first proposed for GHGs mitigation in paddy fields. • FeN₃-doped biochar exhibited excellent GHGs adsorption ability. • FeN₃-doped biochar improved physico-chemical adsorption ability for GHGs. [ABSTRACT FROM AUTHOR]