Unravelling the Cd Immobilisation Mechanism of NiN 3 ‐Embedded Biochar via First‐principles Calculations

Cadmium (Cd) pollution in paddy fields is a substantial threat to rice growth and food security. Although biochar is regarded as an ideal soil remediation agent, its practical application is hindered by its limited Cd‐anchoring properties. Herein, we propose a NiN 3 embedding strategy to reinforce the biochar's Cd immobilisation ability via first‐principles calculations. The theoretical simulation findings indicate that the NiN 3 ‐embedded strategy can enhance the binding energy of pristine biochar towards CdCl 2 from 0.05 to 1.58 eV. Moreover, electronic structure analyses elucidated that NiN@G possesses excellent physicochemical interactions when bound with CdCl 2 because the embedding of Ni and N strengthens electron exchange, which results in the formation of atomic orbital hybridisation among multiple elements. This study underscores the potential mechanism of single‐atom catalysts embedded in biochar and lays the foundation for the rational design of materials for heavy metal immobilisation.