Spin-state Conversion by Asymmetrical Orbital Hybridization in Ni-doped Co₃ O₄ to Boost Singlet Oxygen Generation for...

Singlet oxygen (¹ O₂ ) plays a significant role in environmental and biomedical disinfection fields. Electrocatalytic processes hold great potential for ¹ O₂ generation, but remain challenging. Herein, a facile Ni doping converted spin-state transition approach is reported for boosting ¹ O₂ production. Magnetic analysis and theoretical calculations reveal that Ni occupied at the octahedral site of Co₃ O₄ can effectively induce a low-to-high spin-state transition. The high-spin Ni-Co₃ O₄ generate appropriate binding strength and enhance electron transfer between the Co centers with oxygen intermediates, thereby improving the catalytic activity of Ni-Co₃ O₄ for effective generating ¹ O₂ . In neutral conditions, 1×10⁶  CFU mL^-1 Gram-negative ESBL-producing Escherichia coli (E. coli) could be inactivated by Ni-Co₃ O₄ system within 5 min. Further antibacterial mechanisms indicate that ¹ O₂ can lead to cell membrane damage and DNA degradation so as to irreversible cell death. Additionally, the developed Ni-Co₃ O₄ system can effectively inactivate bacteria from wastewater and bioaerosols. This work provides an effective strategy for designing high-spin electrocatalysis to boost ¹ O₂ generation for disinfection process.