Spin-state Conversion by Asymmetrical Orbital Hybridization in Ni-doped Co 3 O 4 to Boost Singlet Oxygen Generation for Microbial Disinfection.

Singlet oxygen ( 1 O 2 ) plays a significant role in environmental and biomedical disinfection fields. Electrocatalytic processes hold great potential for 1 O 2 generation, but remain challenging. Herein, a facile Ni doping converted spin-state transition approach is reported for boosting 1 O 2 production. Magnetic analysis and theoretical calculations reveal that Ni occupied at the octahedral site of Co 3 O 4 can effectively induce a low-to-high spin-state transition. The high-spin Ni-Co 3 O 4 generate appropriate binding strength and enhance electron transfer between the Co centers with oxygen intermediates, thereby improving the catalytic activity of Ni-Co 3 O 4 for effective generating 1 O 2 . In neutral conditions, 1×10 6  CFU mL -1 Gram-negative ESBL-producing Escherichia coli (E. coli) could be inactivated by Ni-Co 3 O 4 system within 5 min. Further antibacterial mechanisms indicate that 1 O 2 can lead to cell membrane damage and DNA degradation so as to irreversible cell death. Additionally, the developed Ni-Co 3 O 4 system can effectively inactivate bacteria from wastewater and bioaerosols. This work provides an effective strategy for designing high-spin electrocatalysis to boost 1 O 2 generation for disinfection process.