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Copper/carbon catalysts under different electron-transfer regimes can evolve both radical and nonradical pathways in peroxide activation. However, the underlying trigger to manipulate the transition in between is unclear. Herein, it is revealed that Cu species in a state of sub-nanometre particles (SNPs, < 1 nm) exhibits an electrophilic nature, which is opposite to its nucleophilic nature at a larger scale (nanoclusters, > 1 nm). This switch between nucleophile/electrophile nature leads to distinct catalytic mechanisms in activating peroxymonosulfate, i.e., nonradical 1O2 surface-bound upon Cu SNPs and unleashed radical •OH induced by Cu nanoclusters. The vacancy defects of biomass-derived carbon can stabilize Cu SNPs via a Cu-V-C configuration, circumventing the contemporary difficulties in coordinating/preserving Metal-N-C bonding. Depth profiling, chemical probes, and charge density difference modeling support the regulable electroactive nature over modulated Cu scales. This featured system is applied for tetracycline degradation, and Cu SNPs demonstrates the highest efficacy with their better peroxymonosulfate confinement in nonradical regime (88.9% removal, nucleophilic activation). Comparatively, severe Cu leaching caused by radical erosion (44.8% removal, electron-donation) is undesirable. Overall, a regulable heterogeneous catalysis is unraveled over carbon-supported Cu sites through scaling modulation and defect engineering. This study illuminates a promising path for customizing biomass-derived Cu-based catalysts to achieve versatile catalysis.

Shuguang Xu,1 Jinjing Tu,1 Liang Zhang,1 Yinv Chen,1 Xiaoqi Dong,1 Xiaohui Chi,2,&ast; Hao Xu2,&ast; 1Department of Pulmonary and Critical Care Medicine, Ningbo Medical Center Lihuili Hospital, Ningbo, People’s Republic of China; 2Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Hao Xu; Xiaohui Chi, Email xuhao930523@163.com; chixiaohui@zju.edu.cnPurpose: Nosocomial infections caused by New Delhi metallo-β-lactamase (NDM)-producing bacteria are prevalent worldwide. However, such diseases caused by NDM-producing Aeromonas caviae had never been reported. Our study aimed to elucidate the genomic characteristics of NDM-1-producing A. caviae isolated from hospital patients.Methods: Bacterial genomic features and possible origins were assessed by whole-genome sequencing (WGS) and phylogenetic analysis. Subsequent investigations include antimicrobial susceptibility testing and multilocus sequence typing (MLST).Results: We identified here two NDM-1-producing A. caviae isolates from bacteremia. Susceptibility testing showed that two isolates were multi-drug resistant and shared a similar resistance profile and were only sensitive to amikacin and trimethoprim/sulfamethoxazole. Both A. caviae isolates carry the carbapenem resistance gene blaNDM-1 and also have antibiotic resistance genes such as β-lactams, AmpC enzymes, macrolides, aminoglycosides, and quinolones. S1-PFGE and Southern blot analysis were negative. Whole-genome sequencing and comparative analysis revealed that these two isolates shared a close relationship.Conclusion: To the best of our knowledge, this work describes the first detection of non-plasmid encoded blaNDM-1 in A. caviae. The A. caviae isolated in this stu