Regulating the charge density of Cu(I) single sites enriched on the surface of N3c Vacancies-engineered g-C3N4 for efficient Fenton-like reactions

The construction of highly accessible copper active sites with enhanced charge density is essential for the performance of Cu-based Fenton catalysts. Herein, we report the preparation of a catalyst comprising Cu(I) atoms anchored on the surface of N3c vacancies-engineered g-C3N4 (Cu/Nv-CN) and its enhanced Fenton-like performance. The surface-enrichment of single Cu(I) atoms maximizes the exposure of active sites and reduces the mass transfer limitation for short-lived hydroxyl radicals. The N3c vacancies, meanwhile, facilitate electron donation from N2c to Cu sites, greatly increasing the number of single Cu(I) sites. These two strategies synergistically enhance the hydroxyl radical production rate in the Fenton-like process and endow Cu/Nv-CN with not only excellent performance in degrading various contaminants (such as phenolic compounds, endocrine disruptors, antibiotics, and dyes), both in purified and real water samples matrixes, but also superior bactericidal properties for Escherichia coli. Compared to bulk Cu-doped g-C3N4 without N3c vacancies (CO-Cu/CN), Cu/Nv-CN shows a more than 14-fold increase in phenol degradation and an enhancement of approximately 4 log10 CFU/mL in bacterial inactivation. Our strategy of increasing the number of Cu(I) single atoms through surface enrichment and enhanced electron donation opens up a new route for the design of efficient Fenton-like catalysts for environmental remediation.