Curvature strain engineering enhanced singlet oxygen selectivity: Dual-Function FeN₄ sites for targeted guanine...

Peroxymonosulfate (PMS)-based Fenton-like systems have emerged as a promising technology for extracellular antibiotic resistance gene (eARG) elimination in water remediation, yet the simultaneous realization of low oxidant dosage and high reactive oxygen species (ROS) selectivity remains a critical bottleneck hindering practical engineering applications. This study utilized nanodiamond with natural curvature as carriers to construct C-Fe_SAC catalysts. The geometric strain caused by surface curvature induces Fe 3d orbital splitting and spin rearrangement, triggering spin crossover and orbital state evolution, promoting an HS-to-MS spin-state evolution of the Fe centers. As versatile electron-transfer hubs, bifunctional FeN₄ active sites accelerate the formation of critical C-Fe_SAC-O*(PMS) intermediates and modulate the pathway of dissolved oxygen activation. This dual regulatory behavior achieves highly selective, multi-pathway generation of singlet oxygen (¹O₂). Based on the specific oxidation of low ionization potential guanine by ¹O₂, the catalyst achieved 4.7 log degradation of eARGs within 30 min and markedly suppressed the transformation activity of treated eARGs. The constructed Al₂O₃ catalytic membrane system still exhibits efficient eARGs removal performance under high-throughput conditions. This study clarifies the geometric strain-mediated ROS regulation mechanism, providing a facile and feasible strategy for practical eARG pollution control in water treatment.