Au Single‐Atom Anchored TiO ₂ Nanotube Array Membrane for Photoelectrocatalytic Accurate Removal of Mercaptan Contaminants Under Continuous‐Flow Conditions

Abstract Low concentrations of highly toxic mercaptans (MCs) are resistant to biodegradation and advanced oxidation processes (AOPs) in the presence of high concentrations of dissolved organic matter (DOM). Here, a photoelectrocatalytic continuous‐flow nanoreactor (PEC‐CFN) is designed by loading Au single‐atoms (Au SAs) into the tubes of TiO 2 nanotube array membrane (TiO 2 NAM), enabling highly efficient and selective MCs removal. Under continuous‐flow conditions, PEC‐CFN creates a microenvironment within the tubes characterized by high ·OH concentrations (≈75 µM). Moreover, the presence of Au SAs promotes charge separation, further enhancing PEC performance. Consequently, PEC‐CFN significantly reduces 50 µg L −1 MCs to below 0.7 µg L −1 under high‐flux conditions and retains 67.5% of its initial pseudo‐first‐order degradation kinetic constant even coexists with 1000‐fold DOM. The high selectivity of PEC‐CFN results from the formation of stable Au─S bonds, which enhances the preferential adsorption of MCs over DOM under high‐flux conditions. Additionally, the PEC‐CFN system achieves deep mineralization and simultaneous removal of total organic carbon (TOC) during MCs degradation. This study highlights the effectiveness of PEC‐CFN in the selective removal of trace MCs from complex systems.