Synergistic PEDOT-NiCo(OH)2 heterostructure for enhanced visible-light photocatalytic degradation of tetracycline

Photocatalysis has emerged as a promising strategy for antibiotic remediation in wastewater treatment owing to its environmentally benign nature, high efficiency, and cost-effectiveness. Herein, a PEDOT- NiCo(OH) 2 hybrid photocatalyst is successfully synthesized and, systematically investigated for visible-light-driven tetracycline (TC) degradation. Structural engineering via optimized incorporation of bimetallic hydroxide (NiCo(OH) 2 ) into the PEDOT markedly enhances the specific surface area (∼188 m 2 g −1 ) and pore size of 5.29 nm, while significantly narrowing the optical band gap to ∼1.79 eV, enabling efficient visible light harvesting. Electrochemical analyses demonstrate a substantially reduced charge-transfer resistance and an enhanced photocurrent response for PEDOT-Ni(OH) 2 2:1 (P-NCH21), indicating accelerated interfacial charge transport and suppressed electron–hole recombination. Consequently, P-NCH21 achieves an exceptional TC removal efficiency of 97.6% within 35 min under visible-light irradiation, far outperforming P-NH and PEDOT-Ni(OH) 2 3:1 (P-NCH31), having degradation efficiencies of 67 and 92%, respectively. Electron paramagnetic resonance (EPR) measurements confirm that the generation of reactive oxygen species, such as superoxide (•O 2 ⁻) and (•OH) are the reactive species that drives the photocatalytic degradation process. Furthermore, the hybrid photocatalyst exhibits excellent stability, retaining ∼96.8% of its initial activity after five consecutive cycles. This study highlights the potential of P-NCH21 as an efficient and robust photocatalyst for antibiotic remediation, providing new insights into the design of conductive polymer–based hybrid materials for environmental applications.