A visible-light-driven polythiophene/MgAl-LDH@CuxS photocathode enhanced the generation of reactive oxygen species for water disinfection

Sea urchin-like Cu x S nanoflowers were prepared on copper foam substrate by in situ thermal oxidation and hydrothermal vulcanization. Then, thiophene (Th) was copolymerized with MgAl layered double hydroxide (MgAl-LDH) on Cu x S to obtain a polythiophene (PTh)/MgAl-LDH@Cu x S composite photocathode. Under visible-light irradiation, the electrode exhibits high photocurrent response and excellent stability for 72 h. Under an applied voltage of 3 V, the photogenic carrier was effectively separated, and combined with the graphite anode to generate highly oxidizing reactive oxygen species (ROS) and active chlorine directly and indirectly, which can achieve logarithmic inactivation of 7.57 and 7.07 log 10 CFU/mL against Escherichia coli and Bacillus subtilis within 15 and 25 min, respectively. The mechanism of photoelectrocatalytic reaction for disinfection was explored through cell membrane integrity, DNA/protein leakage and active substances analysis, and a free radical capture experiment proved that O 2 ∙– and h + played key roles in the disinfection process. The purification and degradation of different actual wastewaters show that the photoelectrocatalytic system has great practical application potential in water disinfection.