Wet‐Spun PEDOT/CNT Composite Hollow Fibers as Flexible Electrodes for H 2 O 2 Production**

Abstract The electrochemical synthesis of hydrogen peroxide (H 2 O 2 ) using the oxygen reduction reaction (ORR) requires highly catalytic active, selective, and stable electrode materials to realize a green and efficient process. The present publication shows for the first time the application of a facile one‐step bottom‐up wet‐spinning approach for the continuous fabrication of stable and flexible tubular poly(3,4‐ethylene dioxythiophene) (PEDOT : PSS) and PEDOT : PSS/carbon nanotube (CNT) hollow fibers. Additionally, electrochemical experiments reveal the catalytic activity of acid‐treated PEDOT : PSS and its composites in the ORR forming hydrogen peroxide for the first time. Under optimized conditions, the composite electrodes with 40 wt % CNT loading could achieve a high production rate of 0.01 mg/min/cm 2 and a current efficiency of up to 54 %. In addition to the high production rate, the composite hollow fiber has proven its long‐term stability with 95 % current retention after 20 h of hydrogen peroxide production.