Arc plasma‐deposited Co single‐atom catalysts supported on an aligned carbon nanofiber for hydrogen peroxide electrosynthesis and an electro‐Fenton process
Chang‐Kyu Hwang, Sooyeon Kim, Sooyeon Kim, Ki Ro Yoon, Thao Thi Le, Van Chinh Hoang, Jae Won Choi, Wenjun Zhang, Sae Yane Paek, Chung Hyeon Lee, Ji Hyun Lee, Keun Hwa Chae, Sohee Jeong, Seung Yong Lee, Byeong‐Kwon Ju, Sang Hoon Kim, Sang Hoon Kim, Sang Soo Han, Jong Min Kim
Abstract
Abstract Atomically dispersed single‐atom catalysts (SACs) on carbon supports show great promise for H 2 O 2 electrosynthesis, but conventional wet chemistry methods using particulate carbon blacks in powder form have limited their potential as two‐electron (2e − ) oxygen reduction reaction (ORR) catalysts. Here, we demonstrate high‐performance Co SACs supported on a free‐standing aligned carbon nanofiber (CNF) using electrospinning and arc plasma deposition (APD). Based on the surface oxidation treatment of aligned CNF and precise control of the deposition amount in a dry‐based APD process, we successfully form densely populated Co SACs on aligned CNF. Through experimental analyses and density functional theory calculations, we reveal that Co SAC has a Co–N 2 –O 2 moiety with one epoxy group, leading to excellent 2e − ORR activity. Furthermore, the aligned CNF significantly improves mass transfer in flow cells compared to randomly oriented CNF, showing an overpotential reduction of 30 mV and a 1.3‐fold improvement (84.5%) in Faradaic efficiency, and finally achieves an outstanding production rate of 15.75 mol g cat −1 h −1 at 300 mA cm −2 . The high‐performance Co SAC supported on well‐aligned CNF is also applied in an electro‐Fenton process, demonstrating rapid removal of methylene blue and bisphenol F due to its exceptional 2e − ORR activity.