Co/Co2N0.67/CeOx/coal-based porous carbon fibers as self-supporting electrode for synergistically enhanced overall water splitting

Coal-based carbon fibers (C-CFs) achieve the high value-added utilization of coal. • The Co/Co 2 N 0.67 /CeO x /C-PCFs catalyst is prepared by electrospinning and pyrolysis. • Pore creation in C-CFs enhances the synergy between cerium oxide and cobalt nitride. • The Co/Co 2 N 0.67 /CeO x /C-PCFs catalyst shows outstanding performance for OWS. Developing exceptional and economically viable electrocatalysts is crucial for advancing overall water splitting (OWS). Herein, a self-supporting electrode of Co/Co 2 N 0.67 /CeO x /coal-based porous carbon fibers (Co/Co 2 N 0.67 /CeO x /C-PCFs) is synthesized via electrospinning, hydrothermal reaction, and pyrolysis. The pore-creating strategy applied to coal-based carbon fibers (C-CFs) enhances the internal and external synergy between cerium oxide and cobalt nitride, and effectively modulates the electronic structure, promoting both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), thereby improving OWS performance. Moreover, by using acid- and alkali-tolerant C-PCFs as a support, the prepared electrode has a self-supporting structure, enabling it to undergo HER in both acidic and alkaline electrolyte solutions. The resulting Co/Co 2 N 0.67 /CeO x /C-PCFs electrode exhibits prominent electrocatalytic performance, with a low overpotential of 73 mV for HER in acidic media at 10 mA cm −2 , and in alkaline media, requiring only 93 mV for HER, 193 mV for OER, and a low cell voltage of 1.52 V for OWS at 10 mA cm −2 , with excellent stability over 240 h. In-situ Raman spectroscopy reveals that CeO x facilitates the reconstruction of cobalt species into CoOOH, thereby boosting OER activity. This study offers a reliable strategy for oxide/nitride composite catalysts and a new route converting coal to value-added carbon fibers. Download: Download high-res image (197KB) Download: Download full-size image