Long‐Lasting Electrospun Co₃O₄ Nanofibers for Electrocatalytic Oxygen Evolution Reaction

Abstract

Electrocatalytic water splitting is one of the key phenomena in establishing renewable and sustainable energy technologies. Despite advances in hydrogen evolving industrial science, the oxygen electrochemistry lags behind due to the complexity in seeking suitable and stable electrocatalysts, in unifying electrolytic conditions and hence sluggish reaction kinetics. Herein, we report on the electrocatalytic activity of the cobalt oxide nanofibers in alkaline oxygen evolution reaction with a substantial operation lifetime of 120 hours. The unique preparation of fibers by electrospinning enables increased electrode networking and nanofibrous interaction thus leading to extended catalytically active surface area, imperative for wellperforming electrolysis. Operating at low overpotential of 293 mV at a current density of 10 mA cm À 2 , as well as low Tafel slope of 60.5 mV dec À 1 in 1 M KOH indicate the efficient utilization of nanofibrous Co 3 O 4 electrocatalyst towards oxygen evolution with an excellent long-term durability over 100 hours.

Novel mixed heterovalent (Mo/Co)Ox-zerovalent Cu system as bi-functional electrocatalyst for overall water splitting

“…CoO x –Cu@NF electrode gives anodic peaks at − 0.39 V corresponding to (Cu 0 to Cu 1+ ), broad peak at − 0.08 V corresponding to both (Cu 1+ to Cu 2+ ) and (Co 2+ to Co 3+ ), and broad peak at 0.34 V corresponding to (Co 3+ to Co 4+ ). The corresponding cathodic peaks are at 0.10 V (Co 4+ to Co 3+ ), − 0.34 (Co 3+ to Co 2+ ), shallow peak at − 0.55 V (Cu 2+ to Cu 1+ ) and − 0.8 V (Cu 1+ to Cu 0 ) 71 , 72 . Moreover, (Mo/Co)O x –Cu@NF electrode gives anodic peaks at − 0.7 V corresponding to (Mo 4+ to Mo 5+ ), − 0.38 V attributed to (Mo 5+ to Mo 6+ ) 73 , and (Cu 0 to Cu 1+ ), and − 0.04 V attributed to (Cu 1+ to Cu 2+ ), and (Co 2+ to Co 3+ ).…”

Hierarchical Co(OH)2 Dendrite Enriched with Oxygen Vacancies for Promoted Electrocatalytic Oxygen Evolution Reaction

“…However, the binding energy of Co 2p was ~0.6 eV higher in O V −Co(OH) 2 than in p-Co(OH) 2 . Specifically, the splitting peaks of 781.4 and 780.6 eV were derived from Co 2p 3/2 and attributed to Co 3+ and Co 2+ , and the peaks of 797.5 and 796.0 eV were derived from Co 2p 1/2 [20,23,24]. In order to clarify the state of Co, we also analysed the XPS spectra of C 1s (Figure S6).…”

Application of Electrospun Nanofibers for Fabrication of Versatile and Highly Efficient Electrochemical Devices: A Review

“…Similarly, diverse other materials were electrospun by using different polymers as spinning agents and different metals to form the final nanofiber mat after calcination, and applied for electrocatalytic water splitting, i.e., hydrogen or oxygen evolution reaction. Some of these metals or metal oxides are Co 3 O 4 [ 75 ], Co/Mo 2 C [ 76 ], and Ni 3 V 2 O 8 nanocube decorated nanofibers [ 77 ].…”