Layer‐by‐Layer Coating of Cobalt‐Based Ink for Large‐Scale Fabrication of OER Electrocatalyst

The scalability and stability of electrocatalysts is one of the biggest challenges for their practical applicability. In this context, Co 3 O 4 nanoparticles conformally coated on a light weight, 3D and highly conducting carbon cloth are fabricated using an easily synthesized cobalt hexadecylthiolate complex as ink. This method is especially useful for large‐scale production as the complex is synthesized in large quantities and coated on 3D substrates by a simple dip‐coating method. The optimum loading of the catalyst is achieved through a layer‐by‐layer (LbL) assembly of a cobalt hexadecylthiolate complex via repeated dip coating of the carbon cloth electrode in the solution. The Co 3 O 4 /CC undergoes electrochemical oxidation and converts to CoOOH as an active species and acts as a highly efficient electrocatalyst with optimized loading. The Co 3 O 4 ‐16/CC with 16 times dip coating exhibits remarkable stability over 24 h with an overpotential of 300 mV at 10 mA cm −2 and a Tafel slope of 77.06 mV dec −1 . The electrocatalytic activity of Co 3 O 4 ‐16/CC prepared by LbL coating is better than conventional Co 3 O 4 and comparable to IrO 2 and RuO 2 electrocatalysts with the future possibility of commercial‐scale production at lower cost.