Cobalt Iodate Precursor Induced Microstructural Tuning of Co₃O₄ for High Current Density Alkaline OER Application at...

The development of efficient and electrochemically stable catalysts for industrial-scale alkaline oxygen evolution reaction (OER) is the need of the hour. Herein, for the first time, the microstructural tuning abilities of iodate (IO₃ ^-) moiety are used to synthesize crystalline Co₃O₄ (named Co₃O₄-I) via calcination of Co(IO₃)₂. The resulting crystalline Co₃O₄-I shows superior electrochemical OER performance using a carbon paper substrate compared to traditionally synthesized Co₃O₄ (named Co₃O₄-U) and its amorphous cobalt hydroxy carbonate precursor (named Co(OH)₂). The Co₃O₄-I also shows an excellent lab-scale ambient OER performance (249 ± 4 mV@ 10 mAcm^-2 _geo) using a nickel foam (NF) substrate. Furthermore, the Co₃O₄-I demonstrates splendid OER performance (1.383 ± 0.003, 1.425 ± 0.002, and 1.501 ± 0.004 V @ 10, 100, and 500 mAcm^-2 _geo, respectively) at industrial conditions (6 M KOH, 85 °C). Additionally, the Co₃O₄-I/NF demonstrates excellent durability for industrial conditions OER (72 h @ 500 mAcm^-2 _geo). Experimental results suggest that the superior activity of Co₃O₄-I arises from increased surface area, crystal lattice defect generation, higher intrinsic activity, and active sites for Co₃O₄-I compared to Co₃O₄-U. The work offers an innovative methodology for the microstructural tuning of transition metal oxide materials by using their respective iodate precursor.