Cobalt Iodate Precursor Induced Microstructural Tuning of Co 3 O 4 for High Current Density Alkaline OER Application at Industrial Conditions

Abstract 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 (IO 3 − ) moiety are used to synthesize crystalline Co 3 O 4 (named Co 3 O 4 ‐I) via calcination of Co(IO 3 ) 2 . The resulting crystalline Co 3 O 4 ‐I shows superior electrochemical OER performance using a carbon paper substrate compared to traditionally synthesized Co 3 O 4 (named Co 3 O 4 ‐U) and its amorphous cobalt hydroxy carbonate precursor (named Co(OH) 2 ). The Co 3 O 4 ‐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 Co 3 O 4 ‐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 Co 3 O 4 ‐I/NF demonstrates excellent durability for industrial conditions OER (72 h @ 500 mAcm −2 geo ). Experimental results suggest that the superior activity of Co 3 O 4 ‐I arises from increased surface area, crystal lattice defect generation, higher intrinsic activity, and active sites for Co 3 O 4 ‐I compared to Co 3 O 4 ‐U. The work offers an innovative methodology for the microstructural tuning of transition metal oxide materials by using their respective iodate precursor.