MOF-Derived Co3S4 Nanoparticles Embedded in Nitrogen-Doped Carbon for Electrochemical Oxygen Production.

The development of a simple and effective strategy for designing a highly efficient oxygen evolution electrocatalyst is more important to speed up the efficiency-limiting step involved in water electrolysis. The high efficiency of the oxygen evolution reaction (OER) is directly correlated with the class of electrode materials employed. This work reports a series of Co₃S₄ nanoparticles (Co₃S₄-2h, Co₃S₄-3h, and Co₃S₄-4h) derived from a metal–organic framework (MOF) via a single-step annealing strategy with varying reaction times for the study of OER. During the annealing process, the MOF precursor [Co₃(tiron-bpy)₂(bpy)-(H₂O)₈]·(H₂O)₂ termed as Co-T-BPY directly converted to cobalt sulfide (Co₃S₄) nanoparticles, along with additional support of the N-doped carbon moiety. Interestingly, variation of reaction time in a fixed temperature condition played a decisive role in optimizing the surface area with huge active sites of the derived products. The optimized Co₃S₄-3h product needed an overpotential of 285 mV to reach 10 mA cm^–2 current density and an acceptable Tafel value (109 mV dec^–1) with excellent 14 h of stability performance under harsh alkaline conditions. The OER results are attributed to the combined effect of the Co₃S₄ phase and N-doped carbon matrix, resulting in substantial stability and high conductivity. Therefore, we believe that the time variation strategy for the preparation of a cobalt-based non-precious electrode material can pave the way in search of an OER-efficient electrocatalyst. [ABSTRACT FROM AUTHOR]