Platinum substituted Cobalt(II, III) Oxide: Interplay of tetrahedral Co(II) sites towards electrochemical oxygen evolution activity

Nellaiappan, SubramanianSubramanianNellaiappanJhariya, NavneetNavneetJhariyaIrusta, SilviaSilviaIrustaSinghal, AditiAditiSinghal2025-08-312025-08-312021-01-0110.1016/j.electacta.2020.1372342-s2.0-85095436306http://repository.iitgn.ac.in/handle/IITG2025/23809Substitution of ionic platinum is carried out in Co<inf>3</inf>O<inf>4</inf> host synthesized by solution combustion strategy. These Pt substituted Co<inf>3</inf>O<inf>4</inf> spinels characterized by XRD show pure crystalline phase of Co<inf>3</inf>O<inf>4</inf> without any separated peaks related to Pt/PtO<inf>x</inf>. Electrochemical OER activities of these spinels are investigated by cyclic voltammetry, linear sweep voltammetry and chronoamperometry in neutral, alkaline and neutral buffer electrolytes. LSV studies on 1% Pt substituted Co<inf>3</inf>O<inf>4</inf> exhibit a low overpotential (η) of 455 mV at 20 mA cm−2 in KOH, as compared to PBS medium. Tafel slope value of 117 mV dec−1 in KOH represents one electron EC mechanism. The detailed XPS studies indicate that Pt doping increases the tetrahedral Co2+ sites of Co<inf>3</inf>O<inf>4</inf>. XPS studies before and after OER also infers that the mixed valence of Co in the host (Co<inf>3</inf>O<inf>4</inf>) undergoes redox (Co2+/Co3+) changes with simultaneous reduction in Pt dopant from Pt4+ to Pt2+ influencing the OER activity.falseElectrochemistry | Oxygen evolution | Pt-subsituted-Co3O4 | Solution combustion | Spinel oxidePlatinum substituted Cobalt(II, III) Oxide: Interplay of tetrahedral Co(II) sites towards electrochemical oxygen evolution activityArticlehttp://zaguan.unizar.es/record/1082771 January 202115137234arJournal18