Electrochemical oxidation induced in-situ transformation of lamellar cobalt nitrate-hydroxide to oxygen vacancy-rich porous Ce Doped-CoOOH nanosheet for efficient oxygen evolution reaction

Abstract

Two-dimensional transition metal (2D TM)-based oxyhydroxides are widely used for electrocatalytic OER due to their high activity and low price. However, the limited active sites and insufficient intrinsic activity restrict their commercial applications. In this work, we develop a novel electrochemical oxidation etching-induced in-situ doping strategy to construct 2D oxygen vacancy (Ov)-rich porous Ce-doped CoOOH ultrathin nanosheets consisting of ultrafine nanocrystals on carbon cloth (Ce–CoOOH/CC) using lamellar cobalt nitrate-hydroxide on CC (CoLNH/CC) as the precursor for electrocatalytic OER. Benefiting from the abundant active sites and efficient mass/electron transfer rooted in the 2D ultrathin porous structure, as well as the optimized electronic structure resulting from Ce doping and Ov introducing, the Ce–CoOOH/CC exhibits a superior OER activity, with a low overpotential of 306 mV at 50 mA cm−2 and a small Tafel slope of 72.2 mV dec−1, compared to that of Co LHN/CC (368 mV and 93.9 mV dec−1), CeO2/Co LHN/CC (359 mV and 94.3 mV dec−1), and CoOOH/CC (337 mV and 75.9 mV dec−1) counterparts. Meanwhile, it shows good stability, with negligible current attenuation after 3000 cyclic voltammetry cycles or 24 h of continuous test. This study provides a feasible strategy for constructing various metal-doped porous transition metal oxyhydroxide-based electrocatalysts.