Enhanced oxygen evolution performance by single metal (tungsten, nickel and manganese) atom oxides anchored nanorods of CeO2-MnO2-rGO as electrocatalysts

Background

In CeO₂₋MnO₂-based electrocatalysts for oxygen evolution, addressing issues of stability and electron transfer delay is crucial for practical applications. The modification of electronic structures through single metal oxides (W, Ni, and Mn) can potentially enhance electron mobility and improve metal-support interactions, thus boosting electrocatalytic activity.

Method

To this end, CeO₂₋MnO₂ nanorods intercalated with single metal atom oxides (SMAO) and supported by a reduced graphene oxide (rGO) layer (designated WNiMnCeMn-R-3) were synthesized using a sonication process.

Significant findings

This catalyst composition, particularly the WNiMnCeMn-R-3 variant with a CeO₂ to MnO₂ ratio of 15:45 %, exhibited significantly lower overpotential (280 mV) and Tafel slope (65.18 mV dec⁻¹) at a current density of 10 mA cm⁻² compared to other nanocomposites like CeO₂₋MnO₂, CeO₂₋MnO₂-rGO, WNiMnCeMn-R-1 (CeO₂:MnO₂ as 45:15 %) and WNiMnCeMn-R-2 (CeO₂:MnO₂ as 30:30 %). Exceptional electrochemical stability was demonstrated during a 24 h chronopotentiometry test over 2000 cyclic voltammetry cycles. The outstanding catalytic performance and stability of WNiMnCeMn-R-3 can be attributed to the synergistic effects of SMAO, CeO₂, MnO₂, and rGO layers, which collectively enhance the intrinsic catalytic activity and facilitate faster electron transport. This study aims to advance the development of electrochemical catalysts utilizing metal oxides, specifically SMAOs anchored onto rGO.