Polyoxometalate-Derived Cu-MoO<sub>2</sub> Nanosheets as Electrocatalysts for Enhanced Acidic Water Oxidation
Parul Sood, Krishankant, Harshita Bagdwal, Arti Joshi, Krishna K. Yadav, Chandan Bera, Monika Singh
Abstract
In the era of renewable energy, electrocatalytic water splitting has always shown considerable potential. Consequently developing earth-abundant, affordable, and durable electrocatalysts for oxygen evolution is crucial. In this regard, polyoxometalates have been in the spotlight recently because of their attractive properties and well-defined molecular arrangement. Herein, we report a “polyoxometalate-derived” noble metal-free electrocatalyst for efficient oxygen evolution in “acidic” medium for the first time. An octamolybdate cluster-based solid, [(Cu(pic) 2 ) 2 (Mo 8 O 26 )]·8H 2 O (POM), served as the precursor to obtain the nanosheet-like electrocatalyst [Cu 0.1 -{MoO 2 } 0.9 ] (PS-55) which offered the overpotential of 374 mV to reach 10 mA cm –2 current density and a tafel slope of 193 mV dec –1, with the stability of 18 h. Density functional theory analysis revealed Mo as a prominent active site in PS-55. Projected density of states demonstrated a synergistic interaction between Cu-Mo d orbitals and O p orbitals, resulting in p-d mixing, a key factor driving the proficient oxygen evolution reaction. This work paves the way for studying POM-derived catalysts for acidic water oxidation.