Cobalt Vanadium Bimetallic Oxide Nanoplates Modified with RuO2 for Efficient Electrocatalytic Overall Water Splitting

Abstract

The construction of bifunctional electrocatalysts with high activity and stability presents a considerable challenge that has significant implications for energy conversion technologies. Herein, we successfully synthesized a porous cobalt vanadium bimetallic oxide nanoplate modified by RuO2 as a bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The introduction of a small amount of Ru leads to significant surface reconstruction of cobalt vanadium bimetallic oxides, with a nearly two-fold increase in specific surface area and a 4.5-fold increase in electrochemical surface area compared to the ruthenium free sample. Additionally, density functional theory (DFT) analysis indicates that the modification of RuO2 leads to the redistribution of electrons at the interface, adjusts the d-band center, thereby optimizing the adsorption and desorption of intermediates, reducing the reaction energy barrier, and accelerating the kinetics of the catalytic reaction. Consequently, the optimized Ru-CoVO-4 catalyst demonstrates excellent catalytic activity with low overpotentials of 49 mV for the HER and 220 mV for the OER at 10 mA cm-2 in a 1 M KOH solution, while also maintaining excellent stability. The electrolytic cell assembled with Ru-CoVO-4 requires only a cell voltage of 1.46 V to achieve 10 mA cm-2 and can operate stably for 500 hours. Notably, the Ru-CoVO-4 catalyst exhibits good HER activity under both acidic and neutral conditions, demonstrating its versatility across various applications.