Boosting overall electrochemical water splitting via rare earth doped cupric oxide nanoparticles obtained by co-precipitation technique

The development of electrocatalyst based on nonprecious metals has been a persistent issue as electrochemical water splitting requires electrocatalyst with advanced activity and stability. Further, the electrocatalyst must require low overpotential above the standard potential (>1.23 V) of water splitting to produce hydrogen. This study presents the facile co-precipitation derived rare earth dysprosium (Dy) doped cupric oxide nanoparticles (Cu1−xDyxO) as a non-noble transition metal oxide nanoparticle. The 3 % Dy doped CuO (3 % Dy/CuO) and 1 % Dy doped CuO (1 % Dy/CuO) electrocatalysts showed excellent Oxygen Evolution Reaction (OER) at 1.55 V vs RHE and Hydrogen Evolution Reaction (HER) at − 0.036 V vs RHE in aqueous 1 M KOH aqueous electrolyte to attain the benchmark current density (10 mA cm−2). The stability of the driven electrocatalyst in a bi-functional electrocatalytic setup was monitored for 24 h and was found to be exhibiting a cell voltage of about 2.1 V at 30 mA cm−2 constant current density. Further, the retention capability of the electrode was observed to be 99 % with a very minimal loss. This study hugely suggests the promising consequence of doping rare earth onto a non-precious metal oxide-based electrocatalyst, making it a highly effective bifunctional material for water splitting. [Display omitted] •The OER for 3 % Dy-CuO was found to be 1.55 V vs RHE at 10 mA cm−2.•The HER for 1 % Dy-CuO was found to be − 0.036 V vs RHE at − 10 mA cm−2.•The two-electrode electrolyzer posted a cell voltage of 1.53 V at 10 mA cm−2.•The long-term stability of the setup was found to be 2.1 V@30 mA cm−2 for 24 h.