Unravelling the mechanism involved behind superior alkaline water electrolysis achieved from CeVO4/BiVO4 electrocatalytic system

Electrocatalytic water splitting system provides advantages to extract maximum from both OER and HER electrocatalysts. Here, we report a novel electrocatalytic system comprising of p-type CeVO 4 and n-type BiVO 4 as oxygen and hydrogen evolution catalysts, respectively. The optimized 0.5 mol (urea + NH 4 F) composition for both CeVO 4 and BiVO 4 demonstrates enhanced crystallinity, optimal particle size distribution, and superior structural integrity. Operating in alkaline medium of 1 M KOH, this binary system achieves remarkable water splitting performance with a notably low cell potential of ∼1.52 V at 10 mA cm −2 , outperforming the benchmark conventional system. The catalyst system maintains exceptional stability, exhibiting only ∼15% current density decay over 200 h of continuous operation and a minimal overpotential increase of ∼20 mV after 200 h. This outstanding performance is attributed to the synergistic effects between the metal centers, optimized electronic structures, and carefully controlled morphology of both catalysts.