The impact of graphene on the electrochemical performance of BiMeVOx catalysts in water splitting.

The development of efficient catalysts for electrochemical water splitting has become a significant contemporary challenge. Transition metal oxides, due to their unique electrochemical properties, have emerged as promising candidates. Among these, a group of BiMeVO x -based compounds shows particular potential for practical applications in hydrogen and oxygen evolution reactions. However, improvement is still necessary to achieve stable operation of these catalysts in green hydrogen generation. With this is mind, in this study we synthesize BiMeVO x materials with graphene addition using a simple annealing in a tube furnace and investigate their electrochemical properties in HER and OER. After incorporating different metals into the BiMeVO x structure, we observed variations in electrochemical properties; materials with the addition of molybdenum and cobalt (BiMoVO x and BiCoVO x) outperformed materials containing zirconium and cerium (BiZrVO x and BiCeVO x). The BiMoVOx/C catalyst showed excellent HER performance with an overpotential of 432 mV at 10 mA/cm2 and a Tafel slope of 76 mV dec⁻1, while BiCoVOx/C exhibited superior OER activity with a Tafel slope of 100 mV dec⁻1, lower than that of commercial IrO₂. The addition of graphene improved the conductivity and overall activity of the catalysts. These findings indicate that metal doping and graphene incorporation are effective strategies for enhancing the performance of BiMeVOx-based materials in water splitting applications. [Display omitted] • The addition of molybdenum and cobalt to the BiMeVO x structure improve the electrochemical properties. • Graphene was found to contribute to increased sample conductivity and catalyst activity. • The addition of molybdenum and graphene in BiMoVOx/C increased activity in HER with an overpotential at 432 mV. • The addition of cobalt and graphene in BiCoVOx/C improved catalytic performance with the Tafel slope a 100 mV dec−1. [ABSTRACT FROM AUTHOR]