Tuning the Electrocatalytic Properties of VO 2 (B): Role of W Doping in Bifunctional Water Splitting

Abstract Vanadium‐based systems have evoked considerable interest in researchers due to their potential for advanced renewable energy technologies. However, the possibilities of VO 2 (B) as an electrocatalyst for water splitting are yet to be explored, even though it is an excellent candidate as an electrode material for various batteries. In this work, the bifunctionality of VO 2 (B) is investigated in overall water electrolysis, focusing on its enhanced catalytic activity when doped with transition metal atoms such as tungsten (W). Hydrothermally synthesized W‐doped VO 2 (B) nanoflakes demonstrate superior hydrogen evolution (HER) and oxygen evolution reactions (OER), confirming this enhanced catalytic activity. For an optimal W doping, the overpotential values decreased from 518 to 335 mV and 435 to 348 mV for hydrogen evolution and oxygen evolution, respectively. These observations are supported by the lowest Tafel slope values of 115 and 74 mV dec −1 for HER and OER, respectively, and the lowest charge transfer resistance of 47 Ω. The excellent stability of the nanostructures revealed by the chronopotentiometry demonstrates their reliable performance over extended periods. Together, these findings highlight that W‐doped VO 2 (B) nanostructures are highly effective candidates as electrocatalysts for overall water‐splitting applications.