Nanoarchitectonics of Nickel Nitride-V2CTX Mxene: An Efficient Bifunctional Catalyst for Alkaline Water/Seawater Applications

Seawater, being the most plentiful natural water source worldwide, is a highly abundant and cost-efficient medium for producing hydrogen by alkaline water electrolysis. However, the advancement of seawater electrolysis is hindered by notable impediments caused by chloride corrosion at the anode and the simultaneous chlorine evolution process. Only a limited number of non-noble electrocatalysts demonstrate noteworthy bifunctional catalytic efficacy and long-term durability. In this regard, Nickel Nitride tailored V₂CT_X Mxene nanostructures is reported as a bifunctional catalyst for overall water/seawater applications. The optimized sample Ni₃N@3000-V₂CT_x exhibits low overpotential values of 90 and 300 mV in acidic and alkaline + seawater solutions respectively at 10 mA cm⁻² for hydrogen evolution reaction. Similarly, this catalyst shows 70 and 240 mV overpotential values in alkaline water and alkaline + seawater solutions respectively at the same current density for oxygen evolution reaction. Synergetic effects of Multiple Vanadium and Nickel valency along with compelling nitrogen bonds creates elevated density of exposed functional sites for electrocatalytic activity. Furthermore, the notable electrochemical active surface area and mass activity suggest an enhanced and significant presence of abundant active sites. Additionally, the high stability and significantly decreased charge transfer resistance expedited the overall water/seawater-splitting reaction rate.