Carbon-supported nickel-based bimetallic materials for electrochemical sensing and energy applications: A review

The rising demand for high-performance electrochemical sensors and energy storage devices has propelled research interest in advanced functional materials with enhanced catalytic activity, conductivity, and stability. Nickel-based materials have emerged as viable options due to their low cost and favourable redox properties; however, their practical application is often limited by low electrical conductivity and structural instability. The incorporation of carbon nanostructures, such as carbon nanotubes (CNTs), graphene derivatives, and graphene quantum dots (GQDs), with Ni-based bimetallic oxides offers a viable approach to address these constraints by facilitating enhanced electron transport, optimising the dispersion of active sites, and promoting synergistic catalytic effects. This review offers a critical assessment of recent developments in carbon-supported Ni-based bimetallic compounds for electrochemical sensing and energy storage applications. The role of carbon structures in enhancing charge transfer and stabilising bimetallic nanoparticles is examined, along with the roles of bimetallic systems arising from various redox-active centres. A comparative review of synthesis methodologies, electrochemical sensing capabilities, and energy storage features is presented to emphasise critical elements affecting material efficiency. Recent advancements in hybrid nanostructures have led to substantial enhancements in sensitivity, detection thresholds, capacitance, and cycling stability. Despite these advances, important challenges remain, including limitations in scalable synthesis, insufficient mechanistic understanding under realistic operating conditions, and performance degradation associated with structural instability and material ageing. Furthermore, trade-offs between conductivity, surface area, and long-term durability continue to constrain the optimisation of these systems. This review provides insights into the rational design of carbon-supported Ni-based bimetallic materials and outlines future research directions to bridge the gap between laboratory-scale performance and practical applications.