Performance analysis of three distinct Ni x V 2 O y single-phase nano self-assemblies for asymmetric supercapacitor fabrication and effective detection of low-concentration hazardous herbicide.

Single-phase inorganic nanostructures with multiple applications are required for cost-effective, sustainable applications to save the environment from toxic activities. Nickel vanadate (Ni x V 2 O y ), possessing three phases, such as NiV 2 O 6 , Ni 2 V 2 O 7 , and Ni 3 V 2 O 8 , acts as an effective electrode material and potential electrochemical sensors. Nickel vanadate phases (NiV 2 O 6 , Ni 2 V 2 O 7 , and Ni 3 V 2 O 8 ) were synthesized through the gel-matrix technique, and their phase purity, crystallinity, morphology, optical properties, etc ., were evaluated and studied. Electrochemical studies infer that NiV 2 O 6 exhibits the highest specific capacity of 251 C g -1 (69.7 mA h g -1 ) at 1 A g -1 compared to the other nickel vanadate phases and provides better cyclic stability of 80.19% for 5000 cycles. The asymmetric supercapacitor device fabricated from NiV 2 O 6 results in a specific capacity of 189 C g -1 (52.5 mA h g -1 ), energy density of 59.06 W h kg -1 , and a power density of 1125 W kg -1 with a capacitive retention rate of 74.91% and coulombic efficiency of 99.61% for 10 000 cycles. The electrochemical detection potential of Ni x V 2 O y in bifenox herbicide has been studied with all the synthesized nanostructures. Among them, NiV 2 O 6 -based sensor probes demonstrated excellent characteristics, including high sensing current and low detection limits of 0.6 nM with a linear range of 1-57 nM. The real-time herbicide detection of NiV 2 O 6 in live samples was checked with freshly harvested potatoes. This advancement further enhances the utilization of Ni x V 2 O y materials for electrochemical applications.