Electrocatalyst deposition in copper, bismuth, tin antimony nanoparticles structure for vanadium (III) / vanadium (II) redox couple on the surface of carbon based electrode

Vanadium redox flow batteries (VRAB); it is one of popular energy storage systems because it is used with renewable energy sources, has high charge-discharge effciency, low maintenance requirement and doesn't contain harmful waste to environment. In VRAB, the reaction step of V3+/V2+ redox couple is slow and requires electrocatalysis to accelerate. For the first time in this work, alloy electrocatalysts containing binary, ternary and quaternary metal ions were used to catalyze the reaction of V3+/V2+ redox couple. For these purpose, antimony oxide, copper sulphate, bismuth oxide and tin sulphate compounds were used as metal ion sources. Electrochemical performance of VOSO4 in H2SO4 solution containing a single metal ion in the range of 0.4 V to -1.0 V were examined with cyclic voltammetry technique. Next, the electrochemical behavior of V3+/V2+ redox couple was studied using H2SO4 solution containing VOSO4's binary (Bi3+-Cu2+, Bi3+-Sb3+, Bi3+- Sn2+, Cu2+- Sb3+, Cu2+- Sn2+ and Sb3+-Sn2+), ternary (Cu2+-Sb3+-Sn2+, Bi3+-Cu2+-Sb3+, Bi3+-Sb3+-Sn2+ and Bi3+-Cu2+-Sn2+), quaternary (Bi3+-Cu2+-Sb3+-Sn2+) metal ions. Alloy electrocatalysts containing single, binary, ternary and quaternary metal ions deposited on graphite electrode surface was characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Photoelectron Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EES). Keywords: Vanadium redox flow battery, electrocatalyst, alloy, energy stroage, metal