LAUSR

Gasification waste, also known as carbon soot, is solid industrial waste from the bottom residual of an oil refinery and contains a substantial amount of toxic vanadium. In this work, we report an environmentally responsible pathway to harvest toxic vanadium from gasification waste, and the extracted vanadium can be utilized to synthesize high-purity V2O5 nanosheets for the fabrication of flexible, bendable, efficient supercapacitors. The carbonaceous waste was first rinsed with alkaline solution to leach out toxic vanadium. The vanadium-rich leachate was next utilized to synthesize high-quality V2O5 crystals with comparable purity (>98%) and crystallinity to commercial products. Two-dimensional V2O5 nanosheets were further crystallized by hydrothermal treatment for the fabrication of high-performance electrochemical electrodes. The V2O5 electrodes derived from gasification waste demonstrated similar specific capacitance (172 F g–1) to those from commercial V2O5 (173 F g–1). The waste-derived V2O5 nanoshe...