Electrochemical reduction of polycyclic aromatic compounds using microfibrous, high hydrogen overpotential electrodes.

摘要

The transformation of fundamental electrochemical technology into commercial processes that both meet societal needs and operate to generate a profit is the heart of industrial electrochemistry. However, few works have investigated inexpensive, efficient electrode design and electrolytic reactor engineering for direct electrochemical reduction of polycyclic aromatic compounds. The objective of this investigation was to design an effective process for electrochemically reducing these heavy hydrocarbons.; Porous microfibrous structures were manufactured utilizing Auburn University's technology for preparing nonwoven sheets of metal-cellulose preforms and sintering in a hydrogen environment. High hydrogen overpotential electrodes were fabricated by electroplating these substrates with micronic films of cadmium or zinc. Depositions were assessed using SEM and cyclic voltammetry to indicate complete, conformal coverage. AC impedance provided estimations of surface area and roughness for substrates and electrodes and confirmed non-rigorous model calculations.; Fabricated electrodes were utilized for stirred batch electroreduction of coal liquid, anthracene, and vanadium octa-ethylporphyrin. Feasibility of electrolytic hydrogenation for these reactants was demonstrated in both homogeneous phase and aqueous emulsion electrolytes despite gas evolution competition. Simultaneous electro-demetallization and electro-extraction of porphyrin bound vanadium in a hydrocarbon stream was shown for a liquid-liquid emulsion system. Finally, enhanced mass transfer performance was illustrated for fabricated microfibrous electrodes over planar geometries, and subsequent utilization in a laboratory flow-past reactor provided insight for industrial electrolytic design.