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Sustainable Photovoltaic-Powered Series Electrochemical Reactors Using Nonactive Electrocatalytic Materials for Electro-Refinery in Organics and Energy Production

MetadataDetails
Publication Date2025-07-14
JournalACS Omega
AuthorsRainy Alves de Sousa, Lívia N. Cavalcanti, Amanda Duarte Gondim, Jussara Câmara Cardozo, Marco A. Quiróz
InstitutionsUniversidade Federal do Rio Grande do Norte, Universidade Estadual Paulista (Unesp)

The applicability of an electrochemical device with a series design and configuration, powered by photovoltaic panels, was tested as an integrated-hybrid approach for energy-efficient electrochemical green H<sub>2</sub> production coupled with dye effluent upgrading. This electrochemical strategy investigated the electroconversion efficiencies of a model organic compound into carboxylic acids by applying 15, 30, and 45 mA cm<sup>-2</sup>, with simultaneous production of green H<sub>2</sub>. Fluorine-doped lead oxide (PbO<sub>2</sub>-F) and boron-doped diamond (BDD) electrodes were used as anodes in a three-compartment flow reactor, in series mode with different anodic order: setting 1 (PbO<sub>2</sub>-F + BDD) and setting 2 (BDD + PbO<sub>2</sub>-F). PbO<sub>2</sub>-F was successfully prepared using the electrodeposition method, and it was characterized. The results clearly showed that configuration 1 (PbO<sub>2</sub>-F + BDD) consumed 10.47 kWh m<sup>-3</sup> after 120 min of electrolysis by applying 45 mA cm<sup>-2</sup>, achieving 42.5% organic removal efficiency and producing simultaneously 0.7 L of green H<sub>2</sub>. Meanwhile, the configuration 2 (BDD + PbO<sub>2</sub>-F) consumed 16.18 kWh m<sup>-3</sup> under the same operating conditions, achieving 47.5% organic load removal and producing 0.75 L of green H<sub>2</sub>. Discoloration of the effluent was efficiently achieved in all cases. Carboxylic acid production was monitored over time at different conditions tested. Notably, a selective production of malonic acid (28% conversion efficiency) was attained using setting 1, and consequently, upgrading the electro-refinery concept using wastewater residues.