Cu-MOF-74-derived electrocatalysts for the electrochemical reduction of 2-nitroaniline as a representative nitroaromatic pollutant

This study reports the synthesis of copper-based electrocatalysts derived from Cu-MOF-74 precursor obtained via a room-temperature synthesis, through controlled pyrolysis at different temperatures (400 °C, 600 °C, and 800 °C). Comprehensive physicochemical and electrochemical characterization revealed that pyrolysis at 600 °C provides the optimal balance between graphitization, metallic copper formation, surface area, and formation of active Cu 0 /Cu 2 O phases. Working electrodes modified with a conductive composite ink consisting of the Cu/Cu 2 O@CM74-600 electrocatalyst and polypyrrole (PPy) exhibited enhanced redox behavior and superior electrocatalytic performance in the electrochemical reduction of 2-nitroaniline (2-NA), as a representative nitroaromatic pollutant, to o -phenylenediamine (o-PDA) in aqueous media. Chronoamperometric studies using carbon felt electrodes achieved a conversion efficiency of 87.2% after 90 min, with favorable turnover numbers and apparent rate constants. Compared to conventional chemical, photocatalytic, and biocatalytic approaches, this electrocatalytic system operates under mild conditions without external reducing agents, is reusable and scalable, and therefore represents a promising platform for the degradation of hazardous nitroaromatic pollutants in water.