Harnessing Iron Nitride Matrices through Incorporated Cu-Based Moieties for Chlorine Evolution Reaction

Chlorine evolution reaction (CER) is a critical reaction in many processes, such as chlor-alkali electrolysis and electrochemical wastewater treatment. The scarce and high-cost iridium and ruthenium content of benchmark dimensionally stable anodes (DSA) coupled with subpar activities at commercially relevant current densities (≥150 mA cm^-2) opens the door for additional material groups to be investigated. Herein, a highly porous, conductive, and chemically resilient trigonal ϵ-Fe₃N-based electroactive catalytic substrate is used toward CER in industrial acidic brine (4.0 M NaCl, pH = 2) environments. Consecutive hydrothermal-nitridation steps were fine-tuned for homogeneous dispersion of Cu₃N moieties atop FeN, which exhibited a similar overpotential to DSA at a commercially relevant current density. An approximately 562 mV overpotential was needed to sustain a current density of 200 mA cm^-2 for 75 h of chronoamperometric conditions. Moreover, online GC measurements with a chlorine trap were employed to indirectly obtain CER’s Faradaic efficiency (FE) by measuring the FE of the competing oxygen evolution reaction. Textural, chemical, and electrochemical characterization techniques were employed to confirm the identity of the developed anodes and depict the electrocatalytic performance. The findings reported herein could offer potential avenues for similar catalytic systems in both conventional CER and emerging electrosynthesis approaches utilizing saline waters.