A strain-modulated CoRu alloy supported on nitrogen-doped carbon nanospheres for defect-driven industrial chlorine evolution electrocatalysis

Abstract

The development of high-performance chlorine evolution reaction (CER) catalysts with low noble metal content, superior selectivity, and excellent stability is urgently needed to address the limitations of commercial Ru/Ir-based catalysts, such as high cost, severe OER competition, and nanoparticle instability. In this study, an innovative strategy is employed to fabricate a CoRu@CN catalyst by leveraging polydopamine-derived nitrogen-doped carbon nanospheres to immobilize cobalt–ruthenium (CoRu) alloy nanoparticles through robust metal–nitrogen coordination bonds, while optimizing the electronic structure via bimetallic synergy and nitrogen-induced modulation. The as-prepared CoRu@CN catalyst exhibits outstanding CER performance, with a remarkably low overpotential of 154 mV at 100 mA cm⁻², a favorable Tafel slope of 68.18 mV dec⁻¹, and a high chlorine selectivity of 97–99% in 5 M NaCl (pH = 2), along with a 3.8-fold enhancement in the electrochemically active surface area, attributed to the defect-rich active sites generated by doping. Mechanistic investigations reveal that CoRu@CN operates via the Volmer–Krishtalik (V–K) pathway, where the kinetics of the rate-determining Krishtalik step is significantly promoted at elevated potentials. Meanwhile, the nitrogen-doped carbon scaffold not only suppresses nanoparticle agglomeration and phase separation through metal–nitrogen coordination but also enhances mass transport and conductivity, contributing to the catalyst's exceptional durability with 99.3% activity retention after 100 hours of testing. This work not only solves the long-standing industrial problem of nanoparticle instability in CER catalysis but also provides a novel design strategy for developing corrosion-resistant, high-efficiency electrocatalysts, highlighting the potential of CoRu@CN for scalable and energy-efficient chlor-alkali electrolysis.