Valence state engineering of copper oxide nanorods: A unified catalyst platform for efficient cathodic nitrate reduction and anodic glycerol oxidation

The rational design of highly efficient bifunctional electrocatalysts, capable of robust operation across both oxidative and reductive electrochemical environments, is paramount for next-generation energy conversion and environmental remediation technologies. Crucially, a unified copper-based catalyst platform, engineered with precisely tailored oxidation states uniquely suited for disparate reaction conditions, offers a paradigm for substantially simplifying electrolyzer architectures without compromising electrocatalytic efficacy at either electrode. Herein, we address this challenge by synthesizing copper oxide nanorods (CuO NRs) possessing systematically modulated reduction extents. Electrochemical investigations demonstrate that partially reduced CuO NRs (r-CuO NRs) exhibit exceptional activity and selectivity for cathodic nitrate reduction to ammonia ( ${\mathrm{F}\mathrm{E}}_{{\mathrm{N}\mathrm{H}}_3\mathrm{\%}}=96.8\mathrm{\%}$), whereas pristine CuO NRs display superior performance for anodic glycerol oxidation to formate (FE_Formate% = 93%). These findings underscore the strategic imperative of precisely controlling copper oxidation state manipulation in advancing sustainable chemical synthesis and environmental remediation strategies.