Pd-Ru anchored on CaO derived from waste-eggshells for ethanol oxidation electrocatalysis.

• An advanced eggshells-CaO supported Pd-Ru nanocatalysts is successfully constructed. • Pd and Ru NPs are uniformly-dispersed on CaO with small size leading to high ECSA. • Physical characterizations show that Ru enhanced the electronic structure of Pd NPs. • The Pd-Ru/CaO exhibits superior electrocatalytic activity and long term stability towards EOR process. • The excellent performance is attributed to the well-organized structure and bimetallic synergy effect. Herein, we developed a unique Pd-Ru nanocatalyst supported on CaO derived from waste eggshells via a direct sodium borohydride chemical reduction strategy for the electrooxidation of ethanol under mild conditions. The electronic state and size of the alloy nanoparticles can be effectively optimized by taking advantage of the strong electron interactions between Pd and Ru, alleviating the CO poisoning and aggregation issues of the catalytic species. The morphological characterization results demonstrate that the Pd-Ru/CaO has a well-defined morphology with uniform metal dispersion and a high surface area. XRD and XPS patterns revealed that Ru causes a shift in the electronic band of Pd, which leads to a desired structure with a high ECSA. Furthermore, the Pd-Ru/CaO electrocatalyst has significantly higher electrocatalytic activity (3581.1 mA mg Pd + Ru − 1), long-term stability, and improved CO ads antitoxic tolerance than the supportless Pd-Ru (2779.57 mA mg Pd + Ru − 1), Pd/CaO (1603.6 mA mg Pd + Ru − 1), and Pd/C (JM) (587.4 mA mg Pd + Ru − 1) nanocatalysts. The outstanding electrocatalytic performance was due to the usage of high surface area CaO NPs as the supports and the synergetic effect of Pd and Ru NPs in EOR process. The proposed rational designed Pd-Ru/CaO nanocatalysts with well-defined morphology and small particle sizes could contribute to enhancing the performance of Pd-based nanoocatalysts and favor the overall DEFC process. [Display omitted] [ABSTRACT FROM AUTHOR]