PdNi nanosheets with modulated d-band centers for efficient ethanol electrooxidation via the C2 pathway

Abstract

The ethanol electro-oxidation reaction (EOR) via the C₂ pathway holds great potential for the green production of high-value acetate and ethanol-boosted hydrogen production. However, the inappropriate adsorption of intermediates during the EOR on the catalyst surface impedes the realization of an optimized EOR performance. Herein, Pd_xNi_y alloy nanosheets are theoretically predicted and designed for efficient EOR via the C₂ pathway. The optimized composition can effectively adjust the surface electronic structure and Pd–Ni bond lengths of Pd_xNi_y, thereby precisely controlling the d-band center separation between Pd and Ni (Pd-ε_d/Ni-ε_d). This enables a more balanced adsorption of intermediates on the Pd_xNi_y surface and lowers the EOR energy barrier. Guided by this insight, we synthesized the theoretically predicted optimal composition, Pd₅Ni₁ nanosheets. Consequently, the Pd₅Ni₁ nanosheets exhibited a mass activity of 3554.66 mA mg_Pd⁻¹, significantly surpassing that of commercial Pd/C (115.59 mA mg_Pd⁻¹). In situ FTIR and DFT calculations illustrate that it follows the C₂ reaction mechanism during the EOR process.