PdNi nanosheets with coordinated d-d orbitals for efficient ethanol electrooxidation via the C2 pathway

Abstract

The ethanol electro-oxidation reaction (EOR) via the C2 route holds huge potential for the green production of high value-added acetate, as well as ethanol-boosted hydrogen production. However, inappropriate adsorption of intermediates in the EOR reaction on catalyst surfaces impends the realization of optimized EOR performance. Herein, PdxNiy alloy nanosheets composed of different Pd and Ni atoms 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 length of PdxNiy, thereby well-controlling the d-band center separation between Pd and Ni (Pd-ɛd/Ni-ɛd). This enables a more balanced adsorption of intermediates on the PdxNiy surface and lowers the EOR reaction energy barrier. Guided by this insight, we constructed the theoretically predicted optimal composition catalyst, Pd5Ni1 nanosheets. Resultantly, the Pd5Ni1 nanosheet exhibited a mass activity of 3554.66 mA/mg, significantly surpassing that of commercial Pd/C (115.59 mA/mg). In-situ FTIR and DFT calculations illustrate that it follows the C2 reaction mechanism during the EOR process.