N-Coordinated Pd–Rh synergy for highly selective ethylene glycol oxidation and efficient hydrogen evolution

Abstract

The electrocatalytic oxidation of ethylene glycol as an anodic reaction (EGOR) offers a promising approach for producing both high-value chemicals and hydrogen. However, achieving high selectivity for desired products while maintaining catalytic efficiency remains a challenge. In this work, we present a novel bifunctional catalyst, N-PdRh@Ni(OH)₂ nanosheets (NSs), which excels in both the EGOR and the hydrogen evolution reaction (HER). The integration of N-coordinated PdRh bimetallic sites enables precise electronic modulation, optimizing the adsorption energies of key intermediates and enhancing selectivity for glycolic acid (GA). The negative charges on Pd improve the adsorption of EG and the desorption of the ^*OC–CH₂OH intermediate, while the positively charged Rh facilitates the adsorption of hydroxide ions (OH⁻) and the efficient generation of ^*OH radicals for the EGOR. The Pd–Rh synergy also promotes the hydrolytic dissociation of ^*H atoms into H₂, enhancing the HER activity. Remarkably, the catalyst-based membrane-free flow cell operates at just 0.85 V to achieve 100 mA cm⁻², requiring only 2.52 kW h m⁻³ for H₂ production while maintaining over 97.6% selectivity for GA upgrading. This work highlights an effective strategy for the electronic modulation of electrocatalysts and provides a promising approach for low-energy hydrogen production and sustainable biomass conversion.