Low-coordination PtBi heterogeneous interface boosting the selective electrooxidation of ethylene glycol to value-added glycolic acid

Abstract

The electrocatalytic oxidation of ethylene glycol (EG) into high-value chemicals like glycolic acid (GA) is a crucial step for upcycling waste plastics. However, catalyst deactivation and low selectivity pose significant challenges. This work presents the low-coordination PtBi nanosheets (LC-PtBi NSs), featuring a unique amorphous-crystalline heterostructure with a low coordination number of 2.3–2.5. They can exhibit exceptional mass activity (8.3 A mg_Pt⁻¹) and stability (maintaining 88.7 % of initial activity after running for 3600 s) of the EG oxidation reaction (EGOR). They also achieve over 90 % apparent selectivity for EG-to-GA conversion at low potentials (<0.7 V vs. RHE) and even more than 100-h continuous electrolysis. Density functional theory (DFT) calculations reveal that the low-coordination PtBi heterogeneous interface is responsible for the high coverage of OH_ad species and weakened adsorption of carbonaceous intermediates on LC-PtBi NSs, thereby promoting the direct oxidation of C₂ intermediates to GA. This work demonstrates a strategy of doping-mediated catalytic interface regulation and electron density rearrangement, offering insights for designing efficient Pt-based electrocatalysts toward selective oxidation of small molecules.