Strong p–d Orbital Hybridization in Atomically Ordered Intermetallic Pd3Bi Metallene Enables Energy-Efficient Simultaneous Electrosynthesis of a Nylon-6 Precursor and Glycolic Acid

Abstract

Aqueous electro-reductive coupling of nitrogen oxides and cyclohexanone to produce cyclohexanone oxime (CYCO) has recently attracted much interest, but it is greatly challenging due to its low yield and poor energy efficiency. Herein, an intermetallic Pd₃Bi metallene (i-Pd₃Biene) catalyst was developed to drive the electrosynthesis of CYCO from nitrite and cyclohexanone at an almost 100% yield and Faradaic efficiency (FE) of 46.09%. Moreover, the i-Pd₃Biene also performed well for the electro-reforming of polyethylene terephthalate to synthesize glycolic acid (GA, FE: 96.63%). Detailed mechanism studies demonstrated that the interatomic strong p–d orbital hybridization evokes electron transfer from Bi to Pd and leads to electron localization on ordered Pd atoms, which shows positive effects on optimizing the adsorption equilibrium of key intermediates and directionally switching the reaction pathways to synthesize desired products. With such fundamental understanding, the bifunctional i-Pd₃Biene is further employed to assemble an asymmetric coupled electrocatalysis system, achieving simultaneous energy savings in electrosynthesis of CYCO and GA.