Fundamental Electrocatalytic Studies of High-Entropy Alloy Catalysts for Biomass-Derived Polyol Oxidation

High-entropy alloys (HEAs) have recently emerged as a versatile platform for electrocatalysis, offering diverse active sites, enhanced stability, and compositional flexibility. This project aims to establish fundamental structure–activity–selectivity relationships for HEA electrocatalysts applied to the electrooxidation of biomass-derived molecules, with primary focus on glycerol and ethylene glycol as model C2–C3 polyols. The research integrates controlled colloidal synthesis of multi-element nanoparticles with comprehensive structural and chemical characterization using X-ray diffraction (XRD), electron microscopy (SEM/TEM with EDS), X-ray photoelectron spectroscopy (XPS), and bulk composition analysis by ICP-OES. Advanced in situ and operando techniques, including X-ray absorption spectroscopy (XAS: XANES/EXAFS) and in situ XPS at the Brazilian Synchrotron Light Laboratory (LNLS), will be employed to probe electronic structure and coordination dynamics under electrochemical conditions. Complementary mechanistic insights will be obtained through in situ FTIR spectroscopy for detection of adsorbed intermediates during reaction. Electrochemical performance will be systematically evaluated using cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, and product analysis by HPLC/GC, enabling quantitative mapping of activity and selectivity across catalyst compositions. \hl{Higher polyols and furanic substrates (HMF, furfural) will be investigated as complementary systems, conditioned on the progress achieved in the main experimental stages.} Expected outcomes include the identification of composition-dependent active-site ensembles, mechanistic understanding of C–C bond cleavage versus selective dehydrogenation pathways, and the development of predictive design rules for HEA electrocatalysts.