Bismuth single-atom alloying of palladium nanosheets promotes selective electrochemical valorization of glycerol to C3 products

Abstract

The electrochemical oxidation of glycerol into value-added products (in particular C₃ products) offers an appealing approach for biomass valorization. Precious-metal-based catalysts are so far the only candidates that can deliver appreciable C₃ selectivity. Unfortunately, they generally have strong adsorption towards key reaction intermediates, leading to product over-oxidation and catalyst poisoning. To this end, we report that single atom alloying represents a promising solution, and demonstrate that bismuth atoms dispersed on palladium nanosheets significantly promote electrochemical glycerol oxidation to C₃ products. Under the optimal conditions, our catalyst exhibits an extraordinary C₃ faradaic efficiency of >90%, partial current density of >150 mA cm⁻² and operational stability over 30 h. All these metrics greatly surpass those of other precious-metal-based competitors reported earlier. Theoretical simulations unveil that the single atom alloying with Bi modulates the electronic structure of Pd and lowers the adsorption energies of reaction intermediates. Finally, we use glycerol oxidation as the anodic half reaction to pair with the CO₂ reduction reaction as the cathodic half reaction, and achieve the simultaneous valorization of glycerol and CO₂ with improved high energy efficiency and economic viability.